Biological and environmental factors associated with risk of schistosomiasis mansoni transmission in Porto de Galinhas, Pernambuco State, Brazil

Onicio Batista Leal Neto,Elainne Christine De Souza Gomes,Fernando José Moreira De Oliveira Junior,Diego Leandro Reis,Constança Simões Barbosa,Silvana Bocanegra,Reinaldo Souza-Santos,Rafael Andrade

doi:10.1590/s0102-311x2013000200022

Abstract

Schistosomiasis has expanded to the coast of Pernambuco State, Brazil, where there are frequent reports of Biomphalaria glabrata snails and human cases of the disease. This study analyzes factors related to schistosomiasis transmission risk in Porto de Galinhas. A one-year malacological survey was conducted to identify biological, abiotic, and environmental factors related to the host snail breeding sites. Data analysis used Excel 2010, GTM Pro, and ArcGis 10. A total of 11,012 B. glabrata snails were captured in 36 breeding sites, and 11 schistosomiasis transmission foci were identified. A negative correlation was found between breeding site temperature and snail density and infection rate, and a positive correlation with pH and salinity. The rainy season showed a positive correlation with snail density and infection rate. The study emphasizes the factors involved in the maintenance of schistosomiasis breeding sites, in light of persistence of this disease in Porto de Galinhas for more than 10 years.

Highlights

Schistosomiasis is considered one of the most prevalent infectious-parasitic diseases in the world [1,2]
11 were classified as schistosomiasis transmission foci since they harbored snails infected with S. mansoni, totaling 272 positive snails
The snail population density and monthly infection rate were correlated with the monthly means of the following abiotic parameters measured in all the B. glabrata breeding sites: temperature, salinity, and pH

Summary

Introduction

Schistosomiasis is considered one of the most prevalent infectious-parasitic diseases in the world [1,2]. This waterborne parasite infection has the helminth Schistosoma mansoni as the etiological agent and a heteroxenous life cycle, with humans as the definitive hosts and snails from genus Biomphalaria as the intermediate hosts. Northeast Brazil is country’s most heavily endemic region, with Alagoas, Sergipe, Bahia, and Pernambuco as the States with the highest prevalence of the disease 5. Pernambuco is the State of the Northeast with the third highest prevalence of human cases of the disease 6 and with the occurrence of two vector snail species, Biomphalaria glabrata and Biomphalaria straminea [7,8]. On the State’s coastline there have been various reports of these species colonizing non-natural and peridomiciliary aquatic environments: pools of rainwater, open-air wastewater, and flooded empty lots [11,12,13,14], demonstrating the snails’ capacity to adapt to different habitats

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Results

Conclusion