Recent Progress in the Detection of Surra, a Neglected Disease Caused by Trypanosoma evansi with a One Health Impact in Large Parts of the Tropic and Sub-Tropic World

Abstract

Surra is a wasting disease triggered by infection with Trypanosoma evansi, a protozoan blood parasite that causes mortality and morbidity in a broad spectrum of wild and domestic animals and occasionally humans. Trypanosoma evansi has the widest geographical spread among all pathogenic trypanosomes, inflicting significant worldwide economic problems due to its adverse effects on meat and milk production. For diagnosis, most endemic countries continue to rely on traditional parasitological and serological techniques, such as the analysis of blood smears by microscopy and the Card Agglutination Test for T. evansi (CATT/T. evansi). Although these techniques suffer from a limited positive predictive value (PPV), resource constraints in endemic countries often hinder the adoption of more advanced diagnostic tools such as PCR. This paper addresses diverse diagnostic approaches for identifying T. evansi and assesses their viability in field settings. Moreover, it underscores the urgency of transitioning towards molecular diagnostic techniques such as Loop-Mediated Isothermal Amplification (LAMP) and Recombinase Polymerase Amplification (RPA) for dependable high-PPV point-of-care (POC) diagnostics. Finally, this review delves into strategies to enhance and refine next-generation diagnostics for Surra as part of a One Health approach.

Investigation into Trypanosoma evansi Infection in Horses in East Sumba-Indonesia

“…The two different seroprevalence within the same location of study and using the same assay of CATT, may be associated with seasonal reason, as one factor, although no association mainly between sex and age was reported (Benaissa et al 2020;Sana et al 2022). Using several methods for diagnosing T. evansi in horses, the CATT method was considered the most appropriate choice and sensitive for serological surveys, it can give the highest rate (14.4%) compared to PCR (1.3%) and WOOS test (0.5%), suggesting the PCR and the WOOS test were more specific, so that the seropositive status of animals should be further confirmed using the PCR method on satellite DNA targets (Tehseen et al 2017;Kim et al 2024). However, in this study there was 100% association between the microscopy and the CATT analysis, indicating that the animals under investigated were in acute parasitemia phase with a high quantity of T. evansi in the circulating blood, and the CATT predominantly detect IgM during this stage of disease progression (Chandu et al 2021).…”

“…With the high mortality, as no vaccine for Surra, suggesting no effective anti surra treatment was applied during the outbreak, although prolonged survival of the infected animals may helped by the increased production of antiinflammatory IL-10 (Nguyen et al 2023). Therefore, the only appropriate prevention strategy was suggested by understanding and implementing epidemiological approach, including an appropriate control vectors (Kim et al 2024).…”

“…The specific potency of every test should be evaluated carefully for effective application based on the different epidemiological conditions. Many researchers have compared several diagnostic techniques such as using PCR, CATT and serological assays (Tehseen et al 2017;Kim et al 2024). Detection of T. evansi through blood smear is very dependent on the amount of parasitemia that occurs.…”

Parasitological and serological detection of Trypanosoma evansi on Bali cattle at the Pesanggaran slaughterhouse, Denpasar, Indonesia using hematological profile

“…Trypanosoma evansi infection in cattle generally occurs subclinically (Chandu et al 2021). It is often challenging to find parasites in the blood circulating in the periphery (Kim et al 2023), as the infection tends to be chronic (Behour et al 2019), or there is no high parasitemia (Nurcahyo 2017). Internal factors also play a role in influencing test results, namely host conditions.…”