Isolation, cloning, and pathologic analysis of Trypanosoma evansi field isolates

Area of Science:

• Veterinary Parasitology
• Infectious Diseases
• Livestock Health

Background:

• Emergence of highly pathogenic Trypanosoma evansi strains in the Philippines has led to substantial livestock production losses.
• Trypanosoma evansi causes significant economic impact on livestock globally.

Purpose of the Study:

• To isolate and analyze the virulence of Trypanosoma evansi strains from water buffaloes in the Philippines.
• To evaluate the pathogenicity of T. evansi strains in experimental mouse and cattle models.

Main Methods:

• Isolation of 10 T. evansi strains from infected water buffaloes.
• Virulence assessment in mice, measuring prepatent period, parasitemia, and survival.
• Experimental infection of cattle with selected T. evansi strains to evaluate pathogenicity and host response.

Main Results:

• Significant variations in virulence, prepatent period, parasitemia, and survival were observed among T. evansi strains in mice.
• Highly pathogenic strains induced splenomegaly, leukocytosis in mice, and anemia, decreased leukocyte counts, and TNF-α up-regulation in cattle.
• Pathogenicity in cattle mirrored findings in mice, with similar parasite growth rates and prepatent periods.

Conclusions:

• The epidemic of Trypanosoma evansi in the Philippines involves strains with a wide spectrum of virulence, from low to very high pathogenicity in cattle.
• Understanding strain-specific virulence is crucial for effective control and management of T. evansi infections in livestock.