Meningoencephalitis in naturally occurring Trypanosoma evansi infection (surra) of horses.

This study explores the impact of a disease called surra, caused by the parasite Trypanosoma evansi, on horses. Despite trypanocidal therapy, the disease led to a fatal outcome for five mature horses over eight months. The focus was on a specific aspect of surra: lesions in the central nervous system, an area previously not well-studied despite indications of likely impact there.

Overview of the Disease and Study

• The research focuses on Surra, a disease widely prevalent in areas including North Africa, Asia Minor, Southeast Asia, and Central and South America. This disease affects various domestic and wild species, but horses and camels are particularly susceptible.
• The study investigates the lesions, particularly neural ones, caused by the disease. Previous investigations have primarily been cursory in nature.

Details of the Study

• The study reviewed case reports and specimens of five mature horses that died over eight months despite receiving trypanocidal therapy.
• Effects of the disease included varied degrees of anemia, ventral edema, lethargy, ataxia, and moderate pyrexia, especially in the early stages. The average duration of the signs was about two months.
• Trypanosomes consistent with T. evansi were found in the fresh blood smears from four horses. The remaining horse was found to be similarly affected after passage in mice.

Post-mortem Analysis

• Necropsies showed non-specific changes in the horses’ bodies, such as emaciation with ventral edema, slight subcutaneous or serosal hemorrhages, and edematous, enlarged lymph nodes.
• The brain scans of some horses indicated a few scattered petechiae in the meninges of the cerebellum and brain stem.
• Autopsy examination revealed a general, non-suppurative meningoencephalitis affecting white and gray matter across all levels of the brain.

The article hints at large-scale implications of surra and the importance of understanding its impact, particularly on the central nervous system.