Spatio-temporal variations and genetic diversity of Anaplasma spp. in cattle from the North of Tunisia

In cattle, anaplasmosis is a tick-borne rickettsial disease caused by Anaplasma marginale, A. centrale, A. phagocytophilum, and A. bovis. To date, no information concerning the seasonal dynamics of single and/or mixed infections by different Anaplasma species in bovines are available in Tunisia. In this work, a total of 1035 blood bovine samples were collected in spring (n = 367), summer (n = 248), autumn (n = 244) and winter (n = 176) from five different governorates belonging to three bioclimatic zones from the North of Tunisia. Molecular survey of A. marginale, A. centrale and A. bovis in cattle showed that average prevalence rates were 4.7% (minimum 4.1% in autumn and maximum 5.6% in summer), 7% (minimum 3.9% in winter and maximum 10.7% in autumn) and 4.9% (minimum 2.7% in spring and maximum 7.3% in summer), respectively. A. phagocytophilum was not detected in all investigated cattle. Seasonal variations of Anaplasma spp. infection and co-infection rates in overall and/or according to each bioclimatic area were recorded. Molecular characterization of A. marginale msp4 gene indicated a high sequence homology of revealed strains with A. marginale sequences from African countries. Alignment of 16S rRNA A. centrale sequences showed that Tunisian strains were identical to the vaccine strain from several sub-Saharan African and European countries. The comparison of the 16S rRNA sequences of A. bovis variants showed a perfect homology between Tunisian variants isolated from cattle, goats and sheep. These present data are essential to estimate the risk of bovine anaplasmosis in order to develop integrated control policies against multi-species pathogen communities, infecting humans and different animal species, in the country.