Seroprevalence of Crimean-Congo hemorrhagic fever virus among people living with HIV in Brazzaville, Congo and among blood donors in Bamako, Mali

Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of Crimean-Congo hemorrhagic fever (CCHF), a highly contagious and potentially fatal emerging disease. We assessed CCHFV seroprevalence by conducting a serological survey of two cohorts from Brazzaville, Congo and Bamako, Mali. We retrospectively screened 581 sera samples, including 352 from monitoring centers for people living with HIV (PLWH) in Brazzaville and 229 provided by the Blood Transfusion Center at Gabriel Touré Hospital in Bamako. An ELISA kit (ID Screen® CCHF Double Antigen Multi-species, Innovative Diagnostics) was used to detect total anti-CCHFV antibodies in serum. CCHFV seroprevalence was 0.6% in the PLWH cohort in Brazzaville, all in a peri‑urban area near livestock/agriculture, and 1.75% in a cohort of blood donors in Bamako, half living in a peri‑urban area near livestock/agriculture and the others performing risk-exposure activities, such as working as a butcher or with frequent rural travels. PLWH from Brazzaville were mostly female, older, and more highly educated, with a tertiary sector activity and living in an urban biotope without livestock/agricultural activities in the surroundings, in contrast to the blood donors of Bamako, who were younger and more likely to live in peri‑urban/rural areas with livestock/agricultural activities in the surroundings. Despite a low CCHFV seroprevalence, our study indicates human contact with CCHFV in sub-urban areas of the capital cities of Congo and Mali associated with previously described CCHFV risk factors.