| 1. |
- Khalil, Hussein, et al.
(author)
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The importance of bank vole density and rainy winters in predicting nephropathia epidemica incidence in Northern Sweden.
- 2014
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
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Journal article (peer-reviewed)abstract
- Pathogenic hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne viruses causing hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe, there are more than 10,000 yearly cases of nephropathia epidemica (NE), a mild form of HFRS caused by Puumala virus (PUUV). The common and widely distributed bank vole (Myodes glareolus) is the host of PUUV. In this study, we aim to explain and predict NE incidence in boreal Sweden using bank vole densities. We tested whether the number of rainy days in winter contributed to variation in NE incidence. We forecast NE incidence in July 2013-June 2014 using projected autumn vole density, and then considering two climatic scenarios: 1) rain-free winter and 2) winter with many rainy days. Autumn vole density was a strong explanatory variable of NE incidence in boreal Sweden in 1990-2012 (R2 = 79%, p<0.001). Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05). We report for the first time that risk of NE is higher in winters with many rainy days. Rain on snow and ground icing may block vole access to subnivean space. Seeking refuge from adverse conditions and shelter from predators, voles may infest buildings, increasing infection risk. In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014. Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.
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| 2. |
- Evander, Magnus, 1959-
(author)
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Detection of human papillomavirus : a study of normal cells, cervical intraepithelial neoplasia and cancer of the uterine cervix
- 1991
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Doctoral thesis (other academic/artistic)abstract
- Human papillomavirus (HPV) infections of the genital tract are now recognized to be among the most prevalent sexually transmitted diseases and also a contributing factor to some cancers of the lower genital tract of women and men. Presence of HPV in a clinical specimen is confined to detection of the HPV genome by DNA hybridization techniques.In this thesis, the commonly used DNA hybridization techniques Southern blot and filter in situ hybridization (FISH), were first used for detection of genital HPV infection. In order to increase and simplify the detection of HPV in clinical specimens a more sensitive technique, the polymerase chain reaction (PCR) was subsequently utilized.For type-specific amplificaiton of HPV 6, 16, 18 and 33 by PCR, oligonucleotide primers located in the E6 and E7 regions of the HPV genome were selected. They were found to specifically amplify the four types. To be able to amplify a broad spectrum of genital HPV types, general primers located in the E7 and El region of the HPV genome, were designed and evaluated. They were found to amplify a wide range of genital HPV types. To further increase the sensitivity and specificity, a two-step PCR using general primers, was assembled and evaluated against a one-step PCR on cervical scrapes from young women in a population-based study. The two-step PCR increased the sensitivity about three-fold compared to the one-step PCR.By Southern blot and FISH, 46% of women with abnormal Papanicolaou (Pap) smears were shown to carry HPV DNA. Of the women analysed by Southern blot, 39 % harboured HPV DNA and 25 % proved HPV 16 positive. Of the samples analysed with FISH, 27 % contained HPV DNA, compared to 11 % of samples from a group of reference women with normal cytology. With the Southern blot technique, HPV DNA was detected in 66% of women with cervical intraepithelial neoplasia grade III (CIN III) lesions. Fifty-four percent of the women with CIN III lesions were positive for HPV 16 DNA.By type-specific PCR, 12 out of 13 women with cervical squamous carcinoma were shown to carry HPV 16 and/or 18. Among women with adenosquamous carcinoma of the cervix, HPV 18 was the most prevalent type (26%) but HPV 16 was also found in a proportion of the women(15 %). Nine of 13 premenopausal cases with cervical adenocarcinoma were HPV positive compared to only 2 of 13 postmenopausal cases (p< 0.015). HPV 16 DNA was detected in 48%of women with cervical intraepithelial neoplasia (CIN), by the use of type-specific PCR.Three different groups of women with normal cytology were studied. Among women attending a family planning clinic in Kenya, 19% were shown to carry HPV virus, by the use of general primers. HPV 16 was found in 5.2% of these women and HPV 18 in 3.9%. In anothergroup of women, attending the gynecological department in Umeå, HPV 16 DNA was detected in 21 % by type-specific PCR. However, if consideration was taken to the medical status of the women, only 10% of women without any medical history were HPV 16 DNA positive, versus 54% of women with diseases and women with a relative progesterone dominance. Finally, by use of a two-step PCR using general primers, 20% of young women from Umeå taking part in a population-based study were demonstrated to carry HPV DNA. The most prevalent types were HPV 6 (2.0%) and HPV 16(2.7%). Among the women in this study with normal cytology, 19%were HPV positive.
