IMMUNIZATION OF DOGS, HAMSTERS AND GUINEA-PIGS AGAINST RHIPICEPHALUS-SANGUINEUS USING CRUDE UNFED ADULT TICK EXTRACTS

Naive experimental groups of dogs, hamsters and guinea pigs were inocu lated three times subcutaneously with unfed adult extract of the tick Rhipicephalus sanguineus and challenged with adult R. sanguineus to ev aluate resistance. The acquisition of resistance was based on alterati ons of some reproductive and feeding performance parameters of female ticks such as female and egg mass weights, engorgement, pre-ovipositio n and incubation periods, larval hatchability rate and efficiency rate s of female ticks in converting their food reservoir to eggs and larva e. Dogs did not develop resistance under these experimental conditions ; guinea pigs and hamsters, to a lesser extent, acquired an effective immunity to ticks as demonstrated by the impairment of the reproductiv e and feeding performance. However, the resistance induced by inoculat ion of the extract in the rodents seemed not to be as efficient as tha t induced by successive infestations.