Analysis of the dynamics of Trypanosoma evansi strain accumulation during laboratory cultivation

Abstract

Background: The aim of the study was to characterise the accumulation dynamics, viability, morphology, and antigenic suitability of Trypanosoma evansi during experimental infection in mice and cultivation in RPMI-PY medium.

Methods: The study was conducted from January to June 2025 in the parasitology laboratory of the Limited Liability Company Scientific-Production Enterprise Antigen using experimental infection of male mice followed by morphological, culturological, and serological analysis of the pathogen.

Results: The results demonstrated a clear dependence of the infection course and morphological characteristics of the pathogen on the inoculum dose and cultivation conditions. At the lowest inoculum dose, parasitemia in mice reached approximately 4.80? cells/mL; at the medium inoculum dose, it reached 1.10? cells/mL; and at the highest inoculum dose, it reached up to 1.30? cells/mL, accompanied by intensified clinical signs. Morphometric analysis revealed a reduction in cell length from 24.6 ?m at the lowest inoculum dose to 20.3 ?m at the highest inoculum dose and a reduction in flagellum length from 8.2 to 6.1 ?m, along with an increase in the proportion of degenerative forms and kinetoplast displacement. In in vitro culture, growth exhibited an S-shaped pattern: from 6.80? cells/mL on day five to a peak of 1.30? cells/mL on day nine, followed by a decline in viability to 6 %. Protein analysis showed a concentration of 2.3 mg/mL with dominant antigenic fractions around 30 and 55 kDa, confirming the diagnostic value of the obtained material.

Conclusion: The results demonstrated dose-dependent changes in parasitemia, morphology, in vitro growth, and protein profile of T. evansi, highlighting the diagnostic and applied significance of the study.

Keywords

Surra, Antigens, Protein fractions, Serological test, Diagnostics, Cells, Anemia