Prevalence of Trypanosoma evansi in horses in Israel evaluated by serology and reverse dot blot.

This research article explores the prevalence of Trypanosoma evansi, the parasite causing surra, in the horse population in Israel. The study used serology, PCR, reverse dot blot technique, and blood smear microscopy to examine samples from 614 horses in 7 regions. The results revealed that surra is prevalent in most regions and should be considered an important differential diagnosis for certain clinical signs in horses and other domestic animals in Israel.

Study Background

• The study was conducted following the first outbreak of surra (a disease caused by a parasite called Trypanosoma evansi) in horses and camels in Israel in 2006.
• The aim of the research was to understand better the prevalence of the parasite in the Israeli horse population.

Methodology

• The researchers tested 614 horses from 7 different regions across the country.
• The tests used included serology, PCR followed by the reverse dot blot (RDB) technique, and blood smear microscopy.
• The CATT/T. evansi kit was used for all serology testing.
• Another round of sampling and testing was conducted a year later on horses from the Arava and Dead Sea regions, where the initial outbreak occurred.

Findings

• The overall prevalence of the parasite (based on seroprevalence) in the surveyed horse population was found to be 4.6%.
• The Arava and Dead Sea region had a slightly higher than the average seroprevalence of 6.5% in the first sampling, which dropped to 4.1% in the second sampling.
• The prevalence rate of RDB-positivity was remarkably high (18.7%) in the first sampling in the Arava and Dead Sea region, but it decreased drastically in the second sampling (0.8%).
• All tested horses were asymptomatic, with only one horse from the Arava and Dead Sea region showing clinical signs of surra, tested positive in serology and RDB.

Conclusions

• The findings of the study suggest that surra is prevalent in most regions across Israel.
• Therefore, the disease should be considered a significant differential diagnosis in horses and other domestic animals in Israel exhibiting symptoms such as chronic weight loss, edema, or neurological signs.