Comparative efficacy of different in vitro cultivation media for Trypanosoma evansi isolated from different mammalian hosts inhabiting different geographical areas of India

The present study was undertaken to establish an optimal medium for primary culture initiation and maintenance of T. evansi isolated from different mammalian hosts of diverse geographical regions of India viz. donkey/1 (Hardoi, Uttar Pradesh), donkey/2 (Junagarh, Gujarat), pony/1 (Hisar, Haryana), camel/1 (Bikaner, Rajasthan) which represented isolates 1, 2, 3 and 4, respectively. Primary cultures were initiated with all four isolates in five different in vitro cultivation media with seeding density of 1 × 10⁶ trypanosomes/ml. The parasites of all four isolates could remain viable only for 48 h in medium E (Alsever’s solution) and for 72 h in medium A, C and D. Parasites reached to a maximum density (2.5–3.75 × 10⁶/ml) within 24 h and thereafter, a sharp decline (0.5–0.75 × 10⁶/ml) in the next 72 h was observed in 1, 2 and 3 isolates cultured in medium B. In isolate 4, parasite counts got more than doubled in 24 h and then decreased gradually up to sixth day post initiation of cultivation which thereafter increased gradually up to 34 days and a constant parasite number of 10⁵/ml could be achieved for 90 days in medium B. During this prolonged culture the trypanosomes retained their long slender morphology and infectivity to mice.