Delayed-type hypersensitivity test for assessing tick-immune status of cattle in Zambia

Delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of Tonga calves in Zambia. The antigen used in the tests was a homogenate of unfed nymphal Rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female R appendiculatus. There was a significant negative correlation between the intensity of the reactions and the total number of ticks (Amblyomma variegatum, R appendiculatus, Hyalomma truncatum, Boophilus decoloratus and Rhipicephalus species) on the animals.