Abstract
Theileria annulata (T. annulata) is a tick-borne apicomplexan parasite affecting ruminants and causes severe economic loss. The present paper reports the vertical transmission of T. annulata in a three day old crossbred Jersey calf. Molecular diagnosis of tropical theileriosis was done by PCR, cloning, sequencing and phylogenetic analysis of isolated parasites. Calf showed very low hematocrit value (HCT) (17.82%), red blood cells count (RBC) count (6.9 × 10(6)/μL), and hemoglobin concentration (Hb) (6.6 g/dL). Phylogenetic analysis of Tams 1 gene showed that T. annulata Khorda isolate (MW123091) shared 99.23%, 99.23% and 99.11% nucleotide homology with Puri, India (MN818858), Bahrain (AF214797) and Hyderabad, India (MK034702), respectively. This is the first study in Odisha, India to give an insight into the molecular detection, phylogeny and hematological analysis of T. annulata infected crossbred Jersey calf which got the infection through transplacental transmission.