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Domestic, synanthropic and wild hosts of Leishmania spp. parasites were studied in an area endemic for American tegumentary leishmaniasis (ATL), specifically in northern Minas Gerais State, Brazil. Domestic dogs and small forest mammals are reservoir hosts for L. (Leishmania) infantum. However, the role that these animals play in the transmission cycle of the Leishmania spp. that cause cutaneous leishmaniasis is not well known. This study evaluated 72 rodents, 25 marsupials and 98 domestic dogs found in two villages of the Xakriabá Indigenous Territory, an area of intense ATL transmission. A total of 23 dogs (23.47%) were shown to be positive according to at least one test; 8 dogs (8.16%) tested positive in a single serological test and 15 dogs (15.31%) tested positive by IFAT and ELISA. Eleven dogs were euthanised to allow for molecular diagnosis, of which nine (81.8%) tested positive by PCR for Leishmania in at least one tissue. Seven animals were infected only with L. (L.) infantum, whilst two displayed a mixed infection of L. (L.) infantum and L. (V.) braziliensis. Isoenzymatic characterisation identified L. (L.) infantum parasites isolated from the bone marrow of two dogs. Of the 97 small mammals captured, 24 tested positive for Leishmania by PCR. The results showed that L. (V.) braziliensis, L. (L.) infantum and L. (V.) guyanensis are circulating among wild and synanthropic mammals present in the Xakriabá Reserve, highlighting the epidemiological diversity of ATL in this region.

The existence of free-roaming dogs raises important issues in animal welfare and in public health. A proper understanding of these animals’ ecology is useful as a necessary input to plan strategies to control these populations. The present study addresses the population dynamics and the effectiveness of the sterilization of unrestricted dogs using capture and recapture procedures suitable for open animal populations. Every two months, over a period of 14 months, we captured, tagged, released and recaptured dogs in two regions in a city in the southeast region of Brazil. In one of these regions the animals were also sterilized. Both regions had similar social, environmental and demographic features. We estimated the presence of 148 females and 227 males during the period of study. The average dog:man ratio was 1 dog for each 42 and 51 human beings, in the areas without and with sterilization, respectively. The animal population size increased in both regions, due mainly to the abandonment of domestic dogs. Mortality rate decreased throughout the study period. Survival probabilities did not differ between genders, but males entered the population in higher numbers. There were no differences in abundance, survival and recruitment between the regions, indicating that sterilization did not affect the population dynamics. Our findings indicate that the observed animal dynamics were influenced by density-independent factors, and that sterilization might not be a viable and effective strategy in regions where availability of resources is low and animal abandonment rates are high. Furthermore, the high demographic turnover rates observed render the canine free-roaming population younger, thus more susceptible to diseases, especially to rabies and leishmaniasis. We conclude by stressing the importance of implementing educational programs to promote responsible animal ownership and effective strategies against abandonment practices.

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