Spatiotemporal analysis and environmental risk factors of visceral leishmaniasis in an urban setting in São Paulo State, Brazil

Abstract

Background In Latin America, Brazil harbors the most cases of human visceral leishmaniasis (HVL). Since the early 1980s, the disease has spread to the urban centers of the north, and now the south and west of Brazil; it reached São Paulo state in the southeast in 1996, and Presidente Prudente in the western region in 2010. Our aim was to describe the spatiotemporal analysis and environmental risk factors associated with the dispersion of VL in Presidente Prudente, an urban setting with recent transmission. Methods An entomological survey was carried out from 2009 to 2015. A canine visceral leishmaniasis (CVL) serosurvey was performed from 2010 to 2015 using enzyme-linked immunosorbent assays (ELISA), a dual-path platform CVL rapid test, and indirect fluorescent antibodies (IFAT). Data from HVL cases were obtained from the Municipal Surveillance Epidemiology Center from 2013 to 2017. Data on water drainage and forest fragments were obtained from public platforms and irregular solid-waste deposits were determined by monthly inspections of the urban area. Kernel density maps of the distribution of CVL were constructed. Results From 2009 to 2015, Lutzomyia longipalpis sand flies were found in all seven areas of Presidente Prudente. From 2010 to 2015, 40,309 dogs were serologically screened and 638 showed positive results, i.e. a prevalence rate of 1.6%. From 2013 to 2017, six human cases were diagnosed with a mortality rate of 33.3%. In 2015, 56 points of irregular solid-waste deposits were identified, predominantly in the neighborhoods. Three different hotspots of CVL showed an increased distribution of vectors, seropositive dogs, irregular solid-waste deposits, forest fragments and water drainage. Conclusions The use of tools that analyze the spatial distribution of vectors, canine and human VL as environmental risk factors were essential to identifying the areas most vulnerable to the spread or maintenance of VL. The results may help public health authorities in planning prevention and control measures to avoid expansion and future outbreaks.

Multiscale environmental determinants of Leishmania vectors in the urban-rural context

“…Of course, urban services, paved streets or distance to the river are not modifiable variables but other variables were associated with “hot spots” at different scales including the microscale site of collection. For instance, the recommendations could include planned vegetation coverage with selected tree species, few plant-pots and deforested belts to increase the distance from forest edge, improved quality of houses (openness), garbage management and water drainage, reduced accessibility to chickens or other blood-meal sources (by increasing the distance from pens to house) [ 5 , 7 , 20 , 21 , 53 – 56 ].…”

Cases and distribution of visceral leishmaniasis in western São Paulo: A neglected disease in this region of Brazil

“…However, following the Candido Rondon highway (BR300), the disease crossed the state from the western region to the east toward the capital [ 6 ]. In the 45 municipalities of RNHA11 mesoregion, in the western region of São Paulo, in the border of MS, the first phlebotomine systematic collection was found in Dracena, a city located in the north and considered the epicenter [ 7 ]. In 2020, the western region harbored 537 of 3042 (17.6%) individuals infected with VL in São Paulo [ 4 ].…”

Double Trouble: Dengue Followed by COVID-19 Infection Acquired in Two Different Regions: A Doctor’s Case Report and Spatial Distribution of Cases in Presidente Prudente, São Paulo, Brazil

“…The reasons why rates of dengue are continuously increasing in the region are not well established. It is alarming that, in 2018 and in 2020, 56 and 58 irregular solid-waste deposits were found in the urban area along the river basins and in vacant household lots, respectively [13]. Incorrect disposal and storage of domestic waste by the population, increasing temperatures, deforestation [14], and Aedes aegypti mutations [15] are certainly environmental and socioeconomic factors that may contribute to the increase in the number of cases in Presidente Prudente, and they can be extended to the 45 municipalities of the western region (Figure 1A-C).…”

“…In 2020, in Presidente Prudente, the largest and most important city in the western region of São Paulo (Figure 1E), an outbreak of dengue was on course in the first months of the year at the same time as the COVID-19 pandemic was emerging. Based on our previous findings of vulnerable niches for dengue and visceral leishmaniasis [13], we hypothesized that, in these settings, a possible association of dengue in the context of COVID-19 cases was occurring. Identifying these areas would guide public health authorities in surveillance measures and improvements in health care infrastructure.…”