Dengue, Chikungunya and West Nile Virus in North Africa: Documented Transmission and Limits of Detection

Evidence on dengue, chikungunya and West Nile virus (WNV) in North Africa has been synthesised one virus at a time or at continental scale. This narrative review with a structured search brings all three together for Morocco, Algeria, Tunisia, Libya, Egypt and Sudan, and asks whether few reported cases reflect under-detection or low transmission. PubMed/MEDLINE, Scopus and Google Scholar were searched from 1940 to 3 October 2026, with WHO reports and citation chaining; each source was assigned one of five evidence levels and claims worded to match. WNV transmission is documented in Egypt, where the virus was isolated from human sera in 1951, and in Algeria, Tunisia, Morocco and Libya, with recurrent neuroinvasive outbreaks in Tunisia (1997–2023) and Algeria (1994). The reported excess of North African seroprevalence over Southern Europe (15.4% against 2.7%) rests largely on assays without neutralization confirmation; where both were measured, confirmed values were lower (6.7% against 9.8% in Algiers; 10% against 25% in Tunisian horses in 2023). Dengue and chikungunya transmission is documented in Sudan, including all four dengue serotypes in Kassala in 2023–24, and in Egypt, in Upper Egypt and on the Red Sea and Sinai coasts. Neither has been reported as locally acquired in the Maghreb or Libya, although Aedes albopictus has been present there for 8 to 16 years and transmits chikungunya virus in the laboratory. Reported case counts cannot distinguish low transmission from non-detection. The study most needed is a neutralization-confirmed serosurvey of these two viruses in resident Maghreb populations.