THE INFECTIVITY AND VIRULENCE OF TRYPANOSOMA EVANSI IN LOCAL INDIAN DAIRY X KEDAH.KELANTAN CATTLE

O. ABAS MAZNI and A.H. ZAINAL-ABIDIN

Abstract

A strain of Trypanosoma evansi (TE) was recently isolated from swamp buffalloes at Bukit Ridan Station, MARDI, Pahang in West Malaysia. Some studies were carried out on the local cattle to determine the infectivity and virulence of the parasite. Six local cattle, Local Indian Dairy x Kedah-Kelantan (LID x KK), were infected subcutaneously with 5.0x 10 TE per animal. It was found that the local cattle were susceptible to this parasite. Intense parasitaemia in the blood persisted until 34 days post infection. A rise in the body temperature was observed in all infected animals but only at the initial stage of the infection. However, it was found that the rise in parasitaemia did not coincide with the rise in the body temperature. Changes in the haematological pictures (RBC, PCV and Hb) were also observed. Recovered animals were challenged with a double dose i .e. 1.0 x 10⁸ TE. 290 days after the initial infection. It was found that all the animals showed a delayed parasitaemia (i.e. three days later) as compared with the parasitaemia in the control. Intermittent fever also occurred in these animals.

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