Validation of a new experimental model for assessing drug efficacy against infection with Trypanosoma equiperdum in horses.

The researchers developed and validated a new experimental model for assessing the efficacy of drugs against the infection caused by Trypanosoma equiperdum in horses.

Overview of Research Article

This study focuses on the development and validation of an experimental model for testing how effective drugs are against Trypanosoma equiperdum, a parasite that causes dourine, a disease in horses.

• The parasite is known to affect the central nervous system, leading to neurological signs in those infected.
• This location protects the parasite from the majority of existing chemotherapies. Consequently, the OIE terrestrial code considers dourine a non-treatable disease, which typically calls for euthanizing the infected animal.
• The lack of suitable tools for studying the effectiveness of treatments has impeded the progress of alternative strategies for managing dourine.

Development of the Experimental Infection Model

• The researchers developed an infection model by infecting horses with Trypanosoma equiperdum and then using an ultrasound-guided cervical sampling protocol to look for trypanosomes in the cerebrospinal fluid (CSF).
• The model involves inoculating 5 × 10^6 T. equiperdum OVI parasites intravenously into adult Welsh mares.
• After developing the model with four horses, the researchers tested its efficacy on eight additional horses, introducing the parasites through the same process.

Results of the Experimental Infection Model

• All eight horses showed parasites in their blood by the second day following inoculation, and in their CSF around 12.5 days afterwards.
• Seroconversion, the time period during which a specific antibody develops and becomes detectable in the blood, was also detected approximately 8.25 days after inoculation.
• All horses developed fever and low hematocrit, indicating a low concentration of red blood cells, in addition to ventral edema, a swelling caused by excess fluid accumulated in the horses’ tissues.
• Less common clinical signs including edema of the vulva and cutaneous plaques were observed in some of the horses.

Conclusion of the Research

The researchers concluded that the model provides a robust infection protocol that creates a severe infection and allows observes parasites in the CSF of infected horses in a timeframe compatible with animal experimentation parameters. It is a suitable tool for analyzing the effectiveness of anti-Trypanosoma drugs and vaccines.