Economic Aspects of Bovine Ephemeral Fever (BEF) Outbreaks in Dairy Cattle Herds

SIMPLE SUMMARY: Bovine ephemeral fever (BEF) is a viral disease of cattle that is transmitted by blood-feeding insects. In Israel, farmers routinely report data on every BEF case to the Farm Herd Management Program (NOA), and they are registered in the Israel Cattle Breeders Association herd book. In this study, we used the statistical capability of national data stored in the Israeli herd book to evaluate the economic effects of BEF outbreaks. Our results show substantial economic losses from the reduction in milk production and culling of valuable cows. Due to climatic change, the risk of bovine ephemeral fever virus (BEFV) emergence and spread in Europe is real. Since the European cattle population has never been exposed to BEFV, the economic losses to dairy and beef production in this continent during its first BEF outbreak may be considerable. Additionally, it could also cause financial damage due to restrictions on animal trade and transportation, like the current EHDV-8 outbreak in the Mediterranean basin. These results, exhibiting for the first time to our knowledge, the impact of BEF outbreaks at a population level could enable us to conduct an accurate risk assessment in future cases of BEFV emergence. ABSTRACT: Bovine ephemeral fever virus (BEFV) is an arthropod-borne virus (arbovirus) transmitted by blood-feeding insects (mosquitoes and Culicoides biting midges). While the dispersal of arboviral diseases such as bovine ephemeral fever (BEF) into naive areas is often the result of globalization and animal movement, the endemization and local outbreaks of these diseases are mainly influenced by environmental changes. Climate change affects the activity, distribution, dynamics, and life cycles of these vectors (arthropods), the replication of viruses within their vectors, and weakens animal’s immune systems. Although BEF does not currently occur in the Americas and Europe (other than in the western regions of Turkey), the risk of BEFV emergence, spread, and endemization in Europe is real. Over the past two decades, arboviruses such as the bluetongue virus (BTV) and Schmallenberg virus (SBV) have emerged in Europe without warning and caused significant losses to the dairy and meat industries. Since the European cattle population has never been exposed to BEFV, the economic losses to dairy and beef production in this continent due to the reduction in milk production, loss of valuable cows, and abortion, should BEF emerge, would probably be considerable. Moreover, arboviruses can also cause substantial financial damage due to restrictions on animal trade and transportation, like the current EHDV-8 outbreak in the Mediterranean basin. In this study, we used national data stored in the Israeli herd book to examine the economic aspects of BEF outbreaks in affected dairy cattle farms countrywide. Our results demonstrate that BEF outbreaks can have immediate and delayed effects, causing severe economic losses due to culling (loss of valuable cows) and a reduction in milk production that affects dairy farm income for months after clinical diagnosis. To our knowledge, this is the first extensive study on the impact of a BEF outbreak at a population level, enabling to conduct accurate risk assessments in future cases of BEFV emergence and re-emergence.