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| 2. |
- Bergqvist, Joakim, et al.
(author)
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Detection and Isolation of Sindbis Virus from Mosquitoes Captured During an Outbreak in Sweden, 2013
- 2015
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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:2, s. 133-140
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Journal article (peer-reviewed)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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| 3. |
- Elfving, Karin, et al.
(author)
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Serologic and Molecular Prevalence of Rickettsia helvetica and Anaplasma phagocytophilum in Wild Cervids and Domestic Mammals in the Central Parts of Sweden
- 2015
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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:9, s. 529-534
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Journal article (peer-reviewed)abstract
- Both Rickettsia helvetica and Anaplasma phagocytophilum are common in Ixodes ricinus ticks in Sweden. Knowledge is limited regarding different animal species' competence to act as reservoirs for these organism. For this reason, blood samples were collected from wild cervids (roe deer, moose) and domestic mammals (horse, cat, dog) in central Sweden, and sera were tested using immunofluorescence assay to detect antibodies against spotted fever rickettsiae using Rickettsia helvetica as antigen. Sera with a titer >= 1:64 were considered as positive, and 23.1% (104/450) of the animals scored positive. The prevalence of seropositivity was 21.5% (23/107) in roe deer, 23.3% (21/90) in moose, 36.5% (23/63) in horses, 22.1% (19/90) in cats, and 17.0% (17/100) in dogs. PCR analysis of 113 spleen samples from moose and sheep from the corresponding areas were all negative for rickettsial DNA. In roe deer, 85% (91/107) also tested seropositive for A. phagocytophilum with a titer cutoff of 1:128. The findings indicate that the surveyed animal species are commonly exposed to rickettsiae and roe deer also to A. phagocytophilum.
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| 4. |
- Goeijenbier, Marco, et al.
(author)
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Emerging Viruses in the Republic of Suriname : Retrospective and Prospective Study into Chikungunya Circulation and Suspicion of Human Hantavirus Infections, 2008-2012 and 2014
- 2015
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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:10, s. 611-618
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Journal article (peer-reviewed)abstract
- Introduction: Suriname is a country on the northeastern Atlantic coast of South America. It is unique in the sense that different ethnic cultures live together within the country, resulting in high levels of transport of both humans and products between the Asian, African, and European continents as well as the Caribbean. Travel is only one of the many factors present in Suriname contributing to the risk for the emergence or introduction of any infectious disease. Recently, circulation of both chikungunya virus (CHIKV) and hantavirus was reported in areas neighboring Suriname. Here we report a retrospective and prospective study into chikungunya and hantavirus circulation. Methods: A chikungunya and hantavirus retrospective serological study was conducted on samples submitted for dengue, leptospirosis, and/or influenza virus diagnostics between 2008 and 2012 to the Bureau of Public Health in Suriname. This was followed by a prospective CHIKV serological and molecular surveillance study until the detection of the first autochthonous CHIKV cases in Suriname in May and June of 2014. Results: None of the tested samples showed the presence of CHIKV antibodies in the retrospective serological study. Prospective testing of CHIKV-suspected patients resulted in the detection of the first autochthonous CHIKV cases in Suriname in May, 2015. In one sample, we were able to isolate and sequence the virus. Retrospective testing for the presence of hantavirus antibodies showed a relative high response in both pan-hantavirus enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). However, neutralization tests did not yield any evidence for infection with either Seoul or Andes hantavirus. Conclusion: Here we report the presence of CHIKV in the republic of Suriname and the first serological indication of hantavirus infections in symptomatic patients.
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| 5. |
- Lwande, Olivia Wesula, et al.
(author)
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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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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert. - 1530-3667 .- 1557-7759. ; 19:2, s. 128-133
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Journal article (peer-reviewed)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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| 6. |
- Malmsten, Jonas, et al.
(author)
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Vector-Borne Zoonotic Pathogens in Eurasian Moose (Alces alces alces)
- 2019
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In: Vector-Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 19, s. 207-211
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Journal article (peer-reviewed)abstract
- Climate change, with warmer temperatures and altered precipitation patterns, has affected the distribution of vectors and vector-borne diseases. In the northern hemisphere, vectors are spreading north, and with them, pathogens of zoonotic and animal health impact. Eurasian moose (Alces alces alces) are physiologically and anatomically adapted for cold climate, and are rarely considered ideal hosts of vectors, apart from deer keds (Lipoptena cervi). To investigate the presence of vector-borne pathogens, spleen samples from 615 moose were collected in southern Sweden from 2008 to 2015. The samples were analyzed with a high-throughput PCR method for 24 bacterial, and 12 parasitic pathogens. Anaplasma (82%), Borrelia (3%), Babesia (3%), and Bartonella (1%) DNA was found, showing that moose are exposed to, and can act as hosts of some of these pathogens, which can have an impact of both animal and human health. These results show that Swedish moose are exposed to pathogens that in some instances are more commonly found in regions with warmer climate, and highlights the importance of also considering moose as sentinels of vector-borne pathogens. Further research is needed to understand the effect of these pathogens on the health of individual moose and to elucidate whether climate change and moose population density interact to create the pattern observed.
