Estudo epidemiológico prospectivo para monitoramento de cães utilizando coleiras impregnadas com deltametrina como parte do Programa de Vigilância e Controle da Leishmaniose Visceral em áreas de transmissão em Minas Gerais

Abstract

Visceral leishmaniasis (VL) is a severe disease transmitted by phlebotomine sand flies and a public health problem in Brazil. To combat it, the country adopted the Visceral Leishmaniasis Surveillance and Control Program, which includes measures such as vector control and the euthanasia of infected dogs. In 2021, the Ministry of Health began distributing insecticide-impregnated collars for dogs in priority municipalities, such as Ipanema, Minas Gerais, to reduce disease transmission and its impact on Collective Health. This study evaluated the impact of using these collars in Ipanema during the years 2022 and 2023. The objective was to analyze the effectiveness of the canine collaring program, characterizing the exposed canine population of the region, identifying the causes of loss of insecticide collars, analyzing the rate of refusal to the program and evaluating its results. The longitudinal and prospective study followed the guidelines of Technical Note number 5/2021 of the Ministry of Health. The areas of operation were defined considering the incidence of VL between 2017 and 2020, canine prevalence and socioeconomic vulnerability. The canine population was estimated at one dog for every seven humans, as recommended by the World Health Organization and the Pasteur Institute. Dogs residing in the selected areas, with a minimum age of three months and whose guardians agreed to undergo the rapid test, were candidates to receive the collars. The study included the exchange of collars and the inclusion of new dogs, in addition to the application of questionnaires about the characteristics of the animals and reasons for loss of the collars, which were classified into different categories. In the two cycles of the program, the profile of the dogs was 58% female and 42% male, predominantly adults and small-sized collars were the most used. In the first cycle, 1023 dogs (58% of the estimated population) were tested, and 1001 (97% of those tested) received collars. In the second cycle, 879 dogs were evaluated and 824 (94%) received collars. Of these, 70% participated in the first cycle. Refusals (6%) were mostly justified by allergy (80%). A 73% reduction in canine positivity for VL was observed in the studied areas. In the first cycle, 34 dogs tested positive, 18 were euthanized and 16 were treated. In the second, this number dropped to nine, with only one euthanized. Of the dogs that participated in both cycles, 390 (56%) lost their collars, mainly due to loss caused by the animal itself (66%), followed by allergy (14%), others (11%) and theft (9%). Despite the promising results, the study highlights challenges such as collar loss and the need to improve communication with the community. Health education actions and continuous monitoring are essential for the long-term success of the program.