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Biological Health Hazard – Invasive Migrant Viruses Sindbis and Inkoo: Sweden


Migration Health Hazard – Vector Borne Zoonotic Diseases

Published Date: 2016-05-14 19:28:26
Subject: PRO> Sindbis and Inkoo viruses – Sweden
Archive Number: 20160514.4222336

Date: Mon 9 May 2016
Source: Vector Borne Zoonotic Diseases pub ahead of print [edited]

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.

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 1st and 2nd 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 3 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.

Communicated by:
ProMED-mail from HealthMap Alerts

[Finding evidence of transovarial transmission of Inkoo virus, an orthobunyavirus, is not surprising, since many of the viruses in this genus are maintained in nature through this mechanism. Finding a significant proportion of Sindbis virus, an Alphavirus, in larvae is of considerable interest. One hopes that these field observations will be followed up by laboratory experiments to determine filial infection rates and transmission efficiency for both viruses.

Sindbis virus is a very widely distributed Alphavirus, occurring in Africa, Eurasia, Oceania and Australia. It has caused outbreaks of human disease in South Africa and in northern Europe. Sindbis virus infection in humans causes fever, malaise, rash and musculoskeletal pain. In a significant portion of patients the debilitating musculoskeletal symptoms may persist for years, with many features with autoimmune diseases.

Inkoo virus (INKV) is a member of the California serogroup orthobunyaviruses. They have a high seroprevalence among humans in northern Europe. INKV infections are usually subclinical, but may cause more severe disease in children where symptoms may include fever, influenza-like illness, nausea or vomiting, disorientation, nuchal rigidity, headache, drowsiness, and seizures.

Adouchief S, Smura T, Sane J, Vapalahti O, Kurkela S. Sindbis virus as a human pathogen-epidemiology, clinical picture and pathogenesis. Rev Med Virol. 2016 Mar 15. doi: 10.1002/rmv.1876. [Epub ahead of print] Review. PMID: 26990827.

Putkuri N, Kantele A, Levanov L, Kivistö I, Brummer-Korvenkontio M, Vaheri A, Vapalahti O. Acute Human Inkoo and Chatanga Virus Infections, Finland. Emerg Infect Dis. 2016 May;22(5):810-7. doi: 10.3201/eid2205.151015.

A HealthMap/ProMED-mail map of Sweden can be accessed at – Mod.TY]

See Also

Sindbis virus – Germany: mosquitoes 20100504.1446
Sindbis virus – Finland (02): background 20100115.0179
Sindbis virus – Finland 20100114.0173

Sindbis virus – Finland (2) 19950922.0870
Sindbis virus – Finland 19950921.0859

A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases

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