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| 8. |
- Seruyange, Eric, et al.
(author)
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Seroreactivity to Chikungunya and West Nile Viruses in Rwandan Blood Donors
- 2019
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In: Vector-Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 19:10, s. 731-740
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Journal article (peer-reviewed)abstract
- Introduction: Chikungunya virus (CHIKV) and West Nile virus (WNV) have previously been reported from several African countries, including those bordering Rwanda where they may have originated. However, there have been no serosurveillance reports from Rwanda regarding these two viral pathogens. In this article, we present the first study of immunoglobulin G (IgG) seroreactivity of CHIKV and WNV in Rwandan blood donor samples. Methods: Blood donors from Rwanda (n = 874) and Sweden (n = 199) were tested for IgG reactivity against CHIKV, using an in-house enzyme-linked immunosorbent assay with the E1 envelope protein fused with p62 as antigen, and against WNV using a commercial kit. Data on mosquito distribution were obtained from the 2012 assessment of yellow fever virus circulation in Rwanda. Results: Seroreactivity to CHIKV was high in Rwanda (63.0%), when compared with Swedish donors, where only 8.5% were IgG positive. However, a cross-reactivity to O'nyong'nyong virus in neutralization test was noted in Rwandan donors. No significant difference in WNV seroreactivity was found (10.4% for Rwandan and 14.1% for Swedish donors). The relatively high seroreactivity to WNV among Swedish donors could partly be explained by cross-reactivity with tick-borne encephalitis virus prevalent in Sweden. Donors from the Eastern Province of Rwanda had the highest IgG reactivity to the two investigated viruses (86.7% for CHIKV and 33.3% for WNV). Five genera of mosquitoes were found in Rwanda where Culex was the most common (82.5%). The vector of CHIKV, Aedes, accounted for 9.6% of mosquitoes and this species was most commonly found in the Eastern Province. Conclusions: Our results showed high seroreactivity to CHIKV in Rwandan donors. The highest IgG reactivity to CHIKV, and to WNV, was found in the Eastern Province, the area reporting the highest number of mosquito vectors for these two viruses. Infection control by eliminating mosquito-breeding sites in population-dense areas is recommended, especially in eastern Rwanda.
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| 9. |
- Strand, Tanja M., 1978-, et al.
(author)
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Detection of Leptospira in Urban Swedish Rats : Pest Control Interventions as a Promising Source of Rats Used for Surveillance
- 2019
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In: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 19:6, s. 414-420
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Journal article (peer-reviewed)abstract
- Rat carcasses obtained from pest control interventions can potentially be used for an efficient surveillance of zoonotic diseases such as leptospirosis. To evaluate the performance of different laboratory methods for detection of pathogenic Leptospira spp., heart and kidney samples from wild Norway rats were analyzed by microscopic agglutination test (MAT, the gold standard), a commercial IgG enzyme-linked immunosorbent assay, and by an optimized quantitative PCR (secY qPCR, followed by sequencing). We found secY qPCR to be as sensitive as MAT for screening of Leptospira infection in pest control rats and selected secY qPCR for a larger screening of rats from urban and rural areas in central and southern Sweden. We identified secY qPCR positive rats from the cities Stockholm, Gothenburg, and Malmö, which were further confirmed by sequencing.
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| 10. |
- Strand, Tanja M, et al.
(author)
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Highly Pathogenic Leptospira Found in Urban Brown Rats (Rattus norvegicus) in the Largest Cities of Sweden
- 2015
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In: Vector-Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:12, s. 779-781
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Journal article (peer-reviewed)abstract
- Leptospirosis is an emerging zoonosis of global concern; however, its contemporary occurrence in Sweden, a European country partly located north of the Arctic Circle, is poorly known. Four out of 30 brown rats, captured within urban districts in Sweden, were found to be positive for antibodies to Leptospira interrogans serovar Icterohaemorrhagiae. This serovar causes Weil's disease in humans, a severe infection with jaundice, renal failure, and hemorrhage. Our study is the first finding of this highly pathogenic serovar in Swedish rats since the 1930s.
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