Authors

R McCrone¹; M Barrett¹; H Auty¹; R Ritchie¹; G Rossi¹; C Regnault¹; S Richards²; I Eastwood³; C Solino³; O Manangwa⁴; F Mramba⁴; PS Buyugu⁴;  ¹ University of Glasgow , UK;  ² International Livestock Research Institute, Kenya;  ³ ELUCEDA ltd, UK;  ⁴ Vector and Vector Borne Disease Institute, Tanga, Tanzania

Discussion

Animal trypanosomosis, encompassing both African animal trypanosomosis (AAT) and Surra, poses a major threat to livestock health and rural livelihoods across sub-Saharan Africa. While AAT is caused by Trypanosoma congolense, T. vivax, and T. brucei brucei, Surra is caused by T. evansi and is mechanically transmitted by biting flies. Despite differing transmission modes, both diseases are commonly treated with the same trypanocidal drugs and are increasingly affected by treatment failure linked to counterfeit pharmaceuticals.

This study investigates the prevalence and detection of counterfeit veterinary trypanocides in Northeastern Tanzania. During field sampling of Handeni and Pangani districts, 112 trypanocides were collected (August 2024) and analysed using HPLC as the gold standard. Chemical analysis of trypanocide samples found that 43.5% of isometamidium chloride (ISM) formulations were counterfeit or substandard, lacking sufficient active pharmaceutical ingredient (API). Such subtherapeutic drug exposure may contribute to treatment failure and create selective pressure for resistance emergence.

A novel portable electrochemical detection device (E-Sens™) was evaluated for its ability to identify suspect formulations rapidly and in the field. Classification outcomes were highly comparable between methods: for diminazene aceturate (DA), 96.6% of samples met quality thresholds by HPLC compared with 95.5% using the device. For ISM, both methods identified similarly low compliance rates (56.5% by HPLC; 52.2% by E-Sens™), reflecting the high prevalence of substandard products. The device showed strong concordance with high-performance liquid chromatography (HPLC) and mass spectrometry in detecting samples with inadequate API content, supporting its potential as a low-cost, field-adaptable screening tool.

These findings highlight the need for improved drug quality surveillance in veterinary trypanosomosis. Portable detection technologies may strengthen counterfeit monitoring efforts and help mitigate one contributor to treatment failure in endemic regions such as Tanzania.