Rate of Leishmania-induced skin-lesion development in rodents depends on the site of inoculation.

Regional differences in the response of mice to infection with three strains of dermotropic Leishmania spp. were shown for skin covering the trunk. Lesions tended to appear earlier and to grow more rapidly on sites over the caudal half of the body than the cranial half, and caudal lesions were more likely than cranial ones to result in metastatic disease in susceptible strains of mice. Site-related variations in lesion development were observed in different strains of mice as well as in golden hamsters. The effect of these regional differences on the development of some parasite-specific, immunological reactions was examined, as were parasite thermosensitivity and location-related variations in host skin temperature as possible explanations.