1. |
- Connolly-Andersson, Anne-Marie, et al.
(författare)
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Puumala virus infections associated with cardiovascular causes of death
- 2013
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 19:1, s. 126-128
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Tidskriftsartikel (refereegranskat)abstract
- We studied the causes of death of patients in Sweden with diagnoses of hemorrhagic fever with renal syndrome (HFRS) during 1997–2009. Cardiovascular disorders were a common cause of death during acute-phase HFRS and were the cause of death for >50% of those who died during the first year after HFRS.
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2. |
- Gnann, J. W., et al.
(författare)
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Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy
- 2015
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 61:5, s. 683-691
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Tidskriftsartikel (refereegranskat)abstract
- Background. Despite the proven efficacy of acyclovir (ACV) therapy, herpes simplex encephalitis (HSE) continues to cause substantial morbidity and mortality. Among patients with HSE treated with ACV, the mortality rate is approximately 14%-19%. Among survivors, 45%-60% have neuropsychological sequelae at 1 year. Thus, improving therapeutic approaches to HSE remains a high priority. Methods. Following completion of a standard course of intravenous ACV, 87 adult patients with HSE (confirmed by positive polymerase chain reaction [PCR] for herpes simplex virus DNA in cerebrospinal fluid) were randomized to receive either valacyclovir (VACV) 2 g thrice daily (n = 40) or placebo tablets (n = 47) for 90 days (12 tablets of study medication daily). The primary endpoint was survival with no or mild neuropsychological impairment at 12 months, as measured by the Mattis Dementia Rating Scale (MDRS). Logistic regression was utilized to assess factors related to the primary endpoint. Results. The demographic characteristics of the 2 randomization groups were statistically similar with no significant differences in age, sex, or race. At 12 months, there was no significant difference in the MDRS scoring for VACV-treated vs placebo recipients, with 85.7% and 90.2%, respectively, of patients demonstrating no or mild neuropsychological impairment (P = .72). No significant study-related adverse events were encountered in either treatment group. Conclusions. Following standard treatment with intravenous ACV for PCR-confirmed HSE, an additional 3-month course of oral VACV therapy did not provide added benefit as measured by neuropsychological testing 12 months later in a population of relatively high-functioning survivors.
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3. |
- Lwande, Olivia Wesula, et al.
(författare)
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Experimental Infection and Transmission Competence of Sindbis Virus in Culex torrentium and Culex pipiens Mosquitoes from Northern Sweden
- 2019
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert. - 1530-3667 .- 1557-7759. ; 19:2, s. 128-133
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Sindbis virus (SINV) is a mosquito-borne Alphavirus known to infect birds and cause intermittent outbreaks among humans in Fenno-Scandia. In Sweden, the endemic area has mainly been in central Sweden. Recently, SINV infections have emerged to northern Sweden, but the vectorial efficiency for SINV of mosquito species in this northern region has not yet been ascertained.Objective: Mosquito larvae were sampled from the Umea region in northern Sweden and propagated in a laboratory to adult stage to investigate the infection, dissemination, and transmission efficiency of SINV in mosquitoes.Materials and Methods: The mosquito species were identified by DNA barcoding of the cytochrome oxidase I gene. Culex torrentium was the most abundant (82.2%) followed by Culex pipiens (14.4%), Aedes annulipes (1.1%), Anopheles claviger (1.1%), Culiseta bergrothi (1.1%), or other unidentified species (1.1%). Mosquitoes were fed with SINV-infected blood and monitored for 29 days to determine the viral extrinsic incubation period. Infection and dissemination were determined by RT-qPCR screening of dissected body parts of individual mosquitoes. Viral transmission was determined from saliva collected from individual mosquitoes at 7, 14, and 29 days. SINV was detected by cell culture using BHK-21 cells, RT-qPCR, and sequencing.Results: Cx. torrentium was the only mosquito species in our study that was able to transmit SINV. The overall transmission efficiency of SINV in Cx. torrentium was 6.8%. The rates of SINV infection, dissemination, and transmission in Cx. torrentium were 11%, 75%, and 83%, respectively.Conclusions: Cx. torrentium may be the key vector involved in SINV transmission in northern Sweden.
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4. |
- Lwande, Olivia Wesula, et al.
(författare)
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Mosquito-borne Inkoo virus in northern Sweden - isolation and whole genome sequencing
- 2017
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Ingår i: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Inkoo virus (INKV) is a less known mosquito-borne virus belonging to Bunyaviridae, genus Orthobunyavirus, California serogroup. Studies indicate that INKV infection is mainly asymptomatic, but can cause mild encephalitis in humans. In northern Europe, the sero-prevalence against INKV is high, 41% in Sweden and 51% in Finland. Previously, INKV RNA has been detected in adult Aedes (Ae.) communis, Ae. hexodontus and Ae. punctor mosquitoes and Ae. communis larvae, but there are still gaps of knowledge regarding mosquito vectors and genetic diversity. Therefore, we aimed to determine the occurrence of INKV in its mosquito vector and characterize the isolates.Methods: About 125,000 mosquitoes were collected during a mosquito-borne virus surveillance in northern Sweden during the summer period of 2015. Of these, 10,000 mosquitoes were processed for virus isolation and detection using cell culture and RT-PCR. Virus isolates were further characterized by whole genome sequencing. Genetic typing of mosquito species was conducted by cytochrome oxidase subunit I (COI) gene amplification and sequencing (genetic barcoding).Results: Several Ae. communis mosquitoes were found positive for INKV RNA and two isolates were obtained. The first complete sequences of the small (S), medium (M), and large (L) segments of INKV in Sweden were obtained. Phylogenetic analysis showed that the INKV genome was most closely related to other INKV isolates from Sweden and Finland. Of the three INKV genome segments, the INKV M segment had the highest frequency of non-synonymous mutations. The overall G/C-content of INKV genes was low for the N/NSs genes (43.8–45.5%), polyprotein (Gn/Gc/NSm) gene (35.6%) and the RNA polymerase gene (33.8%) This may be due to the fact that INKV in most instances utilized A or T in the third codon position.Conclusions: INKV is frequently circulating in northern Sweden and Ae. communis is the key vector. The high mutation rate of the INKV M segment may have consequences on virulence
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5. |
- Wilhelmsson, Peter, et al.
(författare)
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A prospective study on the incidence of Borrelia burgdorferi sensu lato infection after a tick bite in Sweden and On the Åland Islands, Finland (2008-2009)
- 2016
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Ingår i: Ticks and Tick-borne Diseases. - : Elsevier. - 1877-959X .- 1877-9603. ; 7:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- Lyme borreliosis (LB) is a common and increasing tick-borne disease in Europe. The risk of acquiring a Borrelia infection after a tick bite is not fully known. Therefore, we investigated the incidence of Borrelia infection after a bite by a Borrelia-infected tick and if the Borrelia load and/or the duration of tick-feeding influenced the risk of infection. During 2008-2009, ticks and blood samples were collected from 1546 tick-bitten persons from Sweden and the Åland Islands, Finland. Follow-up blood samples were taken 3 months after the tick bite. The duration of tick feeding was microscopically estimated and Borrelia was detected and quantified in ticks by real-time PCR. Anti-Borrelia antibodies were detected in sera using ELISA tests and immunoblot. Five percent (78/1546) of the study participants developed Borrelia infection (LB diagnosis and/or seroconversion) after a tick bite (45% bitten by Borrelia-infected ticks and 55% bitten by uninfected ticks). Of these, 33 developed LB (whereof 9 also seroconverted) while 45 participants seroconverted only. Experience of non-specific symptoms was more frequently reported by Borrelia-infected participants compared to uninfected participants. All who seroconverted removed "their" ticks significantly later than those who did not. The Borrelia load in the ticks did not explain the risk of seroconversion. Regional and sex differences in the Borrelia seroprevalence were found. The risk of developing a Borrelia infection after a bite by a Borrelia-infected tick is small but increases with the duration of tick feeding.
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6. |
- Abdelrahim, Nada A., et al.
