Serosurvey of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) in Cattle in Livestock Areas of Côte d'Ivoire, West Africa

Background: Crimean-Congo haemorrhagic fever virus (CCHFV) is an arbovirus transmitted by Ixodid ticks and causes a highly pathogenic disease called Crimean-Congo haemorrhagic fever with a mortality rate of up to 50% in humans.

Methods: From January to December 2019, tick and blood samples were taken from seven cattle farms located in the towns of Korhogo, Bondoukou, Man and Bouaflé. In each of the farms, samples were taken from twenty cattle. These tick and blood samples were sent to the national reference laboratory of the Department of Epidemic Viruses of the Pasteur Institute of Côte d'Ivoire for diagnosis of CCHFV as part of the surveillance of haemorrhagic fever viruses in Côte d'Ivoire. Molecular detection of the Crimean-Congo haemorrhagic fevervirus in ticks was performed by real-time PCR. For the serological analysis, the ELISA was used for the detection of antibodies to CCHFV (IgM and IgG).

Results: The study allowed the identification of 411 ticks divided into three genera Amblyomma, Hyalomma and Rhipicephalus. The predominant species were Rhipicephalus (Boophilus) microplus with (47.4%) and Amblyomma variegatum with (42.8%). No ticks gave positive results for the research of the CCHFV.Serological analysis showed that all 140 blood samples were IgM negative and 53.57% were IgG positive. Cattle from Bouaflé (90%) and Korhogo (70%) showed a higher seroprevalence than cattle from other regions. There was no significant difference in seropositivity between female bovines (54.1%) and male bovines (52.5%) (P>0.05). There is an association between age and anti-CCHF IgG positivity (P≤0.05), as cattle less than 3 years old (59.3%) showed a higher seroprevalence.

Conclusion: CCHFV serological tests have been detected in cattle, one of the livestock known to play a role in the amplification of CCHFV. Our results demonstrate that the prevalence of CCHFV is high in livestock areas of Côte d'Ivoire and suggest that surveillance for CCHFV should be established.