West Nile virus (WNV) is the aetiological agent of the mosquito-borne zoonotic disease West Nile fever. The
virus, first isolated in Uganda in 1937, evolved into two distinct lineages in sub-Saharan Africa (SSA) that
subsequently spread to most continents where the virus has evolved further as evident through phylogenetic
analysis of extant genomes. Numerous published reports from the past 70 years from countries in SSA indicate
that the virus is endemic across the region. However, due in part to the limited availability of diagnostic
methods across large areas of the continent, the human burden of WNV is poorly understood. So too are the
drivers for translocation of the virus from countries south of the Sahara Desert to North Africa and Europe.
Migratory birds are implicated in this translocation although the transient viraemia, measured in days, and the
time taken to migrate, measured in weeks, suggest a more complex mechanism is in play. This review
considers the evidence for the presence of WNV across SSA and the role of migratory birds in the emergence
of the virus in other continents.