Investigation of tick-borne pathogens by conventional and molecular techniques in cattleof North-Eastern region of India

Abstract

The present study underscores the investigation on prevalence of tick-borne pathogens of cattle both from hosts as well vectors from this part of India by conventional blood smear examination and through molecular techniques. A total of 1,153 cattle belonging to different age groups, breeds, sex were screened during the period from April, 2020 to March, 2021. Blood smear examination as well as PCR assay were followed to detect tick-borne pathogens in collected samples. The tick species recorded were Rhipicephalus (Boophilus) microplus, Hyalomma anatolicum anatolicum and Haemaphysalis leachi leachi .Overall prevalence of tick-borne pathogens was recorded as 33.30%. Mixed infection with Theileria sp. and Anaplasma sp. was found highest among infected cattle followed by single infection of Anaplasma sp. And Theileria sp. A few samples were only found to be positive for Babesia sp. infection. Significantly higher rate of infection was observed in the female animals. Species-specific PCR revealed different tick-borne pathogens species viz. Babesia bigemina, Theileria orientalis, Theileria annulata, Anaplasma marginale, Anaplasma central and Anaplasma bovis in cattle. Isolated DNA samples from blood and ticks were found positive for Coxiella burnetii and Borrelia burgdorferi sensu lato by PCR assay, albeit at very low percentage. The results clearly indicate that vector-borne haemoprotozoa and rickettsia are prevalent in the study area in apparently healthy animals without showing any obvious symptoms and R.(B.)microplus tick has an endosymbiotic relationship with C. burnetii and B. burgdorferi sensu lato.