Seroprevalence of Alphaviruses (Togaviridae) among Urban Population in Nouakchott, Mauritania, West Africa

Abstract

The presence of alphaviruses, such as chikungunya virus (CHIKV), has never been reported in Mauritania. We assessed the seroprevalence of CHIKV among Nouakchott residents. A cross-sectional study involving 1300 non-febrile patients consulting at the Nouakchott hospital center was conducted between January and June 2021. The presence of anti-CHIKV IgG and neutralizing antibodies against CHIKV, O'nyong-nyong virus (ONNV), and Semliki Forest virus (SFV) was determined by an enzyme-linked immunosorbent assay (ELISA) and a serum neutralization test, respectively, and the associated risk factors were investigated. Of the 1300 study participants, serological evidence of previous exposure to CHIKV was observed in 37 individuals (2.8%). Sex, age, reported use of repellants, and bed net ownership and usage were not associated with CHIKV seropositivity. Our results showed the co-circulation of two other alphaviruses, ONNV and SFV, in Nouakchott in 30 (2.3%) individuals. This is the first study that documents the co-circulation of CHIKV, ONNV, and SFV in Mauritania, albeit at low prevalence. Surveillance and routine testing for alphaviruses and other arboviruses in symptomatic patients should be implemented in health facilities to assess the health burden associated with these viruses. Efforts should also be made to strengthen the vector control measures.

Keywords: ELISA; Mauritania; Nouakchott; O’nyong-nyong; Semliki Forest; alphavirus; arbovirus; chikungunya; neutralization; seroprevalence.

Figure 1

Map of Nouakchott, Mauritania, showing the location of the study site: the National Hospital Center located in the Tevragh Zeina district. Colored areas correspond to three Nouakchott regions: northern Nouakchott region (light green), including the districts of Dar Naim, Teyarett, and Toujounin; southern Nouakchott region (salmon pink) with the districts of Arafat, Riadh, and El Mina; and western Nouakchott region (orange) corresponding to the districts of Sebkha, Tevragh Zeina, and Ksar. The large white band in a rectangular shape in the Dar Naim district represents the former international airport (closed since 2016 due to the opening of the new international airport situated outside the city). The Atlantic Ocean lies to the west of the city. Adapted from [32]. Figure available online: http://books.openedition.org/pupo/docannexe/image/17487/img-2.jpg (accessed on 15 September 2022).