[Outbreaks of equine trypanosomiasis caused by Trypanosoma evansi in Formosa Province, Argentina].

The research article discusses about the outbreak of equine trypanosomiasis caused by Trypanosoma evansi in horses in Formosa Province, Argentina. The study used techniques such as centrifuging microhaematocrit capillary tubes and the direct agglutination test on blood and serum samples respectively. The parasite responsible for the disease was found in a significant number of animals from eight herds.

Study Sample and Research Method

• In the study, blood samples from 257 horses from 21 herds in Formosa Province of Argentina were tested.
• The researchers used the technique of centrifuging microhaematocrit capillary tubes to detect the presence of Trypanosoma evansi, the parasite causing the disease.
• The direct agglutination test was also applied to serum samples from the same animals to detect antibodies to T. evansi.

Key Findings

• Out of 137 animals from eight herds, T. evansi was discovered in 90 animals. This suggests that a considerable number of horses were afflicted by the disease.
• Further validating the disease’s spread, antibodies to T. evansi were found in 107 horses. This signifies that the horses’ bodies were actively fighting the infection, indicating the disease’s presence.
• Antibodies were also detected in nine horses from two herds where the parasite was not detected. This could imply that these horses were potentially exposed to the disease or had possibly cleared the infection.

Geographical Spread and Impact

• ‘Mal de caderas,’ the condition caused by T. evansi, was found to be occurring in both humid (eastern) and sub-humid (central) zones of Formosa. These zones are home to more than 95% of the equine population of the province (57,000 horses). This highlights the severity and scale of the outbreak as these zones are densely populated with potential hosts.

Disease Strains and Characteristics

• In six strains of T. evansi, maintained by passage in mice, between 3% and 20% of the parasites were found to possess a kinetoplast. This information provides insight into the varied morphological characteristics of the T. evansi parasite.