(författare)
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Human herpes virus type-6 is associated with central nervous system infections in children in Sudan
- 2022
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Ingår i: African Journal of Laboratory Medicine. - : AOSIS. - 2225-2002 .- 2225-2010. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Human herpes virus type-6 (HHV-6) is increasingly recognised as a febrile agent in children. However, less is known in sub-Saharan African countries, including Sudan.Objective: We investigated the involvement of HHV-6 in paediatric central nervous system (CNS) infections in Khartoum, Sudan.Methods: Febrile patients aged up to 15 years with suspected CNS infections at Omdurman Hospital for Children from 01 December 2009 to 01 August 2010 were included. Viral DNA was extracted from leftover cerebrospinal fluid (CSF) specimens and quantitatively amplified by real-time polymerase chain reaction (PCR) at Umeå University in Sweden.Results: Of 503 CSF specimens, 13 (2.6%) were positive for HHV-6 (33.0% [13/40 of cases with proven infectious meningitis]). The median thermal cycle threshold for all HHV-6-positive specimens was 38 (range: 31.9-40.8). The median number of virus copies was 281.3/PCR run (1 × 105 copies/mL CSF; range: 30-44 × 103 copies/PCR run [12 × 103 - 18 × 106 copies/mL CSF]). All positive patients presented with fever and vomiting; 86.0% had seizures. The male-to-female ratio was 1:1; 50.0% were toddlers, 42.0% infants and 8.0% teenagers. Most (83.0%) were admitted in the dry season and 17.0% in the rainy season. Cerebrospinal fluid leukocytosis was seen in 33.0%, CSF glucose levels were normal in 86.0% and low in 14.0%, and CSF protein levels were low in 14.0% and high in 43.0%.Conclusion: Among children in Sudan with CNS infections, HHV-6 is common. Studies on the existence and spread of HHV-6 chromosomal integration in this population are needed.
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7. |
- Abdelrahim, Nada Abdelghani, et al.
(författare)
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Viral meningitis in Sudanese children : differentiation, etiology and review of literature
- 2022
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Ingår i: Medicine. - : Lippincott Williams & Wilkins. - 0025-7974 .- 1536-5964. ; 101:46
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Forskningsöversikt (refereegranskat)abstract
- Diagnosis of viral meningitis (VM) is uncommon practice in Sudan and there is no local viral etiological map. We therefore intended to differentiate VM using standardized clinical codes and determine the involvement of herpes simplex virus types-1 and 2 (HSV-1/2), varicella zoster virus, non-polio human enteroviruses (HEVs), and human parechoviruses in meningeal infections in children in Sudan. This is a cross-sectional hospital-based study. Viral meningitis was differentiated in 503 suspected febrile attendee of Omdurman Hospital for Children following the criteria listed in the Clinical Case Definition for Aseptic/Viral Meningitis. Patients were children age 0 to 15 years. Viral nucleic acids (DNA/RNA) were extracted from cerebrospinal fluid (CSF) specimens using QIAamp® UltraSens Virus Technology. Complementary DNA was prepared from viral RNA using GoScriptTM Reverse Transcription System. Viral nucleic acids were amplified and detected using quantitative TaqMan® Real-Time and conventional polymerase chain reactions (PCRs). Hospital diagnosis of VM was assigned to 0%, when clinical codes were applied; we considered 3.2% as having VM among the total study population and as 40% among those with proven infectious meningitis. Two (0.4%) out of total 503 CSF specimens were positive for HSV-1; Ct values were 37.05 and 39.10 and virus copies were 652/PCR run (261 × 103/mL CSF) and 123/PCR run (49.3 × 103/mL CSF), respectively. Other 2 (0.4%) CSF specimens were positive for non-polio HEVs; Ct values were 37.70 and 38.30, and the approximate virus copies were 5E2/PCR run (~2E5/mL CSF) and 2E2/PCR run (~8E4/mL CSF), respectively. No genetic materials were detected for HSV-2, varicella zoster virus, and human parechoviruses. The diagnosis of VM was never assigned by the hospital despite fulfilling the clinical case definition. Virus detection rate was 10% among cases with proven infectious meningitis. Detected viruses were HSV-1 and non-polio HEVs. Positive virus PCRs in CSFs with normal cellular counts were seen.
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8. |
- Affognon, Hippolyte, et al.
(författare)
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Ethnic groups' knowledge, attitude and practices and Rift Valley fever exposure in Isiolo County of Kenya
- 2017
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Ingår i: PLoS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2727 .- 1935-2735. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Rift Valley fever (RVF) is an emerging mosquito-borne viral hemorrhagic fever in Africa and the Arabian Peninsula, affecting humans and livestock. For spread of infectious diseases, including RVF, knowledge, attitude and practices play an important role, and the understanding of the influence of behavior is crucial to improve prevention and control efforts. The objective of the study was to assess RVF exposure, in a multiethnic region in Kenya known to experience RVF outbreaks, from the behavior perspective. We investigated how communities in Isiolo County, Kenya were affected, in relation to their knowledge, attitude and practices, by the RVF outbreak of 2006/2007. A cross-sectional study was conducted involving 698 households selected randomly from three different ethnic communities. Data were collected using a structured questionnaire regarding knowledge, attitudes and practices that could affect the spread of RVF. In addition, information was collected from the communities regarding the number of humans and livestock affected during the RVF outbreak. This study found that better knowledge about a specific disease does not always translate to better practices to avoid exposure to the disease. However, the high knowledge, attitude and practice score measured as a single index of the Maasai community may explain why they were less affected, compared to other investigated communities (Borana and Turkana), by RVF during the 2006/2007 outbreak. We conclude that RVF exposure in Isiolo County, Kenya during the outbreak was likely determined by the behavioral differences of different resident community groups. We then recommend that strategies to combat RVF should take into consideration behavioral differences among communities.
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9. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Brain abscess caused by methicillin-resistant Staphylococcus aureus
- 2000
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 32:5, s. 562-563
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Tidskriftsartikel (refereegranskat)abstract
- A Swedish tourist was admitted to a Cuban hospital due to epileptic seizures caused by brain tumors. Upon return to Sweden and admission to our hospital, methicillin-resistant Staphylococcus aureus (MRSA) was isolated. He was later considered to be free of MRSA but then developed a brain abscess from which MRSA was isolated.
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10. |
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11. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Central nervous system and ophthalmic involvement in nephropathia epidemica (European type of haemorrhagic fever with renal syndrome)
- 1998
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Ingår i: Journal of Infection. - 0163-4453 .- 1532-2742. ; 36:2, s. 149-155
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Tidskriftsartikel (refereegranskat)abstract
- Central nervous system (CNS) - related symptoms occur in haemorrhagic fever with renal syndrome (HFRS). To study the CNS and ophthalmic involvement in nephropathia epidemica (NE), the European type of HFRS, we included 26 patients in a prospective study. Most common CNS-related symptoms were headache (96%), insomnia (83%), vertigo (79%), nausea (79%), and vomiting (71%). Ophthalmic symptoms were reported by 82% of patients; 41% had photophobia and 50% had impaired vision. A transient loss of vision was recorded in one patient, who also had a generalized seizure. Minor white matter lesions were found in about half of the patients investigated with brain magnetic resonance imaging (MRI). Electroencephalography (EEG) showed severe alterations in only one patient, and slight and reversible patterns in another two patients. Neopterin, interleukin-6 and interferon-gamma levels in the cerebrospinal fluid (CSF) were elevated, which may indicate immune activation. However, we found no evidence of intrathecal NE virus replication. We conclude that CNS-related symptoms are common in NE, and transient ophthalmic involvement can be demonstrated in about half of the patients.
