Genetic characteristics of Theileria equi in zebras, wild and domestic donkeys in Israel and the Palestinian Authority.

This research explores the presence and genetic traits of Equine piroplasmosis (EP), a tick-borne disease, in domestic donkeys, wild donkeys, and zebras in Israel and the Palestinian Authority. The study findings suggest varying occurrences of the Theileria equi parasite in these animals, with domestic donkeys accompanying a different genotype than wild ones.

Study Design

• The research aim was to evaluate the presence of Equine piroplasmosis (EP) parasites such as Theileria equi and Babesia caballi in domestic donkeys, wild donkeys, and zebras in Israel and the Palestinian Authority.
• A total of 127 animals which included domestic donkeys, Asiatic wild donkeys, zebras, African wild donkeys, and mules were tested for subclinical EP infection using Polymerase Chain Reaction (PCR) and Quantitative PCR (qPCR) methods.
• When a positive sample was identified, it was further analyzed by amplifying and sequencing a 1600 bp fragment of the 18S rRNA gene, a characteristic genetic structure of these parasites.

Findings

• No traces of Babesia caballi were found in any of the animals.
• Theileria equi was detected in varying ratios in different animals: 32% of the donkeys, 89% of Asiatic wild donkeys, 57% of African wild donkeys, and 62% of zebras. It was not detected in any of the mule samples.
• Parasitemia, which is the level of parasites in the blood, was low across all positive samples.
• In donkeys, infection was associated with one particular farm (Kiryat Gat) and male sex.

Molecular Genetics

• The sequences of the 18S rRNA gene from domestic donkeys were found to be similar and belonged to Theileria equi genotype D. This genotype was akin to the one found in horses in the same area.
• Contrarily, sequences from wild donkeys were unique and belonged to Theileria equi genotype A.
• The Theileria equi genotype in zebras could not be definitively determined suggesting a significant genetic variation in these samples.

This study presents novel findings regarding the genetic characteristics and presence of EP in different types of equids in Israel and the Palestinian Authority. It underscores the importance of examining disease vectors among different species to better understand the spread and control of disease. The findings could influence the development of management strategies and treatments for Equine piroplasmosis.