Inkoo and Sindbis viruses in blood sucking insects, and a serological study for Inkoo virus in semi-domesticated Eurasian tundra reindeer in Norway

Background Mosquito-borne viruses pose a serious threat to humans worldwide. There has been an upsurge in the number of mosquito-borne viruses in Europe, mostly belonging to the families Togaviridae, genus Alphavirus (Sindbis, Chikungunya), Flaviviridae (West Nile, Usutu, Dengue), and Peribunyaviridae, genus Orthobunyavirus, California serogroup (Inkoo, Batai, Tahyna). The principal focus of this study was Inkoo (INKV) and Sindbis (SINV) virus circulating in Norway, Sweden, Finland, and some parts of Russia. These viruses are associated with morbidity in humans. However, there is a knowledge gap regarding reservoirs and transmission. Therefore, we aimed to determine the prevalence of INKV and SINV in blood sucking insects and seroprevalence for INKV in semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway. Materials and methods In total, 213 pools containing about 25 blood sucking insects (BSI) each and 480 reindeer sera were collected in eight Norwegian reindeer summer pasture districts during 2013-2015. The pools were analysed by RT-PCR to detect INKV and by RT-real-time PCR for SINV. Reindeer sera were analysed for INKV-specific IgG by an Indirect Immunofluorescence Assay (n = 480, IIFA) and a Plaque Reduction Neutralization Test (n = 60, PRNT). Results Aedes spp. were the most dominant species among the collected BSI. Two of the pools were positive for INKV-RNA by RT-PCR and were confirmed by pyrosequencing. The overall estimated pool prevalence (EPP) of INKV in Norway was 0.04%. None of the analysed pools were positive for SINV. Overall IgG seroprevalence in reindeer was 62% positive for INKV by IIFA. Of the 60 reindeer sera- analysed by PRNT for INKV, 80% were confirmed positive, and there was no cross-reactivity with the closely related Tahyna virus (TAHV) and Snowshoe hare virus (SSHV). Conclusion The occurrence and prevalence of INKV in BSI and the high seroprevalence against the virus among semi-domesticated reindeer in Norway indicate that further studies are required for monitoring this virus. SINV was not detected in the BSI in this study, however, human cases of SINV infection are yearly reported from other regions such as Rjukan in south-central Norway. It is therefore essential to monitor both viruses in the human population. Our findings are important to raise awareness regarding the geographical distribution of these mosquito-borne viruses in Northern Europe.Peer reviewe

The Molecular Epidemiology of Enterovirus in a Birth Cohort in Nepal

Acute gastroenteritis (AGE) has a major impact on morbidity and mortality worldwide. The viral aetiology of diarrhoeal diseases may remain unknown due to limited diagnostic facilities. Non-polio enteroviruses (NPEVs) are the third most frequent pathogen detected in stool specimens from AGE cases, yet their potential role in AGE is uncertain. In Nepal, limited data are available on NPEVs, due to both the lack of an adequate surveillance program and the availability of tests. The global polio eradication initiative effort of the WHO has eradicated the incidence of poliomyelitis and acute flaccid paralysis (AFP) from many parts of the world, including Nepal. However, cases of AFP associated with NPEVs have been reported in different countries, including the neighbouring India. This study aims to investigate the diarrhoeal stool samples from a birth cohort until the age of 36 months for NPEVs and the genotype diversity of NPEV in community children with diarrhoea. A total of 280 longitudinal diarrhoeal stool samples that were negative for other enteric pathogens were tested using RT-PCRs. NPEVs was detected in 97 stool specimens (34.6%) and were significantly more frequent in infants up to one year of age. This study identified 17 various NPEV types, with the dominating species being Enterovirus B (EV-B). Ten different types of echoviruses were recorded in this study, with the two rare NPEVs B74 and A120. Based on prevalence, seasonality, and diversity, further studies are warranted to investigate the role of enterovirus in diarrhoeal disease