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12. |
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13. |
- Ahlm, Clas, 1956-
(författare)
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Distribution of puumala virus in Sweden
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Puumala virus, belonging to the genus hantavirus, is the causative agent of nephropathia epidemica (NE), a relatively mild form of hemorrhagic fever with renal syndrome. Puumala virus occurs endemically in Central and Northern Europe and Western Russia. In Sweden, NE is reported from the northern and central parts but virtually not at all from the southern part of the country. The bank vole (Clethrionomys glareolus) is the main reservoir of Puumala virus and humans are infected by inhalation of aerosolized animal secreta. In northern Sweden, the density of the bank vole population varies cyclically in intervals of 3-4 years and the incidence of NE shows a covariation.The prevalence of serum antibodies to hantaviruses in northern Sweden was studied in a stratified and randomly selected adult population sample comprising 1538 subjects. As expected, the prevalence increased with age. There was no difference between men and women, which was unexpected based on a male:female ratio of > 2:1 in clinical reports. By use of an immunofiuorescent assay, a seroprevalence of 5.4% and by a newly developed enzyme-linked immunosorbent assay (ELISA) with recombinant Puumala virus nucleocapsid protein as antigen, a prevalence of 8.9% was recorded. This is about or more than ten times higher than what would be calculated from clinical reports.By use of the ELISA, an occupational risk of acquisition of Puumala virus infection was demonstrated. Serum samples from 910 farmers and 663 referent subjects living in various rural parts of Sweden were tested. Among farmers from the Puumala virus-endemic northern and central parts of the country, the seroprevalence (12.9%) was higher (p=0.01) than in referents (6.8%). In the southern part of Sweden, only 2/459 persons had antibodies. Only a limited number of children with NE had been previously reported. In a separate study, 32 children with Puumala virus infection were identified and the clinical picture of NE in children was found to be similar to that of adult cases.Variations in the prevalence of Puumala virus in the bank vole population within an endemic region are not well known. Here, a higher mean rodent density and a higher prevalence of Puumala virus-specific serum antibodies were recorded in the vicinity of households afflicted with NE than in rural control areas. The data indicated that the risk of exposure locally within an endemic region may vary widely and tentatively suggested that a threshold density of bank voles might be necessary to achieve before effective spread of Puumala virus within the rodent population may occur.There is no firm evidence of the occurrence of Puumala virus among wild living animals other than rodents. A study of Swedish moose, an animal which is ecologically well characterized, was performed. Convincing evidence of past Puumala virus infection was found in 5/260 moose originating from Puumala virus-endemic areas but in none of 167 animals from nonendemic areas. Based on the low seroprevalence recorded, moose seemed to serve as endstage hosts rather than being active parts of the enzootic circle of transmission.In conclusion, the present investigations confirmed that the exposure to Puumala virus is geographically well restricted in Sweden. Seroprevalence studies indicated that only a minor proportion of individuals infected with Puumala virus are clinically reported, with a bias in favour of men. NE was confirmed to occur in children, with a clinical picture similar to that of adults. An occupational risk was defined for acquisition of Puumala virus infection. Studies in rodents suggested that there may be wide local variations within a limited area in the risk of exposure to Puumala virus. The studies validated the usefulness of a newly developed ELISA based on recombinant nucleocapsid peptides of hantaviruses and finally, methodological progress was reached when Puumala virus was, for the first time, successfully isolated from a Scandinavian patient.
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14. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Health problems and self-medication among Swedish travellers.
- 1994
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Ingår i: Scandinavian Journal of Infectious Diseases. - 0036-5548 .- 1651-1980. ; 26:6, s. 711-7
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Tidskriftsartikel (refereegranskat)abstract
- 500 consecutive travellers seeking pre-travel health advice were issued a questionnaire before leaving Sweden to continuously record health problems and use of medication during travel. Of 442 subjects who turned in assessable questionnaires (232 male and 210 female, mean age 37 years), 81% travelled to areas at high risk for the acquisition of diarrhea. The mean duration of travel was 4 weeks. During travel 218 (49% at 95% CI 44.3 to 53.7%) of the travellers experienced some illness and 61 (14%) had symptoms of more than one illness. The mean duration of illness was 4.5 days, and 65 subjects (30% of ill travellers) were confined to bed for a mean duration of 2 days. The incidence of illness was significantly (p < 0.01) higher among travellers to high risk than to low risk areas (55% vs 26%), among young travellers than among elderly (65% vs 33%), and among those going on adventure tours compared with recreational tourists (74% vs 41%). Diarrhea was reported by 36% (95% CI 31.6 to 40.5%), and respiratory tract infection by 21% (95% CI 17.2 to 24.8%). Self-medication with one or several drugs was initiated by 163 (75%) travellers experiencing illness during travel. Thus, every second Swedish traveller to tropical and subtropical areas experienced some kind of travel-related, often incapacitating, health problem.
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15. |
- Ahlm, Clas, 1956-, et al.
(författare)
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High prevalence of hantavirus antibodies in bank voles (Clethrionomys glareolus) captured in the vicinity of households afflicted with nephropathia epidemica.
- 1997
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Ingår i: American Journal of Tropical Medicine and Hygiene. - 0002-9637 .- 1476-1645. ; 56:6, s. 674-8
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Tidskriftsartikel (refereegranskat)abstract
- Puumala virus, the causative agent of nephropathia epidemica (NE), occurs endemically in Europe and is spread mainly by the bank vole (Clethrionomys glareolus). In the vicinity of each of four households afflicted with NE, we studied rodents with regard to population density and prevalence of Puumala virus-specific antibodies. For each case area, a control area was randomly selected 10 km away, without regard to the presence of human settlement. During 6,000 trap nights, 328 rodents were caught, of which 299 were C. glareolus. The mean rodent densities of case and control areas were 6.6 and 3.7 animals per 100 trap nights (P < 0.001). The prevalence of serum antibodies was 15.9% in case areas compared with 5.6% in control areas (P < 0.05). In three of the case areas, where NE had occurred 3-10 weeks before trapping, the rodent density and seroprevalence were much higher than in the fourth area, where NE occurred 38 weeks before trapping. In conclusion, C. glareolus seropositive for Puumala virus occurred more frequently near households afflicted with NE than in control areas 10 km away.
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16. |
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17. |
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18. |
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19. |
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20. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Nephropathia epidemica (hemorrhagic fever with renal syndrome) in children : clinical characteristics.
- 1994
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Ingår i: The Pediatric Infectious Disease Journal. - 0891-3668 .- 1532-0987. ; 13:1, s. 45-9
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Tidskriftsartikel (refereegranskat)abstract
- The clinical characteristics of serologically verified nephropathia epidemica, the Scandinavian form of hemorrhagic fever with renal syndrome, were studied in Swedish children who were < 15 years of age. In 1990 to 1992, 14 cases were prospectively followed. A retrospective survey during 1984 to 1990 disclosed another 18 cases. Among the 32 cases (20 boys, 12 girls, 3 to 15 years of age; median age, 11 years), the most common symptoms were fever (100%), headache (100%), abdominal pain (93%), vomiting (91%) and back pain (76%). Laboratory findings included elevated serum creatinine concentration (19 of 28) and thrombocytopenia (7 of 22). Urinalysis showed proteinuria (31 of 31 patients) and hematuria (24 of 30). Six children had mild hemorrhagic manifestations (epistaxis, metrorrhagia, and petechiae). No severe complications occurred. The clinical symptoms of children with nephropathia epidemica seem to be similar to those found among adult nephropathia epidemica cases.
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21. |
- Ahlm, Clas
(författare)
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Norrländska infektionssjukdomar
- 2011. - 5
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Ingår i: Infektionssjukdomar. - Sundbyberg : Säve förlag.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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22. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Prevalence of antibodies specific to Puumala virus among farmers in Sweden
- 1998
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 24:2, s. 104-108
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Tidskriftsartikel (refereegranskat)abstract
- Serological evidence confirmed that the exposure of humans to Puumala virus is firmly restricted to the northern and central parts of Sweden. In addition the evidence indicated that, in this region, farming is associated with an increased risk of contracting hantavirus infection.
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23. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Prevalence of serum antibodies to hantaviruses in northern Sweden as measured by recombinant nucleocapsid proteins.
- 1997
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 29:4, s. 349-54
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Tidskriftsartikel (refereegranskat)abstract
- An enzyme-linked immunosorbent assay (ELISA) based on recombinant nucleocapsid protein (rN delta) (aa 1-117) of Hantaan, Seoul, Dobrava, Sin Nombre and Puumala hantaviruses was used to determine the prevalence of antibodies among randomized and stratified individuals from northern Sweden. In total, 137/1533 individuals (8.9%) had specific serum IgG antibodies to Puumala virus, the only hantavirus known to occur in the region. The prevalence of antibodies to Puumala virus (8.9%) was determined to be higher than previously reported (5.4%) in the same serum material, by use of immunofluorescence assay. As expected, sera reactive to Puumala virus rN delta did frequently cross-react with Sin Nombre virus protein. Unexpectedly, 21/1533 (1.4%) individuals recognized the Sin Nombre virus rN delta exclusively. Another 8 subjects showed reactivity in the ELISA to Hantaan, Seoul, or Dobrava virus-derived rN delta but not Puumala virus or Sin Nombre virus rN delta. The present demonstration in some individuals of antibodies specifically recognizing the Sin Nombre, Dobrava, Hantaan and Seoul virus protein justifies an awareness of the possibility that hantaviruses antigenically different from Puumala virus might occur in the region.
