Avian zoonotic arboviruses: Transmission dynamics, epidemiology, and control strategies.

The genus Flavivirus includes over 70 arthropod-borne viruses. West Nile Virus (WNV) and Usutu Virus (USUV) primarily affect birds but can also cause serious diseases in humans and horses (dead-end hosts). WNV was first identified in Uganda in 1937 and has spread to Europe and North America. USUV emerged in Africa in 1959 and later caused outbreaks in European blackbirds and owls. Both viruses are transmitted mainly by Culex spp. (vector), in which birds serve as their primary reservoirs. Climatic changes influence the transmission dynamics of these viruses by affecting mosquito dynamics. The WNV causes severe neurological disease in birds, while USUV typically leads to milder infections but may cause serious pathological conditions in some birds. In humans, WNV infections range from asymptomatic to neuroinvasive, whereas USUV infections are mostly mild, with occasional cases of encephalitis. Indeed, the control strategies involve vector management practices and surveillance. While vaccines exist for WNV in horses, none are currently licensed for birds. Experimentally, WNV vaccines show promising effects in birds, emphasizing the need for targeted development. This review highlights the transmission dynamics, epidemiology, and control strategies of WNV and USUV, with a particular focus on the situation in Germany. A thorough understanding of the transmission, epidemiology, and control of these viruses is essential for mitigating their impact on wildlife and public health. Climate-driven changes in mosquito populations underscore the need for ongoing surveillance and collaboration. The absence of licensed vaccines for birds and humans warranted the need for further research. Strengthening monitoring and targeted interventions could help reduce the risk of outbreaks and protect biodiversity and human health. [ABSTRACT FROM AUTHOR]