Exposure to and infection by Leishmania infantum among domestic dogs in an area of the Cerrado biome, Maranhão, Brazil.

Visceral Leishmaniasis is a serious public health problem and dogs are considered to be the main source of infection in urban areas. In Brazil, this disease is present in all regions, but with high concentration of cases in the Northeast, and the state of Maranhão is considered to be an endemic region. The aim of this study was to conduct an epidemiological, spatial, molecular and serological survey on Leishmania infantum among domestic dogs in the municipality of Belágua, Maranhão. Blood samples were collected from dogs and questionnaires were applied to their owners to obtain epidemiological data and risk factors relating to this zoonosis in the region. The coordinates of the dogs' homes were obtained to produce a disease risk map. Serological diagnoses were made using the indirect immunofluorescence reaction (IFAT) and the dual-path platform chromatographic immunoassay test (DPP®) (Bio-Manguinhos/FIOCRUZ, Brazil). A molecular investigation was undertaken using the polymerase chain reaction (PCR). Georeferencing was performed using the global positioning system (GPS) and cases of canine visceral leishmaniasis in the municipality were spatially represented and analyzed using QGIS version 3.16.6 (QGIS Development Team, 2021). A total of 205 blood samples were collected, of which 122 (59.51%) were seroreactive for L. infantum through IFAT, while the DPP test showed 84 reactive samples (40.97%). IFAT and DPP detected 16 positive animals simultaneously. One sample that was seroreactive through IFAT was also positive through PCR. In the clinical evaluation, it was observed that among the seropositive dogs, 112 (91.80%) were symptomatic and 10 (8.20%) were asymptomatic. In the spatial analysis, the Kernel density estimator enabled determination of the place at greatest risk of occurrence of the disease. The areas with the highest concentrations of cases were in districts with large quantities of precarious housing and lack of basic sanitation. This was the first report on the occurrence of L. infantum among dogs in the municipality of Belágua. The results show that canine visceral leishmaniasis is well dispersed in this municipality, thus putting at risk the human population.

Spatial and Seasonal Distribution of Holochilus sciureus with Schistosoma mansoni Infection in an Endemic Area for Schistosomiasis in Brazil.

INTRODUCTION: The occurrence of wild rodents in the Schistosoma mansoni life cycle may increase the transmission of schistosomiasis and understanding the spatial and seasonal distribution of the natural infection of these reservoirs is essential for the development of more effective control strategies. MATERIAL AND METHODS: In this study, Holochilus sciureus rodents were captured from the flooded fields of São Bento city (an endemic area for schistosomiasis in Northeast Brazil), during the dry and rainy seasons. All these sites were georeferenced and the prevalence of S. mansoni was verified by the presence of adult worms in the mesenteric branches and livers of each animal. RESULTS: It was demonstrated that almost half of the animals collected were naturally infected with S. mansoni (45.45%) and this infection was not related to the distance from urban areas. Furthermore, the temperature, precipitation, sex, and weight did not interfere with the H. sciureus infection rates. Interestingly, we found, for the first time, the natural infection of H. sciureus in another endemic city of S. mansoni in Northeast Brazil. CONCLUSIONS: Therefore, the H. sciureus rodent shows a high natural infection rate for S. mansoni in the flooded fields of São Bento, regardless of the weather station, capture distance, and biological aspects. Additionally, we have demonstrated that H. sciureus naturally parasitized with S. mansoni may inhabit a much more extensive area that is currently described in the literature.