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| 3. |
- Hassan, Osama Ahmed, et al.
(author)
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The 2007 rift valley Fever outbreak in Sudan
- 2011
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In: PLoS Neglected Tropical Diseases. - San Francisco, CA : Public Library of Science. - 1935-2727 .- 1935-2735. ; 5:9
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Research review (peer-reviewed)abstract
- Rift Valley fever (RVF) is a neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health and economy. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of animals. The virus is transmitted through bites from mosquitoes and exposure to viremic blood, body fluids, or tissues of infected animals. During 2007 a large RVF outbreak occurred in Sudan with a total of 747 confirmed human cases including 230 deaths (case fatality 30.8%); although it has been estimated 75,000 were infected. It was most severe in White Nile, El Gezira, and Sennar states near to the White Nile and the Blue Nile Rivers. Notably, RVF was not demonstrated in livestock until after the human cases appeared and unfortunately, there are no records or reports of the number of affected animals or deaths. Ideally, animals should serve as sentinels to prevent loss of human life, but the situation here was reversed. Animal contact seemed to be the most dominant risk factor followed by animal products and mosquito bites. The Sudan outbreak followed an unusually heavy rainfall in the country with severe flooding and previous studies on RVF in Sudan suggest that RVFV is endemic in parts of Sudan. An RVF outbreak results in human disease, but also large economic loss with an impact beyond the immediate influence on the directly affected agricultural producers. The outbreak emphasizes the need for collaboration between veterinary and health authorities, entomologists, environmental specialists, and biologists, as the best strategy towards the prevention and control of RVF.
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| 4. |
- Hassan, Osama Ahmed, 1972-, et al.
(author)
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The One Health approach to identify knowledge, attitudes and practices that affect community involvement in the control of Rift Valley fever outbreaks
- 2017
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In: PLoS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2727 .- 1935-2735. ; 11:2
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Journal article (peer-reviewed)abstract
- Rift Valley fever (RVF) is a viral mosquito-borne disease with the potential for global expansion, causes hemorrhagic fever, and has a high case fatality rate in young animals and in humans. Using a cross-sectional community-based study design, we investigated the knowledge, attitudes and practices of people living in small village in Sudan with respect to RVF outbreaks. A special One Health questionnaire was developed to compile data from 235 heads of household concerning their knowledge, attitudes, and practices with regard to controlling RVF. Although the 2007 RVF outbreak in Sudan had negatively affected the participants' food availability and livestock income, the participants did not fully understand how to identify RVF symptoms and risk factors for both humans and livestock. For example, the participants mistakenly believed that avoiding livestock that had suffered spontaneous abortions was the least important risk factor for RVF. Although the majority noticed an increase in mosquito population during the 2007 RVF outbreak, few used impregnated bed nets as preventive measures. The community was reluctant to notify the authorities about RVF suspicion in livestock, a sentinel for human RVF infection. Almost all the respondents stressed that they would not receive any compensation for their dead livestock if they notified the authorities. In addition, the participants believed that controlling RVF outbreaks was mainly the responsibility of human health authorities rather than veterinary authorities. The majority of the participants were aware that RVF could spread from one region to another within the country. Participants received most their information about RVF from social networks and the mass media, rather than the health system or veterinarians. Because the perceived role of the community in controlling RVF was fragmented, the probability of RVF spread increased.
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| 5. |
- Lindgren, Therese, 1977-, et al.
(author)
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Longitudinal analysis of the human T cell response during acute hantavirus infection
- 2011
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In: Journal of Virology. - Baltimore : American Society for Microbiology. - 0022-538X .- 1098-5514. ; 85:19, s. 10252-10260
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Journal article (peer-reviewed)abstract
- Longitudinal studies of T cell immune responses during viral infections in humans are essential for our understanding of how effector T cell responses develop, clear infection, and provide long-lasting immunity. Here, following an outbreak of a Puumala hantavirus infection in the human population, we longitudinally analyzed the primary CD8 T cell response in infected individuals from the first onset of clinical symptoms until viral clearance. A vigorous CD8 T cell response was observed early following the onset of clinical symptoms, determined by the presence of high numbers of Ki67(+)CD38(+)HLA-DR(+) effector CD8 T cells. This response encompassed up to 50% of total blood CD8 T cells, and it subsequently contracted in parallel with a decrease in viral load. Expression levels of perforin and granzyme B were high throughout the initial T cell response and likewise normalized following viral clearance. When monitoring regulatory components, no induction of regulatory CD4 or CD8 T cells was observed in the patients during the infection. However, CD8 as well as CD4 T cells exhibited a distinct expression profile of inhibitory PD-1 and CTLA-4 molecules. The present results provide insight into the development of the T cell response in humans, from the very onset of clinical symptoms following a viral infection to resolution of the disease.
