Patterns of Emergence and Circulation of West Nile Virus in Algeria

In recent years, many countries have experienced increased outbreaks of emerging infectious diseases, such as West Nile virus (WNV). WNV is transmitted to humans by Culex mosquitoes and has an enzoonotic transmission cycle involving birds. In Algeria, serological evidence of WNV in humans dates back to the 1970s, but circulation patterns are poorly characterized. To address this, we conducted a cross-sectional seroprevalence survey of WNV in humans and fitted serocatalytic models to the data. We also analyzed data on severe WNV cases. In this study, we report a seroprevalence of 16.7%. We identify age, region, and residence type as risk factors for the infection. We also show that patterns of spread in two provinces in the south are consistent with low level endemic risk over decades, while those from three provinces in the north are all consistent with a single, recent outbreak.