Tick Species Infesting Livestock in Three Bioclimatic Areas of Senegal: Bioecology, Prevalence of Tick Infestation, Associated Categorical Factors and Crimean-Congo Haemorrhagic Fever Virus Infection.

BACKGROUND

Crimean-Congo haemorrhagic fever (CCHF), a disease of medical and veterinary importance in several countries including Senegal, is transmitted by ticks or exposure to infected body fluids. Severe human cases of CCHF were recently observed across Senegal suggesting modification of the endemicity area and the tick fauna.

OBJECTIVE

This study aims to investigate some aspects associated with the bioecology of ticks infesting livestock and their infection with CCHF virus (CCHFV) across three bioclimatic areas of Senegal.

METHODS

Ticks were collected between October 2020 and November 2022, from randomly selected cattle, goats and sheep in the Sahelian, Sudano-Sahelian and Sudanian zones. They were screened for CCHFV RNA by RT-PCR.

RESULTS

A total of 3632 animals were examined, and 35.3% (95% CI: 33.8-36.9) were found tick-infested. The overall tick infestation rate was 81.7% (95% CI: 78.1-84.9) in cattle, 30.3% (95% CI: 28.2-32.5) in sheep and 24.1% (95% CI: 21.8-26.5) in goats. TIR differed per age, gender, host species and bioclimatic area. Overall, 7734 ticks belonging to 12 species and 3 genera were collected. The most abundant species included Rhipicephalus evertsi (32.7%) and Hyalomma impeltatum (20.1%). CCHFV was detected in 6 of the 1709 tested pools with an overall minimum infection rate (MIR) of 0.8‰. Infected ticks (H. impeltatum and H. rufipes) were collected mainly from the anogenital areas of sheep and cattle in the Sahelian and Sudano-Sahelian zones.

CONCLUSION

These updated data on ticks and CCHFV vectors in Senegal will be useful for the prevention and control of tick-borne diseases.