First molecular detection and characterization of zoonotic Bartonella species in fleas infesting domestic animals in Tunisia

Bartonellosis is an emerging vector-borne disease caused by different intracellular bacteria of the genus Bartonella (Rhizobiales: Bartonellaceae) that is transmitted primarily by blood-sucking arthropods such as sandflies, ticks and fleas. In Tunisia, there are no data available identifying the vectors of Bartonella spp. In our research, we used molecular methods to detect and characterize Bartonella species circulating in fleas collected from domestic animals in several of the country's bioclimatic areas. A total of 2178 fleas were collected from 5 cats, 27 dogs, 34 sheep, and 41 goats at 22 sites located in Tunisia's five bioclimatic zones. The fleas were identified as: 1803 Ctenocephalides felis (83%) (Siphonaptera: Pulicidae), 266 C. canis (12%) and 109 Pulex irritans (5%) (Siphonaptera: Pulicidae). Using conventional PCR, we screened the fleas for the presence of Bartonella spp., targeting the citrate synthase gene (gltA). Bartonella DNA was detected in 14% (121/866) of the tested flea pools [estimated infection rate (EIR) per 2 specimens: 0.072, 95% confidence interval (CI): 0.060-0.086]. The Bartonella infection rate per pool was broken down as follows: 55% (65/118; EIR per 2 specimens: 0.329, 95% CI: 0.262-0.402) in C. canis; 23.5% (8/34; EIR per 2 specimens: 0.125, 95% CI: 0.055-0.233) in P. irritans and 6.7% (48/714; EIR per 2 specimens: 0.032, 95% CI: 0.025-0.045) in C. felis. Infection rates, which varied significantly by bioclimatic zone (P