Prevalence and incidence of trypanosomosis in horses and donkeys in the Gambia.

The research article presents a study investigating the prevalence and occurrence of trypanosomosis, a parasitic disease, in horses and donkeys from two different regions in the Gambia.

Objective

The primary goal of this research was to understand the prevalence (how widespread) and incidence (the number of new cases) of trypanosomosis, a disease caused by parasites named trypanosomes, in horses and donkeys from two regions, Niamina East and Bansang South in the Gambia. The regions were chosen based on known varying levels of exposure to the tsetse fly, the insect vector transmitting these parasites.

Methodology

• A total of 78 animals – 11 horses and 67 donkeys – were examined monthly from August 1997 to September 1998.
• For tests, blood samples from these animals were gathered and checked for trypanosomes using two methods: the buffy-coat (BC) method, a laboratory technique for detecting the parasites, and Polymerase Chain Reaction (PCR), a technique used to amplify specific DNA fragments for detecting the presence of certain species of the trypanosome parasites.
• Three different sets of primers were used in PCR to detect different species of Trypanosoma – vivax (TVW), congolense (GOL), or brucei (ORPHON5J).

Findings

• The results indicated that horses had a higher prevalence (45.5%) and monthly incidence (16%) of trypanosome infections compared to donkeys (6.2% and 9%, respectively) according to the BC method.
• The PCR method yielded a higher number of detected cases, specifically seven times more than the BC method.
• Among the trypanosome species, Trypanosoma congolense was the most common, followed by Trypanosoma vivax and Trypanosoma brucei.

Conclusion

The findings from this study confirm that, despite facing similar exposure to the tsetse vector as horses, donkeys are significantly less susceptible to trypanosomosis. This reinforces earlier research findings and contributes to a better understanding of the disease dynamics in these specific animal populations that could influence strategies for disease management and control.