Antibody response to Trypanosoma evansi in camels of Kazakhstan

Аннотация

Surra, caused by Trypanosoma evansi, is a major constraint to camel health and productivity in arid and semi-arid regions. Despite Kazakhstan’s large camel population, peer-reviewed data on surra epidemiology remain scarce.

A cross-sectional seroepidemiological survey was conducted in two camel-breeding regions of Kazakhstan (Mangystau and Kyzylorda) during 2024 and 2025. Serum samples (n = 2,745 in 2024; n = 2,900 in 2025) were tested for anti-T. evansi antibodies using the complement fixation test (CFT) and the formol gel test (FGT). Seroprevalence was expressed with 95% confidence intervals (CI), and regional/temporal differences were assessed using Pearson’s chi-square test.

In Mangystau, CFT prevalence decreased from 5.0% (95% CI: 2.15–11.18) in 2024 to 0.78% (95% CI: 0.21–2.82) in 2025 (p = 0.0319), while FGT positivity declined from 65.0% to 5.88% (p < 0.001). Conversely, in Kyzylorda, CFT prevalence increased significantly from 4.0% (95% CI: 3.32–4.82) to 8.88% (95% CI: 7.87–10.01; p < 0.001), whereas FGT values rose slightly from 7.8% to 8.96% without statistical significance (p = 0.1504).

This study provides the first multi-year evidence of T. evansi circulation in camels in Kazakhstan, revealing contrasting regional dynamics: a sharp decline in Mangystau and a significant increase in Kyzylorda. These findings underscore the heterogeneous nature of surra epidemiology and highlight the need for continued surveillance and combined diagnostic approaches to inform control strategies.