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| 6. |
- Lwande, Olivia Wesula, et al.
(author)
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Global emergence of Alphaviruses that cause arthritis in humans
- 2015
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In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 5:1
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Journal article (peer-reviewed)abstract
- Arthropod-borne viruses (arboviruses) may cause severe emerging and re-emerging infectious diseases, which pose a significant threat to human and animal health in the world today. These infectious diseases range from mild febrile illnesses, arthritis, and encephalitis to haemorrhagic fevers. It is postulated that certain environmental factors, vector competence, and host susceptibility have a major impact on the ecology of arboviral diseases. Presently, there is a great interest in the emergence of Alphaviruses because these viruses, including Chikungunya virus, O'nyong'nyong virus, Sindbis virus, Ross River virus, and Mayaro virus, have caused outbreaks in Africa, Asia, Australia, Europe, and America. Some of these viruses are more common in the tropics, whereas others are also found in temperate regions, but the actual factors driving Alphavirus emergence and re-emergence remain unresolved. Furthermore, little is known about the transmission dynamics, pathophysiology, genetic diversity, and evolution of circulating viral strains. In addition, the clinical presentation of Alphaviruses may be similar to other diseases such as dengue, malaria, and typhoid, hence leading to misdiagnosis. However, the typical presence of arthritis may distinguish between Alphaviruses and other differential diagnoses. The absence of validated diagnostic kits for Alphaviruses makes even routine surveillance less feasible. For that purpose, this review describes the occurrence, genetic diversity, clinical characteristics, and the mechanisms involving Alphaviruses causing arthritis in humans. This information may serve as a basis for better awareness and detection of Alphavirus-caused diseases during outbreaks and in establishing appropriate prevention and control measures.
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| 7. |
- Lwande, Olivia Wesula, 1986-, et al.
(author)
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Globe-Trotting Aedes aegypti and Aedes albopictus : Risk Factors for Arbovirus Pandemics
- 2020
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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 20:2, s. 71-81
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Journal article (peer-reviewed)abstract
- Introduction: Two species of Aedes (Ae.) mosquitoes (Ae. aegypti and Ae. albopictus) are primary vectors for emerging arboviruses that are a significant threat to public health and economic burden worldwide. Distribution of these vectors and the associated arboviruses, such as dengue virus, chikungunya virus, yellow fever virus, and Zika virus, was for a long time restricted by geographical, ecological, and biological factors. Presently, arbovirus emergence and dispersion are more rapid and geographically widespread, largely due to expansion of the range for these two mosquitoes that have exploited the global transportation network, land perturbation, and failure to contain the mosquito population coupled with enhanced vector competence. Ae. aegypti and Ae. albopictus may also sustain transmission between humans without having to depend on their natural reservoir forest cycles due to arthropod adaptation to urbanization. Currently, there is no single strategy that is adequate to control these vectors, especially when managing arbovirus outbreaks. Objective: This review aimed at presenting the characteristics and abilities of Ae. aegypti and Ae. albopictus, which can drive a global public health risk, and suggests strategies for prevention and control. Methods: This review presents the geographic range, reproduction and ecology, vector competence, genetic evolution, and biological and chemical control of these two mosquito species and how they have changed and developed over time combined with factors that may drive pandemics and mitigation measures. Conclusion: We suggest that more efforts should be geared toward the development of a concerted multidisciplinary approach.
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| 8. |
- Lwande, Olivia Wesula, et al.
