Great diversity of Piroplasmida in Equidae in Africa and Europe, including potential new species

Piroplasms are Apicomplexa tick-borne parasites distributed worldwide. They are responsible for piroplasmosis (theileriosis and babesiosis) in Vertebrata and are therefore of medical and economic importance. Herein, we developed a new real time PCR assay targeting the 5.8S rRNA gene and three standard PCR assays, targeting 18S rRNA, 28S rRNA, and coxl genes, for the detection of piroplasmids. These assays were first optimized and screened for specificity and sensitivity. Then, they were used to study a total of 548 blood samples and 97 ticks collected from Equidae in four sub-Saharan countries (Senegal, Democratic Republic of the Congo, Chad, and Djibouti) and France (Marseille and Corsica). DNA of piroplasms was detected in 162 of 548 (29.5%) blood samples and in 9 of 97 (9.3%) ticks. The highest prevalence in blood samples was observed in Chad in 2016 with 72.9% positivity rate. Sequencing allowed the identification of four species of piroplasms, including two potentials new species. Theileria equi was mainly found. The highest prevalence was observed in Senegal (14 positive out of 23, 60.87%). Babesia caballi was detected in one horse in Senegal. Two new potential Theileria species were detected: Theileria sp. Africa, observed in all areas excepted in Marseille and Theileria sp. Europa, observed in Marseille and Corsica. In conclusion, sensitive and specific PCR assays were developed for epidemiological studies of Piroplasmida. The circulation of multiple species of piroplasms, including two potentials new species, observed among Equidae from sub-Saharan Africa and France.