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24. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Prevalence of serum IgG antibodies to Puumala virus (haemorrhagic fever with renal syndrome) in northern Sweden.
- 1994
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Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 113:1, s. 129-36
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Tidskriftsartikel (refereegranskat)abstract
- A stratified and randomly-selected population sample was identified in 1990 in order to study the seroprevalence of nephropathia epidemica (haemorrhagic fever with renal syndrome) in Northern Sweden. Sera from 1538 subjects (750 men, 788 women), 25-64 years of age, were analysed for the presence of Puumala virus (PUV) specific-IgG by the indirect immunofluorescence antibody test. Specific IgG was detected in sera from 83 subjects (5.4%). Men and women had similar seroprevalence rates. The highest seroprevalences were found in subjects 55 years or older (8.0%) and among farmers and forestry workers (15.9%). The geographic distribution of seropositive individuals was uneven and there were significantly more seropositive persons in rural than in urban areas (P < 0.05).
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25. |
- Ahlm, Clas, 1956-, et al.
(författare)
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Serologic evidence of Puumala virus infection in wild moose in northern Sweden
- 2000
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Ingår i: American Journal of Tropical Medicine and Hygiene. - : American Society of Tropical Medicine and Hygiene. - 0002-9637 .- 1476-1645. ; 62:1, s. 106-111
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Tidskriftsartikel (refereegranskat)abstract
- Puumala (PUU) virus is the causative agent of nephropathia epidemica, the Scandinavian form of hemorrhagic fever with renal syndrome. The infection is acquired by airborne transmission of PUU virus from its rodent reservoir, the bank vole. Besides serologic data indicating that the virus may spread also to heterologous rodents, there is little information on the susceptibility of wild living animals to PUU virus. We studied the occurrence of antibodies to PUU virus in serum samples from 427 wild-living moose, of which 260 originated from the PUU virus-endemic northern and central parts of Sweden and 167 originated from the southern, nonendemic part of Sweden. Samples from 5 animals showed reactivity in an ELISA for recombinant PUU virus nucleocapsid protein, an immunofluorescent assay, and a neutralization test. These 5 animals all originated from the PUU virus-endemic northern part of Sweden. In conclusion, 5 of 260 moose from the endemic region showed convincing serologic evidence of past PUU virus infection. The seroprevalence was low, suggesting that the moose is subjected to endstage infection rather than being part of an enzootic transmission cycle.
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26. |
- Ahlm, Clas, et al.
(författare)
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Seroprevalence of Sindbis virus and associated risk factors in northern Sweden
- 2014
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Ingår i: Epidemiology and Infection. - : Cambridge University Press. - 0950-2688 .- 1469-4409. ; 142:7, s. 1559-1565
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Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne Sindbis virus (SINV) cause disease characterized by rash, fever and arthritis which often leads to long-lasting arthralgia. To determine the seroprevalence of SINV and associated risk factors in northern Sweden, a randomly selected population aged between 25 and 74 years were invited to join the MONICA study. Serum from 1611 samples were analysed for specific IgG antibodies. Overall, 2·9% had IgG against SINV. More men (3·7%) than women (2·0%) were SINV seropositive (P = 0·047) and it was more common in subjects with a lower educational level (P = 0·013) and living in small, rural communities (P < 0·001). Seropositivity was associated with higher waist circumference (P = 0·1), elevated diastolic blood pressure (P = 0·037), and history of a previous stroke (P = 0·011). In a multiple logistic regression analysis, adjusting for known risk factors for stroke, seropositivity for SINV was an independent predictor of having had a stroke (odds ratio 4·3, 95% confidence interval 1·4–13·0,P = 0·011).
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27. |
- Ahmad, Irma, et al.
(författare)
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High prevalence of persistent symptoms and reduced health-related quality of life 6 months after COVID-19
- 2023
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Ingår i: Frontiers in Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The long-term sequelae after COVID-19 constitute a challenge to public health and increased knowledge is needed. We investigated the prevalence of self-reported persistent symptoms and reduced health-related quality of life (HRQoL) in relation to functional exercise capacity, 6 months after infection, and explored risk factors for COVID-19 sequalae.METHODS: This was a prospective, multicenter, cohort study including 434 patients. At 6 months, physical exercise capacity was assessed by a 1-minute sit-to-stand test (1MSTST) and persistent symptoms were reported and HRQoL was evaluated through the EuroQol 5-level 5-dimension (EQ-5D-5L) questionnaire. Patients with both persistent symptoms and reduced HRQoL were classified into a new definition of post-acute COVID syndrome, PACS+. Risk factors for developing persistent symptoms, reduced HRQoL and PACS+ were identified by multivariable Poisson regression.RESULTS: Persistent symptoms were experienced by 79% of hospitalized, and 59% of non-hospitalized patients at 6 months. Hospitalized patients had a higher prevalence of self-assessed reduced overall health (28 vs. 12%) and PACS+ (31 vs. 11%). PACS+ was associated with reduced exercise capacity but not with abnormal pulse/desaturation during 1MSTST. Hospitalization was the most important independent risk factor for developing persistent symptoms, reduced overall health and PACS+.CONCLUSION: Persistent symptoms and reduced HRQoL are common among COVID-19 survivors, but abnormal pulse and peripheral saturation during exercise could not distinguish patients with PACS+. Patients with severe infection requiring hospitalization were more likely to develop PACS+, hence these patients should be prioritized for clinical follow-up after COVID-19.
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28. |
- Ahmed Hassan Ahmed, Osama, 1972-
(författare)
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Rift Valley fever : challenges and new insights for prevention and control using the “One Health” approach
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rift Valley fever (RVF) is an emerging viral zoonosis that causes frequent outbreaks in east Africa and on the Arabian Peninsula. The likelihood of RVF global expansion due to climate change and human anthropogenic factors is an important issue. The causative agent, RVF virus, is an arbovirus that is transmitted by several mosquito species and is able to infect a wide range of livestock as well as people. The infection leads to mass abortions and death in livestock and a potentially deadly hemorrhagic fever in humans. RVF has severe socio-economic consequences such as animal trade bans between countries, disruption of food security, and economic disaster for farmers and pastoralists as well as for countries. Human behavior such as direct contact with infected animals or their fluids and exposure to mosquito bites increases the risk for contracting the disease.To better understand the challenges associated with RVF outbreaks and to explore prevention and control strategies, we used the One Health approach. The local community had to be involved to understand the interaction between the environment, animals, and humans. We focused on Sudan, Saudi Arabia, and Kenya. First, we systematically reviewed the literature and then we performed cross sectional community-based studies using a special One Health questionnaire. Climatic and remote sensing data were used in combination with statistics to develop a sub-region predictive model for RVF.For both Saudi Arabia and Sudan, the ecology and environment of the affected areas were similar. These areas included irrigation canals and excessive rains that provide an attractive habitat for mosquito vectors to multiply. The surveillance systems were unable to detect the virus in livestock before it spread to humans. Ideally, livestock should serve as sentinels to prevent loss of human lives, but the situation here was reversed. Differences between countries regarding further spread of RVF was mainly determined by better economic and infrastructure resources.In Sudan, there was a lack of knowledge and appropriate practices at the studied community regarding RVF disease symptoms and risk factors for both animals and humans. The community was hesitant in notifying the authorities about RVF suspicion in livestock due to the lack of a compensation system. The perceived role of the community in controlling RVF was fragmented, increasing the probability of RVF transmission and disease.In Kenya, our study found that better knowledge about RVF does not always translate to more appropriate practices that avoid exposure to the disease. However, the combination of good knowledge, attitudes, and practices may explain why certain communities were less affected. Strategies to combat RVF should consider socio-cultural and behavioral differences among communities. We also noticed that RVF outbreaks in Kenya occurred in regions with high livestock density exposed to heavy rains and wet soil fluxes, which could be measured by evapotranspiration and vegetation seasonality variables. We developed a RVF risk map on a sub-regional scale. Future outbreaks could be better managed if such relevant RVF variables are integrated into early warning systems.To confront RVF outbreaks, a policy is needed that better incorporates ecological factors and human interactions with livestock and environment that help the RVF pathogen spread. Early detection and notification of RVF is essential because a delay will threaten the core of International Health Regulations (IHR), which emphasizes the share of information during a transboundary disease outbreak to avoid unnecessary geographical expansion.
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29. |
- Alexeyev, O A, et al.
