Experimental infection of Phlebotomus perniciosus and determination of the natural infection rates of Leishmania infantum in dogs.

Direct xenodiagnosis has been used to determine the infection rates in sand flies of 12 dogs parasitized by Leishmania infantum and classified in function of clinical signs. The dogs were divided into three clinical groups and no statistically significant differences in the infection rates of female sand flies were observed among them. This result indicates the epidemiological importance of asymptomatic and oligosymptomatic dogs. Indirect xenodiagnosis uses sand flies fed on the blood of dogs ex vivo. This technique was not found to be useful as an alternative to the direct method for the detection of dogs parasitized by L. infantum. The clinical worsening of the disease was not reflected in the increasing number of parasites detected in the animals' blood by the indirect technique, thereby rejecting its utility as an indicator of the prognosis of the disease.