A survey of the tick-borne disease Crimean-Congo hemorrhagic fever in southern Algeria: First serological evidence in the dromedary camel population

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral zoonosis caused by a Nairovirus, Crimean-Congo hemorrhagic fever virus (CCHFV). Despite its wide geographical distribution, the epidemiology of CCHF in northern Africa is incompletely understood and its occurrence in Algeria is virtually unknown. The present survey aimed to determine the prevalence of CCHF antibodies and to identify the potential risk factors associated with CCHFV seropositivity among the one-humped camel (Camelus dromedarius) in southern Algeria. A total of 269 camels selected randomly from slaughterhouses in three wilayas were employed in the study. Sera sampled were tested for the presence of CCHFV-specific IgG antibodies using enzyme-linked immunosorbent assay (ELISA). CCHFV seropositivity was recorded in 255 out of 269 camels accounting for a prevalence rate of 94.8% (95%CI = 92.14-97.45). The seroprevalence by origin was determined to be 97% (193/199) in imported camels and 86% (49/57) in local ones (p > 0.25). Tick presence (OR = 12.35, 95%CI = 1.41-107.43, p < 0.05) was recorded as the only potential risk factor for contracting CCHFV. This study shows for the first time that camels are exposed to CCHFV in Algeria with a significantly high seroprevalence. It also underlines the need for further research to investigate the broader extent of circulating CCHFV in the country, whether in humans, animals, or ticks.