(författare)
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Elevated levels of total and Puumala virus-specific immunoglobulin E in the Scandinavian type of hemorrhagic fever with renal syndrome.
- 1994
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Ingår i: Clinical and diagnostic laboratory immunology. - 1071-412X. ; 1:3, s. 269-72
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, it was reported that the total immunoglobulin E (IgE) level was increased in patients with hemorrhagic fever with renal syndrome (HFRS). The aim of the present study was to investigate whether specific IgE is synthesized during the course of the disease. For this purpose, an epsilon-capture enzyme-linked immunosorbent assay was developed. A total of 72 patients with HFRS caused by Puumala virus were studied. Three different control groups were included: 20 blood donors, 20 patients with other viral diseases (influenza A and B virus, acute Epstein-Barr virus, and acute cytomegalovirus infections), and 5 subjects with high levels of total IgE (median, 1,070 kU/liter; range, 773 to 5,740 kU/liter). The levels of total IgE were significantly higher during the acute phase of HFRS than those of blood donors (P < 0.01) and of patients with other viral diseases (P < 0.001). All patients developed a specific IgE response (median, 55 arbitrary units; range 24 to 123 arbitrary units) in the acute phase of the disease, whereas in the different control groups no specific IgE was detectable. Both total and specific IgE levels decreased during convalescence compared with those during the acute phase of HFRS (P < 0.001 and P < 0.001, respectively). In conclusion, we have shown that both total and specific IgE levels are increased in patients with HFRS compared with levels in patients with other viral diseases. The possible pathogenetic role of the specific IgE response in HFRS is discussed.
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30. |
- Alexeyev, O A, et al.
(författare)
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Hantavirus antigen detection using human serum immunoglobulin M as the capturing antibody in an enzyme-linked immunosorbent assay.
- 1996
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Ingår i: American Journal of Tropical Medicine and Hygiene. - 0002-9637 .- 1476-1645. ; 54:4, s. 367-71
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Tidskriftsartikel (refereegranskat)abstract
- An enzyme-linked immunosorbent assay (ELISA) was developed to detect different hantavirus antigens in cell culture; i.e. Puumala (PUU), Hantaan (HTN), and Dobrava (DOB) viruses. The assay was based on binding human serum immunoglobulin M (IgM) antibodies to the solid phase by use of goat anti-IgM antibodies. The captured IgM antibodies were present in the acute phase serum from two patients: one infected in Sweden and the other in Bosnia. Antigens being bound to the solid phase by the human anti-PUU and anti-DOB/HTN IgM antibodies were detected by a broadly reacting polyclonal rabbit anti PUU-recombinant nucleocapsid protein antiserum. The IgM isotype was proven to be at least five times more efficient than IgG when used as the capturing antibody. The sensitivity of the PUU antigen ELISA was approximately 0.5 ng/ml, as measured by titration with a PUU recombinant nucleoprotein antigen. Cell-associated PUU antigen in tissue culture was seen after 48 hr by the PUU-ELISA and after 96 hr by immunofluorescent assay. When tested for capacity to discriminate between PUU, DOB, and HTN viruses, significant differences were found: the Swedish serum detected PUU antigen at high titers, whereas no reactivity was found against DOB and HTN; the Bosnian serum detected both DOB and HTN at high titers but had a low reactivity to PUU. The method was also tested for its usefulness in detecting PUU antigen in bank vole (clethrionomys glareolus) lungs. Of 59 animals captured from the surroundings of patients with nephropathia epidemica, three became positive with a high activity in the PUU-ELISA, but with low reactivity in the DOB/HTN-ELISA. It is concluded that a sensitive ELISA has been developed to detect different hantaviruses in cell culture and lungs of bank voles.
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31. |
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32. |
- Alm, Erik, et al.
(författare)
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Universal Single-Probe RT-PCR Assay for Diagnosis of Dengue Virus Infections
- 2014
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Ingår i: PLoS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2727 .- 1935-2735. ; 8:12, s. e3416-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dengue is a mosquito-borne viral disease that has become more prevalent in the last few decades. Most patients are viremic when they present with symptoms, and early diagnosis of dengue is important in preventing severe clinical complications associated with this disease and also represents a key factor in differential diagnosis. Here, we designed and validated a hydrolysis-probe-based one-step real-time RT-PCR assay that targets the genomes of dengue virus serotypes 1-4. Methodology/Principal Findings: The primers and probe used in our RT-PCR assay were designed to target the 39 untranslated region of all complete genome sequences of dengue virus available in GenBank (n=3,305). Performance of the assay was evaluated using in vitro transcribed RNA, laboratory-adapted virus strains, external control panels, and clinical specimens. The linear dynamic range was found to be 10(4)-10(11) GCE/mL, and the detection limit was between 6.0x10(2) and 1.1x10(3) GCE/mL depending on target sequence. The assay did not cross-react with human RNA, nor did it produce false-positive results for other human pathogenic flaviviruses or clinically important etiological agents of febrile illnesses. We used clinical serum samples obtained from returning travelers with dengue-compatible symptomatology (n = 163) to evaluate the diagnostic relevance of our assay, and laboratory diagnosis performed by the RT-PCR assay had 100% positive agreement with diagnosis performed by NS1 antigen detection. In a retrospective evaluation including 60 archived serum samples collected from confirmed dengue cases 1-9 days after disease onset, the RT-PCR assay detected viral RNA up to 9 days after appearance of symptoms. Conclusions/Significance: The validation of the RT-PCR assay presented here indicates that this technique can be a reliable diagnostic tool, and hence we suggest that it be introduced as the method of choice during the first 5 days of dengue symptoms.
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33. |
- Amada, Takako, et al.
(författare)
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Development of an immunochromatography strip test based on truncated nucleocapsid antigens of three representative hantaviruses
- 2014
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Ingår i: Virology Journal. - 1743-422X. ; 11, s. 87-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hantaviruses are causative agents of hemorrhagic fever with renal syndrome (HFRS) and nephropathia epidemica (NE) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. There is a need for time-saving diagnostic methods. In the present study, recombinant N antigens were used as antigens in an immunochromatography strip (ICG) test to detect specific IgG antibodies. Methods: The N-terminal 103 amino acids (aa) of Hantaan virus (HTNV), Puumala virus (PUUV) and Andes virus (ANDV) nucleocapsid (N) protein were expressed in E. coli as representative antigens of three groups (HFRS, NE and HPS-causing viruses) of hantavirus. Five different types of ICG test strips, one antigen line on one strip for each of the three selected hantaviruses (HTNV, PUUV and ANDV), three antigen lines on one strip and a mixed antigen line on one strip, were developed and sensitivities were compared. Results: A total of 87 convalescent-phase patient sera, including sera from 35 HFRS patients, 36 NE patients and 16 HPS patients, and 25 sera from healthy seronegative people as negative controls were used to evaluate the ICG test. Sensitivities of the three-line strip and mixed-line strip were similar to those of the single antigen strip (97.2 to 100%). On the other hand, all of the ICG test strips showed high specificities to healthy donors. Conclusion: These results indicated that the ICG test with the three representative antigens is an effective serodiagnostic tool for screening and typing of hantavirus infection in humans.
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34. |
- Baharom, Faezzah, et al.
(författare)
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Dendritic Cells and Monocytes with Distinct Inflammatory Responses Reside in Lung Mucosa of Healthy Humans
- 2016
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 196:11, s. 4498-4509
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Tidskriftsartikel (refereegranskat)abstract
- Every breath we take contains potentially harmful pathogens or allergens. Dendritic cells (DCs), monocytes, and macrophages are essential in maintaining a delicate balance of initiating immunity without causing collateral damage to the lungs because of an exaggerated inflammatory response. To document the diversity of lung mononuclear phagocytes at steady-state, we performed bronchoscopies on 20 healthy subjects, sampling the proximal and distal airways (bronchial wash and bronchoalveolar lavage, respectively), as well as mucosal tissue (endobronchial biopsies). In addition to a substantial population of alveolar macrophages, we identified subpopulations of monocytes, myeloid DCs (MDCs), and plasmacytoid DCs in the lung mucosa. Intermediate monocytes and MDCs were highly frequent in the airways compared with peripheral blood. Strikingly, the density of mononuclear phagocytes increased upon descending the airways. Monocytes from blood and airways produced 10-fold more proinflammatory cytokines than MDCs upon ex vivo stimulation. However, airway monocytes were less inflammatory than blood monocytes, suggesting a more tolerant nature. The findings of this study establish how to identify human lung mononuclear phagocytes and how they function in normal conditions, so that dysregulations in patients with respiratory diseases can be detected to elucidate their contribution to immunity or pathogenesis.