(author)
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Spatio-temporal variation in prevalence of Rift Valley fever : a post-epidemic serum survey in cattle and wildlife in Kenya
- 2015
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In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 5
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Journal article (peer-reviewed)abstract
- BACKGROUND: Rift Valley fever (RVF) is a fatal arthropod-borne zoonotic disease of livestock and humans. Since the identification of RVF in Kenya in the 1930s, repeated epizootics and epidemics coinciding with El Niño events have occurred in several locations in Africa and Saudi Arabia, causing mass deaths of livestock and humans. RVF is of great interest worldwide because of its negative effect on international livestock trade and its potential to spread globally. The latter is due to the increasing incidence of extreme climatic phenomena caused by global warming, as well as to the increase in global trade and international travel. How RVF is maintained and sustained between epidemics and epizootics is not clearly understood, but it has been speculated that wildlife reservoirs and trans-ovarian transmission in the vector may be important. Several studies have examined the role of wildlife and livestock in isolation or in a limited geographical location within the one country over a short time (usually less than a year). In this study, we examined the seroprevalence of anti-RVF antibodies in cattle and several wildlife species from several locations in Kenya over an inter-epidemic period spanning up to 7 years.METHODS: A serological survey of immunoglobulin G (IgG) antibodies to RVF using competitive ELISA was undertaken on 297 serum samples from different wildlife species at various locations in Kenya. The samples were collected between 2008 and 2015. Serum was also collected in 2014 from 177 cattle from Ol Pejeta Conservancy; 113 of the cattle were in close contact with wildlife and the other 64 were kept separate from buffalo and large game by an electric fence.RESULTS: The seroprevalence of RVF virus (RVFV) antibody was 11.6% in wildlife species during the study period. Cattle that could come in contact with wildlife and large game were all negative for RVFV. The seroprevalence was relatively high in elephants, rhinoceros, and buffalo, but there were no antibodies in zebras, baboons, vervet monkeys, or wildebeest.CONCLUSIONS: Diverse species in conservation areas are exposed to RVFV. RVFV exposure in buffalo may indicate distribution of the virus over wide geographical areas beyond known RVFV foci in Kenya. This finding calls for thorough studies on the epizootology of RVFV in specific wildlife species and locations.
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| 9. |
- Näslund, Jonas, 1979-, et al.
(author)
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Detection of Puumala and Rift Valley Fever virus by quantitative RT-PCR and virus viability tests in samples of blood dried and stored on filter paper
- 2011
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In: Journal of Virological Methods. - Amsterdam : Elsevier. - 0166-0934 .- 1879-0984. ; 178:1-2, s. 186-90
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Journal article (peer-reviewed)abstract
- Haemorrhagic fever viruses cause emerging infections worldwide, and blood or serum is the main sample used for diagnosis. However, storage and transportation of such samples from remote areas to regional laboratories may be complicated and expensive. In this study, a novel approach was evaluated for the detection of Puumala hantavirus (PUUV) RNA and Rift Valley fever virus (RVFV) RNA. Whole-blood samples spiked with viable virus particles were tested in parallel with clinical samples from patients with acute haemorrhagic fever with renal syndrome (nephropathia epidemica). Individual blood samples were spotted on filter paper, dried, and used for RNA extraction at later time points. PUUV RNA was detected by RT-PCR after storage at room temperature for up to six weeks. In contrast, only low copy numbers of RVFV RNA were detected after 1-2 days even though viable RVFV was eluted from the dried filter papers after the same time. The use of filter paper to collect and store blood samples for PUUV RNA detection is therefore a simple and reliable procedure. This approach might facilitate sampling and analysis of other RNA viruses from human or animal sources and could be used for field studies in remote areas or in developing countries.
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| 10. |
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| 11. |
- Rasmuson, Johan, 1977-, et al.
(author)
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Time to revise the paradigm of hantavirus syndromes? Hantavirus pulmonary syndrome caused by European hantavirus
- 2011
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In: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer Science and Business Media LLC. - 0934-9723 .- 1435-4373. ; 30:5, s. 685-690
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Journal article (peer-reviewed)abstract
- Hantaviruses have previously been recognised to cause two separate syndromes: hemorrhagic fever with renal syndrome in Eurasia, and hantavirus pulmonary syndrome (HPS) in the Americas. However, increasing evidence suggests that this dichotomy is no longer fruitful when recognising human hantavirus disease and understanding the pathogenesis. Herein are presented three cases of severe European Puumala hantavirus infection that meet the HPS case definition. The clinical and pathological findings were similar to those found in American hantavirus patients. Consequently, hantavirus infection should be considered as a cause of acute respiratory distress in all endemic areas worldwide.
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| 12. |
- Tigoi, Caroline, et al.
