Rift Valley Fever (RVF) - update of epidemiological data and risk assessment of its penetration into Europe and Bulgaria

From 2006 to the present (2021), Rift Valley Fever among ruminants (RVF) has been recorded in South Africa, East Africa and Saudi Arabia. Outbreaks were then reported in West Africa in 2010 – 2012 with even human cases (Mauritania). Most recently, RVF was registered in Kenya, Uganda, Sudan and Tanzania, and in 2018 - 2019 a widespread epidemic was reported in Mayotte (France). The movement of live animals is the most important route for the spread of RVF from African endemic areas to North Africa and the Middle East. The emergence of major epidemics of RVF has historically been associated with climatic conditions such as floods and the appearance of mosquitoes infecting sensitive ruminants. This explains its cyclicality (over several years) in some parts of sub-Saharan Africa, such as Kenya or Mauritania. However, over the last decade, RVF epidemics have occurred more frequently in West Africa and other sub-Saharan Africa and are associated with a certain low level of circulation of the RVF virus in animals in a drier climate. Recently published studies from the Mediterranean countries show the presence of a certain level of seroprevalence in animals and humans for RVF. These countries and regions are: Turkey (2017), Tunisia (2016), Iran (2017), Iraq (2013), Algeria (2014) and Western Sahara (2011 and 2014).

Although the European Union (EU) is not exposed to imminent risk of RVF, the risks of further spread of the virus (RVFV) to the EU's neighboring Mediterranean countries (North Africa) and the Middle East do exist. The presence of competent vectors for RVFV in some Mediterranean and Western European countries, as well as the assessment of the risks of possible penetration of mosquitoes infected with this virus (from countries with endemic circulation of the virus) through active trade and transport links requires increasing our attention to the epidemic situation and the rapid response of the competent veterinary authorities of the EU member states. Close cooperation with the countries of North Africa and the Middle East is also required in cases of disease surveillance needs.

Following the identification and categorization of the specific risk factors and the proposed changes in the RVF disease control measures, according to Regulation (EU) 2016/429[1] of the European Parliament and of the Council, the Risk Assessment Center on Food Chain set a goal: to update the data on the global spread of RVF, to outline the specifics of the epidemiology and assess the risk of its penetration for Europe and Bulgaria.