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35. |
- Baharom, Faezzah, et al.
(författare)
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Human lung dendritic cells : spatial distribution and phenotypic identification in endobronchial biopsies using immunohistochemistry and flow cytometry
- 2017
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Ingår i: Journal of Visualized Experiments. - Cambridge : MyJoVE Corp.. - 1940-087X. ; :119
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Tidskriftsartikel (refereegranskat)abstract
- The lungs are constantly exposed to the external environment, which in addition to harmless particles, also contains pathogens, allergens, and toxins. In order to maintain tolerance or to induce an immune response, the immune system must appropriately handle inhaled antigens. Lung dendritic cells (DCs) are essential in maintaining a delicate balance to initiate immunity when required without causing collateral damage to the lungs due to an exaggerated inflammatory response. While there is a detailed understanding of the phenotype and function of immune cells such as DCs in human blood, the knowledge of these cells in less accessible tissues, such as the lungs, is much more limited, since studies of human lung tissue samples, especially from healthy individuals, are scarce. This work presents a strategy to generate detailed spatial and phenotypic characterization of lung tissue resident DCs in healthy humans that undergo a bronchoscopy for the sampling of endobronchial biopsies. Several small biopsies can be collected from each individual and can be subsequently embedded for ultrafine sectioning or enzymatically digested for advanced flow cytometric analysis. The outlined protocols have been optimized to yield maximum information from small tissue samples that, under steady-state conditions, contain only a low frequency of DCs. While the present work focuses on DCs, the methods described can directly be expanded to include other (immune) cells of interest found in mucosal lung tissue. Furthermore, the protocols are also directly applicable to samples obtained from patients suffering from pulmonary diseases where bronchoscopy is part of establishing the diagnosis, such as chronic obstructive pulmonary disease (COPD), sarcoidosis, or lung cancer.
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36. |
- Baudin, Maria, 1982-, et al.
(författare)
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Association of Rift Valley fever virus infection with miscarriage in Sudanese women : a cross-sectional study
- 2016
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Ingår i: The Lancet Global Health. - 2214-109X. ; 4:11, s. e864-e871
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rift Valley fever virus is an emerging mosquito-borne virus that causes infections in animals and human beings in Africa and the Arabian Peninsula. Outbreaks of Rift Valley fever lead to mass abortions in livestock, but such abortions have not been identified in human bezings. Our aim was to investigate the cause of miscarriages in febrile pregnant women in an area endemic for Rift Valley fever.METHODS: Pregnant women with fever of unknown origin who attended the governmental hospital of Port Sudan, Sudan, between June 30, 2011, and Nov 17, 2012, were sampled at admission and included in this cross-sectional study. Medical records were retrieved and haematological tests were done on patient samples. Presence of viral RNA as well as antibodies against a variety of viruses were analysed. Any association of viral infections, symptoms, and laboratory parameters to pregnancy outcome was investigated using Pearson's χ(2) test.FINDINGS: Of 130 pregnant women with febrile disease, 28 were infected with Rift Valley fever virus and 31 with chikungunya virus, with typical clinical and laboratory findings for the infection in question. 15 (54%) of 28 women with an acute Rift Valley fever virus infection had miscarriages compared with 12 (12%) of 102 women negative for Rift Valley fever virus (p<0·0001). In a multiple logistic regression analysis, adjusting for age, haemorrhagic disease, and chikungunya virus infection, an acute Rift Valley fever virus infection was an independent predictor of having a miscarriage (odds ratio 7·4, 95% CI 2·7-20·1; p<0·0001).INTERPRETATION: This study is the first to show an association between infection with Rift Valley fever virus and miscarriage in pregnant women. Further studies are warranted to investigate the possible mechanisms. Our findings have implications for implementation of preventive measures, and evidence-based information to the public in endemic countries should be strongly recommended during Rift Valley fever outbreaks.FUNDING: Schlumberger Faculty for the Future, CRDF Global (31141), the Swedish International Development Cooperation Agency, the County Council of Västerbotten, and the Faculty of Medicine, Umeå University.
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37. |
- Baudin, Maria, 1982-
(författare)
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Rift Valley fever : consequences of virus-host interactions
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rift Valley fever virus (RVFV) is a mosquito-borne virus which has the ability to infect a large variety of animals including humans in Africa and Arabian Peninsula. The abortion rate among these animals are close to 100%, and young animals develop severe disease which often are lethal.In humans, Rift Valley fever (RVF) presents in most cases as a mild illness with influenza-like symptoms. However, in about 8% of the cases it progresses into a more severe disease with a high case fatality rate. Since there is such a high abortion rate among infected animals, a link between human miscarriage and RVFV has been suggested, but never proven.We could in paper I for the first time show an association between acute RVFV infection and miscarriage in humans. We observed an increase in pregnant women arriving at the Port Sudan Hospital with fever of unknown origin, and several of the patients experienced miscarriage. When we analysed their blood samples for several viral diseases we found that many had an acute RVFV infection and of these, 54% experienced a miscarriage. The odds of having a miscarriage was 7 times higher for RVFV patients compared to the RVFV negative women of which only 12% miscarried. These results indicated that RVFV infection could be a contributing factor to miscarriage.RVFV is an enveloped virus containing the viral glycoproteins n and c (Gn and Gc respectively), where Gn most likely is responsible for the initial cellular contact. The protein DC-SIGN on dendritic cells and the glycosaminoglycan heparan sulfate has been suggested as cellular receptors for RVFV, however other mechanisms are probably also involved in binding and entry. Charge is a driving force for molecular interaction and has been shown to be important for cellular attachment of several viruses, and in paper II we could show that when the charge around the cells was altered, the infection was affected. We also showed that Gn most likely has a positive charge at a physiological pH.When we added negatively charged molecules to the viral particles before infection, we observed a decreased infection efficiency, which we also observed after removal of carbohydrate structures from the cell surface.Our results suggested that the cellular interaction partner for initial attachment is a negatively charged carbohydrate. Further investigations into the mechanisms of RVFV cellular interactions has to be undertaken in order to understand, and ultimately prevent, infection and disease.There is currently no vaccine approved for human use and no specific treatments for RVF, so there is a great need for developing safe effective drugs targeting this virus. We designed a whole-cell based high-throughput screen (HTS) assay which we used to screen libraries of small molecular compounds for anti-RVFV properties. After dose-response and toxicity analysis of the initial hits, we identified six safe and effective inhibitors of RVFV infection that with further testing could become drug candidates for treatment of RVF. This study demonstrated the application of HTS using a whole-cell virus replication reporter gene assay as an effective method to identify novel compounds with potential antiviral activity against RVFV.
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38. |
- Bergqvist, Joakim, et al.
(författare)
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Detection and Isolation of Sindbis Virus from Mosquitoes Captured During an Outbreak in Sweden, 2013
- 2015
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:2, s. 133-140
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Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne alphaviruses have the potential to cause large outbreaks throughout the world. Here we investigated the causative agent of an unexpected Sindbis virus (SINV) outbreak during August-September, 2013, in a previously nonendemic region of Sweden. Mosquitoes were collected using carbon dioxide-baited CDC traps at locations close to human cases. The mosquitoes were initially screened as large pools by SINV-specific quantitative RT-PCR, and the SINV-positive mosquitoes were species determined by single-nucleotide polymorphism (SNP) analysis, followed by sequencing the barcoding region of the cytochrome oxidase I gene. The proportion of the collected mosquitoes was determined by a metabarcoding strategy. By using novel strategies for PCR screening and genetic typing, a new SINV strain, Lovanger, was isolated from a pool of 1600 mosquitoes composed of Culex, Culiseta, and Aedes mosquitoes as determined by metabarcoding. The SINV-positive mosquito Culiseta morsitans was identified by SNP analysis and sequencing. After whole-genome sequencing and phylogenetic analysis, the SINV Lovanger isolate was shown to be most closely similar to recent Finnish SINV isolates. In conclusion, within a few weeks, we were able to detect and isolate a novel SINV strain and identify the mosquito vector during a sudden SINV outbreak.
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39. |
- Bergstedt Oscarsson, Kristina, et al.
