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Tingström O, Wesula Lwande O, Näslund J, Spyckerelle I, Engdahl C, Von Schoenberg P, Ahlm C, Evander M, Bucht G. Detection of Sindbis and Inkoo Virus RNA in Genetically Typed Mosquito Larvae Sampled in Northern Sweden. Vector Borne Zoonotic Dis 2016; 16:461-7. [PMID: 27159120 PMCID: PMC4931352 DOI: 10.1089/vbz.2016.1940] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Introduction: Mosquito-borne viruses have a widespread distribution across the globe and are known to pose serious threats to human and animal health. The maintenance and dissemination of these viruses in nature are driven through horizontal and vertical transmission. In the temperate climate of northern Sweden, there is a dearth of knowledge on whether mosquito-borne viruses that occur are transmitted transovarially. To gain a better understanding of mosquito-borne virus circulation and maintenance, mosquito larvae were sampled in northern Sweden during the first and second year after a large outbreak of Ockelbo disease in 2013 caused by Sindbis virus (SINV). Materials and Methods: A total of 3123 larvae were sampled during the summers of 2014 and 2015 at multiple sites in northern Sweden. The larvae were homogenized and screened for viruses using RT-PCR and sequencing. Species identification of selected larvae was performed by genetic barcoding targeting the cytochrome C oxidase subunit I gene. Results and Discussion: SINV RNA was detected in mosquito larvae of three different species, Ochlerotatus (Oc.) communis, Oc. punctor, and Oc. diantaeus. Inkoo virus (INKV) RNA was detected in Oc. communis larvae. This finding suggested that these mosquitoes could support transovarial transmission of SINV and INKV. Detection of virus in mosquito larva may serve as an early warning for emerging arboviral diseases and add information to epidemiological investigations before, during, and after outbreaks. Furthermore, our results demonstrated the relevance of genetic barcoding as an attractive and effective method for mosquito larva typing. However, further mosquito transmission studies are needed to ascertain the possible role of different mosquito species and developmental stages in the transmission cycle of arboviruses.
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Affiliation(s)
- Olov Tingström
- 1 Swedish Defence Research Agency , CBRN Defence and Security, Umeå, Sweden .,2 Department of Clinical Microbiology, Virology, Umeå University , Umeå, Sweden .,3 Department of Clinical Microbiology, Infectious Diseases, Umeå University , Umeå, Sweden
| | | | - Jonas Näslund
- 1 Swedish Defence Research Agency , CBRN Defence and Security, Umeå, Sweden
| | - Iris Spyckerelle
- 2 Department of Clinical Microbiology, Virology, Umeå University , Umeå, Sweden .,3 Department of Clinical Microbiology, Infectious Diseases, Umeå University , Umeå, Sweden
| | - Cecilia Engdahl
- 1 Swedish Defence Research Agency , CBRN Defence and Security, Umeå, Sweden
| | | | - Clas Ahlm
- 3 Department of Clinical Microbiology, Infectious Diseases, Umeå University , Umeå, Sweden
| | - Magnus Evander
- 2 Department of Clinical Microbiology, Virology, Umeå University , Umeå, Sweden
| | - Göran Bucht
- 1 Swedish Defence Research Agency , CBRN Defence and Security, Umeå, Sweden
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Evander M, Putkuri N, Eliasson M, Lwande OW, Vapalahti O, Ahlm C. Seroprevalence and Risk Factors of Inkoo Virus in Northern Sweden. Am J Trop Med Hyg 2016; 94:1103-1106. [PMID: 26928830 PMCID: PMC4856611 DOI: 10.4269/ajtmh.15-0270] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 12/31/2015] [Indexed: 11/10/2022] Open
Abstract
The mosquito-borne Inkoo virus (INKV) is a member of the California serogroup in the family Bunyaviridae, genus Orthobunyavirus. These viruses are associated with fever and encephalitis, although INKV infections are not usually reported and the incidence is largely unknown. The aim of the study was to determine the prevalence of anti-INKV antibodies and associated risk factors in humans living in northern Sweden. Seroprevalence was investigated using the World Health Organization Monitoring of Trends and Determinants in Cardiovascular Disease study, where a randomly selected population aged between 25 and 74 years (N = 1,607) was invited to participate. The presence of anti-INKV IgG antibodies was determined by immunofluorescence assay. Seropositivity for anti-INKV was significantly higher in men (46.9%) than in women (34.8%; P < 0.001). In women, but not in men, the prevalence increased somewhat with age (P = 0.06). The peak in seropositivity was 45–54 years for men and 55–64 years for women. Living in rural areas was associated with a higher seroprevalence. In conclusion, the prevalence of anti-INKV antibodies was high in northern Sweden and was associated with male sex, older age, and rural living. The age distribution indicates exposure to INKV at a relatively early age. These findings will be important for future epidemiological and clinical investigations of this relatively unknown mosquito-borne virus.
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Affiliation(s)
| | | | | | | | | | - Clas Ahlm
- *Address correspondence to Clas Ahlm, Department of Clinical Microbiology, Infectious Diseases, Umeå University, SE-901 85 Umeå, Sweden. E-mail:
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Medlock JM, Snow KR, Leach S. Possible ecology and epidemiology of medically important mosquito-borne arboviruses in Great Britain. Epidemiol Infect 2006; 135:466-82. [PMID: 16893487 PMCID: PMC2870593 DOI: 10.1017/s0950268806007047] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2006] [Indexed: 11/07/2022] Open
Abstract
Nine different arboviruses are known to be transmitted by, or associated with, mosquitoes in Europe, and several (West Nile, Sindbis and Tahyna viruses) are reported to cause outbreaks of human disease. Although there have been no reported human cases in Great Britain (GB), there have been no published in-depth serological surveys for evidence of human infection. This paper investigates the ecological and entomological factors that could influence or restrict transmission of these viruses in GB, suggesting that in addition to West Nile virus, Sindbis and Tahyna viruses could exist in enzootic cycles, and that certain ecological factors could facilitate transmission to humans. However, the level of transmission is likely to be lower than in endemic foci elsewhere in Europe due to key ecological differences related to spatial and temporal dynamics of putative mosquito vectors and presence of key reservoir hosts. Knowledge of the potential GB-specific disease ecology can aid assessments of risk from mosquito-borne arboviruses.
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Affiliation(s)
- J M Medlock
- Health Protection Agency, Centre for Emergency Preparedness & Response, Porton Down, Salisbury, Wiltshire, UK.
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