The clinical implications of Theileria sp. Yokoyama, a recently identified Theileria species in cattle, remain uncertain. The objective of the present study was to evaluate the anemia status in cattle infected with Theileria sp. Yokoyama. Blood samples were collected from 206 cattle across seven Veterinary Ranges in Sri Lanka and analyzed for red blood cell (RBC) indices, including hemoglobin concentration, hematocrit, and RBC counts. Additionally, DNA was extracted from the samples and screened with a newly developed Theileria sp. Yokoyama-specific PCR assay targeting the cytochrome b gene. The PCR results revealed that 60 (29.1%) of the surveyed cattle tested positive for Theileria sp. Yokoyama, with 47 (78.3%) of them being co-infected with other hemopathogen species. Our findings revealed that the cattle breeds, management systems, and tick infestations are potential risk factors for the Theileria sp. Yokoyama infection. Next, we evaluated the anemia status among the surveyed cattle based on the RBC indices. We found that all non-infected cattle were non-anemic. By contrast, anemia was observed in 15 Theileria sp. Yokoyama-infected cattle, including 3 singly infected (anemia rate 3/13, 23.1%) and 12 co-infected cattle (12/47, 25.5%). Our findings suggest that Theileria sp. Yokoyama causes anemia in infected cattle.

The goat industry plays an important role in Sri Lanka’s rural economy, with farms predominantly concentrated in the dry and intermediate zones. The industry’s popularity has increased over time due to low investment costs and high economic returns. Several parasitic diseases have been described in goats, including theileriosis, caused by pathogenic protozoa of the genus Theileria. A few cases of theileriosis have been reported from the Veterinary Surgeon’s Division, Ampara. Following a detailed investigation, Theileria luwenshuni was isolated from affected animals, indicating the possibility of infection among other animals in the herd. Therefore, the present study was designed and implemented to conduct molecular screening and identify risk factors associated with pathogenic Theileria species in goats in the Ampara and Uhana Veterinary Surgeon’s Divisions. A total of 125 whole blood samples were collected from randomly selected goats across the study area. Demographic information, including sex, age and degree of tick infestation, was also recorded. DNA was extracted from the blood samples, and PCR was performed using specific primers for Theileria lestoquardi, Theileria uilenbergi and Theileria luwenshuni. The results revealed a 22.4% prevalence of Theileria luwenshuni in the study, while the other two parasites were absent. Moreover, sex and tick infestation were identified as potential risk factors, with a statistically significant association with disease prevalence (p < 0.05). Three samples identified as positive for Theileria luwenshuni were subjected to sequencing and deposited under accession numbers PZ306778, PZ306779 and PZ306780 in the GenBank database. BLAST analysis of the 18S rRNA gene sequences obtained in this study revealed sequence similarities ranging from 98.08% to 100% with reference sequences from different animal hosts and geographical locations in the NCBI GenBank database. Most notably, the present isolate showed a 100% identity score with the Theileria luwenshuni isolate from Jaffna sheep, indicating a potential risk of local transmission of the pathogen between host species.