(författare)
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Human Puumala hantavirus infection in northern Sweden : increased seroprevalence and association to risk and health factors
- 2016
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Ingår i: BMC Infectious Diseases. - : Springer Science and Business Media LLC. - 1471-2334. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The rodent borne Puumala hantavirus (PUUV) causes haemorrhagic fever with renal syndrome in central and northern Europe. The number of cases has increased and northern Sweden has experienced large outbreaks in 1998 and 2006-2007 which raised questions regarding the level of immunity in the human population.METHODS: A randomly selected population aged between 25 and 74 years from northern Sweden were invited during 2009 to participate in a WHO project for monitoring of trends and determinants in cardiovascular disease. Health and risk factors were evaluated and sera from 1,600 participants were available for analysis for specific PUUV IgG antibodies using a recombinant PUUV nucleocapsid protein ELISA.RESULTS: The overall seroprevalence in the investigated population was 13.4 %, which is a 50 % increase compared to a similar study only two decades previously. The prevalence of PUUV IgG increased with age, and among 65-75 years it was 22 %. More men (15.3 %) than women (11.4 %) were seropositive (p < 0.05). The identified risk factors were smoking (OR = 1.67), living in rural areas (OR = 1.92), and owning farmland or forest (OR = 2.44). No associations were found between previous PUUV exposure and chronic lung disease, diabetes, hypertension, renal dysfunction, stroke or myocardial infarction.CONCLUSIONS: PUUV is a common infection in northern Sweden and there is a high life time risk to acquire PUUV infection in endemic areas. Certain risk factors as living in rural areas and smoking were identified. Groups with increased risk should be targeted for future vaccination when available, and should also be informed about appropriate protection from rodent secreta.
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40. |
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41. |
- Björkström, Niklas K, et al.
(författare)
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Rapid expansion and long-term persistence of elevated NK cell numbers in humans infected with hantavirus
- 2011
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 208:1, s. 13-21
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Tidskriftsartikel (refereegranskat)abstract
- Natural killer (NK) cells are known to mount a rapid response to several virus infections. In experimental models of acute viral infection, this response has been characterized by prompt NK cell activation and expansion followed by rapid contraction. In contrast to experimental model systems, much less is known about NK cell responses to acute viral infections in humans. We demonstrate that NK cells can rapidly expand and persist at highly elevated levels for >60 d after human hantavirus infection. A large part of the expanding NK cells expressed the activating receptor NKG2C and were functional in terms of expressing a licensing inhibitory killer cell immunoglobulin-like receptor (KIR) and ability to respond to target cell stimulation. These results demonstrate that NK cells can expand and remain elevated in numbers for a prolonged period of time in humans after a virus infection. In time, this response extends far beyond what is considered normal for an innate immune response.
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42. |
- Björsell, Tove, et al.
(författare)
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Risk factors for impaired respiratory function post COVID-19 : A prospective cohort study of nonhospitalized and hospitalized patients
- 2023
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Ingår i: Journal of Internal Medicine. - : Wiley-Blackwell Publishing Inc.. - 0954-6820 .- 1365-2796. ; 293:5, s. 600-614
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Severe COVID-19 increases the risk for long-term respiratory impairment, but data after mild COVID-19 are scarce. Our aims were to determine risk factors for reduced respiratory function 3-6 months after COVID-19 infection and to investigate if reduced respiratory function would relate to impairment of exercise performance and breathlessness.METHODS: Patients with COVID-19 were enrolled at the University Hospitals of Umeå and Örebro, and Karlstad Central Hospital, Sweden. Disease severity was defined as mild (nonhospitalized), moderate (hospitalized with or without oxygen treatment), and severe (intensive care). Spirometry, including diffusion capacity (DLCO ), was performed 3-6 months after hospital discharge or study enrollment (for nonhospitalized patients). Breathlessness (defined as ≥1 according to the modified Medical Research Council scale) and functional exercise capacity (1-min sit-to-stand test; 1-MSTST) were assessed.RESULTS: Between April 2020 and May 2021, 337 patients were enrolled in the study. Forced vital capacity and DLCO were significantly lower in patients with severe COVID-19. Among hospitalized patients, 20% had reduced DLCO , versus 4% in nonhospitalized. Breathlessness was found in 40.6% of the participants and was associated with impaired DLCO . A pathological desaturation or heart rate response was observed in 17% of participants during the 1-MSTST. However, this response was not associated with reduced DLCO .CONCLUSION: Reduced DLCO was the major respiratory impairment 3-6 months following COVID-19, with hospitalization as the most important risk factor. The lack of association between impaired DLCO and pathological physiological responses to exertion suggests that these physiological responses are not primarily related to decreased lung function.
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43. |
- Blanco Penedo, Isabel, et al.
(författare)
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Seroepidemiology of Crimean-Congo Hemorrhagic Fever Virus (CCHFV) in cattle across three livestock pastoral regions in Kenya
- 2021
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Ingår i: Dairy. - : MDPI. - 2624-862X. ; 2:3, s. 425-434
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Tidskriftsartikel (refereegranskat)abstract
- Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonotic disease, endemic in Africa, with a high case fatality rate. There is no efficient treatment or licensed vaccine. This study aimed to determine the prevalence of CCHFV in cattle in extensive grazing systems (both pastoralism and ranching) within the Maasai Mara ecosystem, Nanyuki, and the Ol Pejeta Conservancy in Kenya. We conducted a seroepidemiological study of the sera of 148 cattle from 18 households from the three ecosystems in 2014, 2016, and 2019. Sera from 23 sheep and 17 goats were also obtained from the same households during the same period. Sera were analyzed for the presence of antibodies to CCHFV using the commercially available double-antigen ELISA kit. Overall, 31.5% CCHFV seropositivity was observed. The prevalence of CCHF was analyzed using a multiple logistic mixed model with main predictors. Risk factors associated with exposure to CCHFV were age (p = 0.000) and season (p = 0.007). Our findings suggest exposure to CCHFV and point to cattle as likely reservoirs of CCHFV in Kenya. The findings might play a role in providing better insights into disease risk and dynamics where analysis of tick populations in these regions should be further investigated.
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44. |
- Bortz, Robert H., et al.
(författare)
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Single-Dilution COVID-19 Antibody Test with Qualitative and Quantitative Readouts
- 2021
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Ingår i: mSphere. - : American Society for Microbiology. - 2379-5042. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- The coronavirus disease 2019 (COVID-19) global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to place an immense burden on societies and health care systems. A key component of COVID-19 control efforts is serological testing to determine the community prevalence of SARS-CoV-2 exposure and quantify individual immune responses to prior SARS-CoV-2 infection or vaccination. Here, we describe a laboratory-developed antibody test that uses readily available research-grade reagents to detect SARS-CoV-2 exposure in patient blood samples with high sensitivity and specificity. We further show that this sensitive test affords the estimation of viral spike-specific IgG titers from a single sample measurement, thereby providing a simple and scalable method to measure the strength of an individual's immune response. The accuracy, adaptability, and cost-effectiveness of this test make it an excellent option for clinical deployment in the ongoing COVID-19 pandemic.IMPORTANCE Serological surveillance has become an important public health tool during the COVID-19 pandemic. Detection of protective antibodies and seroconversion after SARS-CoV-2 infection or vaccination can help guide patient care plans and public health policies. Serology tests can detect antibodies against past infections; consequently, they can help overcome the shortcomings of molecular tests, which can detect only active infections. This is important, especially when considering that many COVID-19 patients are asymptomatic. In this study, we describe an enzyme-linked immunosorbent assay (ELISA)-based qualitative and quantitative serology test developed to measure IgG and IgA antibodies against the SARS-CoV-2 spike glycoprotein. The test can be deployed using commonly available laboratory reagents and equipment and displays high specificity and sensitivity. Furthermore, we demonstrate that IgG titers in patient samples can be estimated from a single measurement, enabling the assay's use in high-throughput clinical environments.
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45. |
- Braun, Monika, et al.
