Molecular identification and evaluation of Coxiella-like endosymbionts genetic diversity carried by cattle ticks in Algeria.

Coxiella-like bacteria are a large group of yet-to-isolate and characterize bacteria phylogenetically close to the agent of Q fever, Coxiella burnetii, and often associated with ixodid ticks worldwide. This study was designed to assess the presence of Coxiella-like endosymbionts (CLE) in ticks and to describe their genetic diversity in different tick species infesting cattle in Algeria. A total of 765 ticks were collected from three locations. The screening of 20 % of sampled ticks (147/765) exhibited the presence of Coxiella-like in 51.7 % (76/147). The sequencing of partial 16S rRNA and the GroEl genes showed an identity higher than 98 % with different Coxiella-like endosymbionts. The phylogenetic analysis based on the 16S rRNA gene showed the positions of identified Coxiella bacteria. Eleven of the 13 sequences from Rhipicephalus, Dermacentor and Hyalomma ticks were grouped in a distinct clade, the other two each represent an independent clade. This study reported that CLE are prevalent in cattle ticks. Most of the identified Coxiella-like bacteria, from different species of ticks found on cattle, were identical. This may mean that, unlike the currently accepted paradigm, Coxiella-like bacteria are not only tick host-associated, but rather can be transmitted from one tick species to another via the vertebrate host.