(author)
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High risk for human exposure to Rift Valley fever virus in communities living along livestock movement routes : A cross-sectional survey in Kenya
- 2020
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In: PLoS Neglected Tropical Diseases. - San Francisco : Public Library of Science. - 1935-2727 .- 1935-2735. ; 14:2
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Journal article (peer-reviewed)abstract
- Introduction: Multiple outbreaks of Rift Valley Fever (RVF) with devastating effects have occurred in East Africa. These outbreaks cause disease in both livestock and humans and affect poor households most severely. Communities living in areas practicing nomadic livestock movement may be at higher risk of infection. This study sought to i) determine the human exposure to Rift Valley fever virus (RVFV) in populations living within nomadic animal movement routes in Kenya; and ii) identify risk factors for RVFV infection in these communities.Methods: A cross-sectional descriptive study design was used. Samples were collected from the year 2014 to 2015 in a community-based sampling exercise involving healthy individuals aged ≥18 years from Isiolo, Tana River, and Garissa counties. In total, 1210 samples were screened by ELISA for the presence of immunoglobulin IgM and IgG antibodies against RVFV. Positive results were confirmed by plaque reduction neutralization test.Results: Overall, IgM and IgG prevalence for all sites combined was 1.4% (95% CI 0.8–2.3%) and 36.4% (95% CI 33.8–39.2%), respectively. Isiolo County recorded a non-significant higher IgG prevalence of 38.8% than Garissa 35.9% and Tana River 32.2% (Chi square = 2.5, df = 2, p = 0.287). Males were significantly at higher risk of infection by RVFV than females (OR = 1.67, 95% CI 1.17–2.39, p<0.005). Age was significantly associated with RVFV infection (Wald Chi = 94.2, df = 5, p<0.0001). Individuals who had regular contact with cattle (OR = 1.38, 95%CI 1.01–1.89) and donkeys (OR = 1.38, 95%CI 1.14–1.67), or contact with animals through birthing (OR = 1.69, 95%CI 1.14–2.51) were significantly at a greater risk of RVFV infection than those who did not.Conclusion: This study demonstrated that although the Isiolo County has been classified as being at medium risk for RVF, virus infection appeared to be as prevalent in humans as in Tana River and Garissa, which have been classified as being at high risk. Populations in these counties live within nomadic livestock movement routes and therefore at risk of being exposed to the RVFV. Interventions to control RVFV infections therefore, should target communities living along livestock movement pathways.
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| 13. |
- Wesula Lwande, Olivia, 1986-, et al.
(author)
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Inkoo virus : a common but unrecognized mosquito-borne virus in northern Europe
- 2017
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In: Infectious Diseases Hub.
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Research review (other academic/artistic)abstract
- Inkoo virus (INKV) is a common but less explored mosquito-borne virus belonging to family Bunyaviridae, genus Orthobunyavirus of the California serogroup. The virus was originally isolated in Finland in 1964 and has since then been detected in other northern European countries including Norway, Russia and Sweden. The virus has been associated with fever and encephalitis, in addition, patients considered positive for INKV antibodies have been linked with neurologic disease.
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| 14. |
- Yong-Dae, Kwon, 1984-, et al.
(author)
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N-glycosylation in the Pre-Membrane Protein Is Essential for the Zika Virus Life Cycle
- 2020
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In: Viruses. - : MDPI. - 1999-4915. ; 12:9
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Journal article (peer-reviewed)abstract
- Asparagine (N)-linked protein glycosylation plays an important role in protein synthesis and modification. Two Zika virus (ZIKV) structural proteins, the pre-membrane (prM) and envelope (E) protein areN-glycosylated. The prM protein of all ZIKV strains contains a singleN-linked glycosylation site, while not all strains contain an N-linked site in the E protein. Our aim was to examine the impact of prM and E N-linked glycosylation on ZIKV infectivity and cell trafficking. Using a ZIKV infectious clone, we found that when theN-glycan sites were removed, the prM- and the prM/E-double mutants did not produce an infectious virus in the supernatant. Further, by using ZIKV prME constructs, we found thatN-glycosylation was necessary for effective secretion of ZIKV virions. The absence of theN-glycan on prM or E caused protein aggregation in the rough endoplasmatic reticulum (ER) compartment. The aggregation was more pronounced for the prM-mutation, and the mutant virus lost the ER-Golgi intermediate compartment (ERGIC) localization. In addition, lack of theN-glycan on prM induced nuclear translocation of CCAAT-enhancer-binding protein homologous protein (CHOP), an ER stress marker. To conclude, we show that the prMN-glycan is essential for the ZIKV infectious cycle, and plays an important role in viral protein trafficking, protein folding, and virion assembly.
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