Improved Serodiagnosis of Trypanosoma vivax Infections in Cattle Reveals Higher Infection Rates in the Livestock Regions of Argentina

Bovine trypanosomiasis, caused by Trypanosoma vivax, currently affects cattle, resulting in significant economic consequences in sub-Saharan Africa and South America. The development of new diagnostic antigens is crucial for improving and refining existing methods. Our study assessed the effectiveness of two recombinant antigens in detecting specific antibodies in cattle. These antigens are derivatives of an invariant surface glycoprotein (ISG) from T. vivax. We evaluated a fraction of an antigen previously described (TvY486_0045500), referred to as TvISGAf, from an African strain, and identified a new ISG antigen from an American isolate, TvISGAm. ELISA evaluation using these antigens was conducted on 212 samples from cattle. The diagnostic performance was enhanced when utilizing a combination of both antigens (denominated TvISG-based ELISA), achieving a sensitivity of 89.6% and specificity of 93.8%. Following validation of the TvISG-based ELISA, we determined the seroprevalence of T. vivax infection in 892 field samples from cattle in the central region of Argentina. The average seroprevalence of T. vivax was 53%, with variation across the six surveyed departments ranging from 21% to 69%. These results support the use of the TvISG ELISA as a valuable serological tool for detecting and monitoring T. vivax infection in cattle. They also reported for the first time T. vivax seroprevalence in Argentina, highlighting the widespread endemic nature of the disease in the region. To effectively manage the increasing spread of T. vivax in the vast livestock production areas of South America, we support the need for consistent surveillance programs and implementation of preventive strategies.