Molecular epidemiology and phylogenetic characterisation of Theileria luwenshuni in India: A first report

Abstract

We describe the first report of Theileria luwenshuni in India and its molecular characterisation by 18S rRNA gene based phylogenetic analysis. During the year 2015–16 and 2016–17, many sheep and goat flocks in Karnataka state of India witnessed mortalities ranging from 20 to 60%, with symptoms of high fever, anaemia and weakness. The ailing animals did not respond to routine treatments. The present study describes screening of blood samples of clinically ailing as well as in-contact, apparently healthy animals in these affected flocks. During this study, blood samples and ticks were collected from 106 sheep and 47 goats in nine districts of Karnataka state, India. Microscopic examination revealed presence of Theileria spp. in 53 sheep and 32 goats. Theileria genus specific PCR targeting amplification of 1098bp region on 18S rRNA gene showed presence of Theileria spp. in 103 sheep and 45 goats. Species specific PCR employed for detection of the most common Theileria spp. prevalent in India viz., T. ovis and T. lestoquardi did not yield specific amplifications. Hence, 1098bp genus specific PCR amplicons were subjected for nucleotide sequencing and phylogenetic analysis. The phylogenetic analysis showed that the Theileria spp. identified during this study had >99.9% sequence identity with T. luwenshuni isolates of Chinese origin. PCR detected T. luwenshuni in 103 sheep and 45 goat samples. The ticks collected from sheep and goats during this study were identified as Haemaphysalis kutchensis, Haemaphysalis intermedia, Haemaphysalis bispinosa, Rhipicephalus haemaphysaloides and Rhipicephalus sanguineus. This is the first report on detection and molecular phylogenetic characterisation of T. luwenshuni in small ruminants of India.