Leishmaniose visceral canina: estudo epidemiológico e geoespacial, aspectos ecológicos e pesquisa de infecção natural em Lutzomyia longipalpis.

Abstract

Visceral leishmaniasis (VL) is a neglected tropical disease, with 94% of new cases distributed in countries like Ethiopia, India, Kenya, Somalia, Sudan, South Sudan and Brazil. Canine infection is indicative of risk for human infection, and due to the close interaction of dogs in the home environment, these animals become important reservoirs and source of infection. This thesis consists of three chapters. In chapter I, the prevalence of canine visceral leishmaniasis (CVL) in the municipality of Mãe D’Água was determined and the epidemiology of zoonosis was studied by analyzing the association factors and their distribution by georeferencing. For this, blood samples from 150 dogs, from urban and rural areas of the municipality, were collected. The prevalence of anti-Leishmania infantum antibodies was 18.6% (28/150), 10.6% (8/75) in the urban area and 26.6% (20/75) in the rural area. The rural area was identified as a risk factor (Odds ratio = 2.93); the permanence of the animal without restraint at night (Odds ratio = 0.33) and deworming (Odds ratio = 0.30) were classified as protective factors. The spatial analysis showed the formation of a primary risk cluster in the urban area (p = 0.010) located in the northern region of the municipality. In chapter II, an entomological and seasonal survey of sandflies was also carried out in the municipality of MãeD’Água. 567 sandflies were captured, 146 (25.7%) females and 421 (74.2%) males, and June 2019 was the month with the highest number of specimens collected (133 / 567- 23.4%). The species Lutzomyia lenti and Lutzomyia longipalpis were identified, this species being more prevalent in the rural area (487 / 493- 98.7%). The presence of Leishmania infantum DNA was detected in 4 (15.3%) of the 26 pools analyzed. The calculation of the Minimum Infection Ratio (MIR) rate demonstrated that 4% of females were positive. Chapter III aimed to describe the temporal and spatial distribution of cases of human visceral leishmaniasis (HVL) in the State of Alagoas, in order to identify areas of high risk of disease transmission from 2007 to 2018. The State is composed by 102 municipalities, of these, 68.62% (n = 70) reported at least one case of HVL in the 12 years studied. 489 cases of visceral leishmaniasis were recorded between 2007 and 2018, with an average of 40.7 cases per year and an incidence of 1.25/ 100 thousand inhabitants. Spatial dependence was detected in the second, third and fourth trienniums and similarity between the municipalities, but with a weak correlation and with high incidence clusters in the hinterland. It was evident that the State of Alagoas presented a marked geographical expansion of the HVL, making it necessary to prioritize areas and massify the actions of surveillance and epidemiological control.