HISTOPATHOLOGICAL CHANGES AT HYALOMMA-ANATOLICUM-ANATOLICUM FEEDING SITES ON TICK-RESISTANT CALVES

Studies were conducted in 7 crossbred (Bos taurus x Bos indicus) male healthy calves repeatedly infested with Hyalomma anatolicum anatolicum ticks, and in another 7 calves immunized with H.a. anatolicum salivar y gland antigen. All these calves developed significant resistance to infestation with H.a. anatolicum. To each of these 14 calves, 50 male and 50 female hungry adult H.a. anatolicum were attached to the ears u sing cotton-bags. Histopathological observations of skin biopsies reve aled formation of feeding cavities, cellular infiltration and epiderma l vesicles at the site of tick attachment. The cellular response there fore seems to be associated with the development of acquired resistanc e.