Detection of Rickettsia aeschlimannii and Rickettsia africae in ixodid ticks from Burkina Faso and Somali Region of Ethiopia by new real-time PCR assays.

In the framework of cooperation for development projects in Burkina Faso and Ethiopia, we collected ixodid ticks from cattle, small ruminants and camels. We optimized new TaqMan Probe real-time PCR assays to detect Rickettsia aeschlimannii and Rickettsia africae OmpA gene in the collected samples. Rickettsia africae was identified in 75.0% Amblyomma variegatum (95%CI: 56.6-88.5), while R. aeschlimannii in 24.0% Hyalomma truncatum (95%CI: 9.4-45.1) and 50.0% H. rufipes (95%CI: 29.9-70.0) collected from cattle in different provinces throughout Burkina Faso. Ticks from the Libaan zone, Somali Region of Ethiopia, were also infected by R. africae (28.5% prevalence in Amblyomma gemma, 95%CI: 14.7-46.0) and R. aeschlimannii (27.0% H. truncatum, 95%CI: 5.0-62.9; 88.3% H. rufipes, 95%CI: 60.5-99.3). All tested ticks were adults. The developed diagnostic tools were highly sensitive and enabled us to rapidly classify R. aeschlimannii and R. africae, which were identified in Burkina Faso and in the Somali Region of Ethiopia for the first time. Further studies are needed to assess the zoonotic risk and prevalence of infection in local human populations, who have high contact rates with ticks and their animal hosts.