A screening for Schmallenberg virus among sheep, goats and cattle in Zambezia province, Moçambique : and preparations for a metagenomic survey of virus in mosquitoes

Abstract: As the world´s population increases and people's living conditions are improving, larger areas are needed for houses as well as food production. This means that new areas are exploited and that people, livestock, blood sucking insects and wild animals are forced to live close together. In combination with the global warming, leading to extreme weather such as floods and storms, this allows both new and old pathogens to emerge. The number of "emerging infectious diseases", EIDs, has increased in recent years and many of them have their origin in poor, tropical countries. Moçambique is therefore considered to be a high risk area for EIDs. Schmallenberg virus, SBV, was discovered in 2011 as an "emerging infectious disease" in dairy cows in Germany. The virus causes fever, diarrhea and reduced milk production in dairy cows as well as abortions and malformations in newborn calves. From these cows could SBV be detected using metagenomic technique. When the virus was identified in cows it soon was found in other ruminants, both wild and domestic. Hence it is mainly in cattle, sheep and goat the virus has led to problems and financial losses. Phyelogenetic studies showed that Schmallenberg virus is an Orthobunyavirus from the Simbu-serogroup. The virus is transmitted by biting midges, Culicoides spp, and thru its vector it has spread to large parts of Europe. The study done in Moçambique includes two parts, a serological screening for Schmallenberg virus in cattle, goats and sheep and a metagenomic study on viruses in mosquitoes in the Zambezia province. The samples were prepared and analyzed at the lab at the University of Eduardo Mondlane (UEM), Maputo, Moçambique. The metagenomic study will be completed in Sweden at the State University of Agricultural Sciences in Uppsala. When screening for Schmallenberg virus an ELISA kit "ID screen Schmallenberg virus Competition Multi-species" was used. In the study a majority of the tested animals were positive. Most animals were also positive when the serum was diluted 1:2, 1:4 and 1:8. The largest numbers of positive animals were found among the cattle where 100% tested positive. Among the sheep the average prevalence was 63% and among the goats 84%. This is the first study on Schmallenberg virus made outside Europe. In Europe, no viruses cross-reacting with SBV are known and therefore this is not investigated. However, on the African continent, there are a large number of viruses that Schmallenberg virus potentially could cross-react with. Therefore, to confirm the positive- ELISA result further studies need to be done, isolating Schmallenberg virus.