(författare)
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NK Cell Activation in Human Hantavirus Infection Explained by Virus-Induced IL-15/IL15R alpha Expression
- 2014
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 10:11, s. e1004521-
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Tidskriftsartikel (refereegranskat)abstract
- Clinical infection with hantaviruses cause two severe acute diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). These diseases are characterized by strong immune activation, increased vascular permeability, and up to 50% case-fatality rates. One prominent feature observed in clinical hantavirus infection is rapid expansion of natural killer (NK) cells in peripheral blood of affected individuals. We here describe an unusually high state of activation of such expanding NK cells in the acute phase of clinical Puumala hantavirus infection. Expanding NK cells expressed markedly increased levels of activating NK cell receptors and cytotoxic effector molecules. In search for possible mechanisms behind this NK cell activation, we observed virus-induced IL-15 and IL-15R alpha on infected endothelial and epithelial cells. Hantavirus-infected cells were shown to strongly activate NK cells in a cell-cell contact-dependent way, and this response was blocked with anti-IL-15 antibodies. Surprisingly, the strength of the IL-15-dependent NK cell response was such that it led to killing of uninfected endothelial cells despite expression of normal levels of HLA class I. In contrast, hantavirus-infected cells were resistant to NK cell lysis, due to a combination of virus-induced increase in HLA class I expression levels and hantavirus-mediated inhibition of apoptosis induction. In summary, we here describe a possible mechanism explaining the massive NK cell activation and proliferation observed in HFRS patients caused by Puumala hantavirus infection. The results add further insights into mechanisms behind the immunopathogenesis of hantavirus infections in humans and identify new possible targets for intervention.
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46. |
- Brorstad, Alette, et al.
(författare)
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Early diagnosis of hantavirus infection by family doctors can reduce inappropriate antibiotic use and hospitalization
- 2010
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Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 28:3, s. 179-184
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Tidskriftsartikel (refereegranskat)abstract
- Raised awareness in general practice regarding emerging infections and better diagnostic tools are desirable. This study of a Hantavirus outbreak shows that general practitioners are frontline doctors during outbreaks and through early and correct diagnosis they can reduce antibiotic treatment and hospitalization.
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47. |
- Brundin, Peik, et al.
(författare)
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Gene Expression of Estrogen Receptors in Pbmc From Patients With Puumala-Virus Infection
- 2012
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Ingår i: Shock. - Philadelphia : Lippincott Williams & Wilkins. - 1073-2322 .- 1540-0514. ; 37:4, s. 355-359
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Tidskriftsartikel (refereegranskat)abstract
- The influence of estrogen signaling on infectious diseases is not fully known. Males seem to be more susceptible to infections than females. This has also been noted for the Scandinavian form of hemorrhagic fever with renal syndrome caused by Puumala hantavirus (PUUV). To investigate the differences in estrogen receptors in relation to sex and clinical severity, 20 patients (10 males, 10 females) with confirmed PUUV infection were studied. Real-time polymerase chain reaction was performed for analyzing mRNA expression of estrogen receptor-alpha (ERV), ER beta, and ER beta 2 (ER beta cx) in peripheral blood mononuclear cells from patients and healthy age-and sex-matched blood donors. Blood chemistry and peripheral blood mononuclear cells sampling were performed during the acute and convalescent phases. None or very small amounts of ER beta were detected, and ER alpha and ER beta 2 mRNA were elevated in the patient group. The samples from the males were correlated with ER beta 2; the female samples, with ER alpha. Furthermore, the female and male samples are partly separated using multivariate statistic analysis (principal component analysis), supporting findings that clinical symptoms differ depending on sex.
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48. |
- Cagigi, Alberto, et al.
(författare)
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Airway antibodies emerge according to COVID-19 severity and wane rapidly but reappear after SARS-CoV-2 vaccination
- 2021
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Ingår i: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 6:22
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights into the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity, from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared with naive individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, although systemic IgG levels were durable for up to 8 months, airway IgG and IgA declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naive individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccinations for previously infected individuals to obtain optimal mucosal protection.
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49. |
- Cardell, Kristina, 1964-
(författare)
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Studies on Hepatitis B Vaccination and Factors Associated with the Vaccine Response
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hepatitis B virus causes liver disease and up to 2 billion people have been in contact with the virus world wide. It can cause both acute and chronic disease. The routes for transmission are through blood, mother to infant at time of delivery and sexually. Chronic hepatitis B infection is a risk factor for development of liver cirrhosis and hepatocellular carcinoma. Prevention of hepatitis B virus infection is highly desirable. Since the early1980s hepatitis B vaccine has been available. It can effectively prevent the disease and has been found to be safe. The World Health Organisation, WHO, has recommended all countries to implement the vaccine in their children’s vaccination programmes and many countries have followed this recommendation. In Sweden so far the recommendation is vaccination of identified risk groups for hepatitis B. Health care workers who are at risk of having blood contact in their work is one such risk group.In a large study on health care workers who were intradermally vaccinated with the hepatitis B vaccine, 960/1406 (68.3%) developed protective levels of antibodies to HBsAg (anti-HBs; defined as >10 mIU/mL) after three doses. After administering of an additional fourth dose to non-responders the response rate was 1187/1335 (88.9%). Risk factors for non-response were smoking and age above 40 years. Also, the vaccine response rates improved during the study and a risk of giving a too small dose with intradermal administration was also identified. This suggests that intradermal administration is dependent on well trained personnel.A genetic factor which has been proposed to be associated with a non-responder status to HBV vaccination is the HLA haplotype of the host. In a study in on 69 responders and 53 non-responders the haplotypes were therefore determined. It was found that [DQB1*0602; DQA1*0102; DR15] and [DQB1*0603; DQA1*0103; DRB1*1301] were more likely to be found in responders (p<0.025 and p<0.05 respectively). In non-responders the haplotype [DQB1*0604; DQA1*0102; DRB1*1302] was found more frequently (p<0.005). This study supports that the HLA class II of the host is involved in the ability to respond to the HBV vaccination.To further test the genetic link between the HLA of the host and a non-responder status, relatives to known intradermal non-responders with known haplotypes for DQA1, DQB1 and DRB1 were vaccinated in the same way, intradermally. The response rate in the relatives was 15/26 (58%) which is lower than expected suggesting a genetic influence on the vaccine response. In this study 5/6 with the haplotype [DQB1*0604; DQA1*0102; DRB1*1302] were non-responders which is in line with the previous data that this haplotype is correlated to hepatitis B vaccine non-response.Finally, to test a strategy by which we could induce an effective anti-HBs seroconversion in non-responders we revaccinated these with the combined hepatitis A and B vaccine intramuscularly at a double dose. Already after the first revaccination dose 26/44 (60%) responded with protective antibodies compared to 2/20 (10%) in a vaccine naïve reference group, suggesting an anamnestic response. After three doses 42/44 (95%) responded in the non-responder group and 20/20 (100%) in the reference group. All participants in the study responded to the hepatitis A antigen.In conclusion these studies show that intradermal vaccine administration can be used and is effective, and that the ability to respond is influenced by several, including genetic, factors. Importantly a non-responder status to hepatitis B vaccination is not absolute, a double dose of the combined HAV and HBV vaccine effectively overcomes this non-response in most individuals.
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50. |
- Connolly-Andersen, Anne-Marie, et al.
(författare)
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Endothelial activation and repair during hantavirus infection : association with disease outcome
- 2014
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Ingår i: Open forum infectious diseases. - : Oxford University Press (OUP). - 2328-8957. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Endothelial activation and dysfunction play a central role in the pathogenesis of sepsis and viral hemorrhagic fevers. Hantaviral disease is a viral hemorrhagic fever and is characterized by capillary dysfunction, although the underlying mechanisms for hantaviral disease are not fully elucidated.METHODS: The temporal course of endothelial activation and repair were analyzed during Puumala hantavirus infection and associated with disease outcome and a marker for hypoxia, insulin-like growth factor binding protein 1 (IGFBP-1). The following endothelial activation markers were studied: endothelial glycocalyx degradation (syndecan-1) and leukocyte adhesion molecules (soluble vascular cellular adhesion molecule 1, intercellular adhesion molecule 1, and endothelial selectin). Cytokines associated with vascular repair were also analyzed (vascular endothelial growth factor, erythropoietin, angiopoietin, and stromal cell-derived factor 1).RESULTS: Most of the markers we studied were highest during the earliest phase of hantaviral disease and associated with clinical and laboratory surrogate markers for disease outcome. In particular, the marker for glycocalyx degradation, syndecan-1, was significantly associated with levels of thrombocytes, albumin, IGFBP-1, decreased blood pressure, and disease severity.CONCLUSIONS: Hantaviral disease outcome was associated with endothelial dysfunction. Consequently, the endothelium warrants further investigation when designing future medical interventions.
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