Risk clusters of Schistosoma mansoni infection in an endemic state of Brazil: space–time modelling and association with socio-economic and environmental factors

Abstract

Background We analysed the spatial distribution and the socio-economic and environmental factors (SEFs) associated with Schistosoma mansoni infection in the state of Alagoas, an important tourist area in northeastern Brazil. Methods We conducted an ecological time-series study (2007–2016) on schistosomiasis cases and SEFs. We evaluated the temporal trends of schistosomiasis cases (annual percentage change [APC]) and their correlation with SEFs. Spatial analysis maps were built using QGIS and TerraView software. Results We observed that 4.9% of the municipalities had a high prevalence of S. mansoni infection and were located mainly in the coastal strip of Alagoas state. The positivity rate for schistosomiasis decreased during the period (8.1% in 2007 to 4.9% in 2016; APC=−5.71). There was a reduction in the number of tests performed (APC=−5.05). There was a negative correlation between S. mansoni infection and the municipal human development index (ρ=−0.34) and schooling rate (ρ=−0.24). The main species of snail was Biomphalaria glabrata (94.79%), but Biomphalaria straminea showed a higher percentage of S. mansoni detection (10.11%). Lastly, Biomphalaria tenagophila specimens were identified for the first time in Alagoas (n=28). Conclusions Despite a reduction in the number of cases, intestinal schistosomiasis still represents a serious public health concern in Alagoas. It urgently requires planning and improvements in diagnosis, prevention programs and the state's socio-economic indicators.

Challenges to Schistosomiasis Control Program in Brazil: setbacks in the control program and critical analysis of the disease notification

“…The PCE operates in a decentralized manner, with actions planned and organized at the municipal level, and mandated for inclusion in the basic healthcare plan 8 , 11 , 12 . Brazil utilizes two notification systems for schistosomiasis cases: in endemic areas are registered in the Information System of the Schistosomiasis Surveillance and Control Program (SISPCE) and severe cases are registered in the Information System of the Notification of Diseases (SINAN).…”