First detection of Theileria equi in free-roaming donkeys (Equus africanus asinus) in Sri Lanka.

The study reports the first detection of Theileria equi, a pathogen causing tick-borne disease equine piroplasmosis, in the free-roaming donkeys in Sri Lanka. The findings highlight the importance of monitoring the donkey population to prevent the disease’s spread.

Background

• Equine piroplasmosis (EP) is a tick-borne disease affecting equids, including horses, donkeys, zebras, and mules. It is caused by two pathogens, Theileria equi and Babesia caballi, and impacts the equine industry globally.
• Carrier animals infected with these pathogens can serve as infection sources for ticks, complicating disease management.
• Despite Sri Lanka being a tropical country with common tick-borne parasites, infections by T. equi and B. caballi are unexplored.

Objective and Methodology

• The study undertook an epidemiological survey to investigate the presence of T. equi and B. caballi pathogens in free-roaming donkeys in Sri Lanka.
• Blood samples from 111 donkeys across Mannar and Kilinochchi districts were collected and subjected to microscopic examination and DNA screening.
• Species-specific PCR assays were utilized to check for T. equi and B. caballi infections.

Findings

• T. equi presence was confirmed in 57.7% and 85.6% of the donkeys via microscopy and PCR test respectively, while no B. caballi infections were detected.
• The study also identified two distinct genotypes, C and D, of T. equi through phylogenetic analysis of the 18S rRNA sequences.

Significance

• This research marks the first report of T. equi in Sri Lanka and the first detection of genotype C in donkeys.
• These findings stress the importance of continuous monitoring of the donkey population in Sri Lanka to control EP disease. Moreover, the detection of T. equi highlights the inherent risk of potential spread to the human population and other livestock.