Molecular Prevalence, Associated Risk Factors, and Genetic Characterization of Theileria Ovis in Sheep and Goats.

BACKGROUND

Theileria species is an important tickborne pathogen of sheep and goats globally. This study was performed in western Saudi Arabia to investigate the prevalence, associated risk factors, and phylogenetic analysis of Theileria ovis (T. ovis) in sheep and goats.

METHODS

A total of 300 blood samples, 190 from sheep and 110 from goats, were collected. The investigation was performed using PCR targeting the small subunit ribosomal RNA (ssu rRNA) gene, in addition to genetic characterization.

RESULTS

The proportion of goats and sheep testing positive was variable ranging from 9.1 to 13.2%. The total prevalence of T. ovis was found to be 9.1% in goats and 13.2% in sheep. The enrolled sheep and goats were confirmed to be infected with T. ovis by sequencing the partial ssu rRNA gene, and a similar genotype was identified. Age, housing, sex, and tick infestation factors were significantly associated with the infection (p < 0.05). Multivariable model analysis indicated that T. ovis infection was 4.6, 0.4, 3.1, and 8.2 times higher in ages > 1 year, females, closed housing, and tick infestation, respectively. Phylogenetic analysis and high nucleotide identities revealed similar genotypes of T. ovis exist in the field, and were close to Turkish T. ovis (OM066225, a goat strain).

CONCLUSIONS

We reported a low to relatively moderate molecular prevalence of T. ovis in goats and sheep, respectively, from the western region. However, it is recommended to adopt control measures to reduce T. ovis infection in small ruminants in this area.