Freshwater gastropods of the Baixada Maranhense Microregion, an endemic area for schistosomiasis in the State of Maranhão, Brazil: I - qualitative study

• Published in: Revista da Sociedade Brasileira de Medicina Tropical
• Main Authors: Selma Patricia Diniz Cantanhede, Monica Ammon Fernandez, Aline Carvalho de Mattos, Lângia Colli Montresor, Nêuton Silva-Souza, Silvana Carvalho Thiengo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT) 2014
• Subjects: Freshwater snails; Schistosoma mansoni; Vectors; Baixada Maranhense Microregion; Brazil; Cercaria; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doi.org/10.1590/0037-8682-0194-2013; https://doaj.org/article/3847fd5e280a4230afbb73d736649c67

Introduction: The Baixada Maranhense Microregion currently has the highest prevalence of schistosomiasis in the State of Maranhão, likely because this parasitosis is characterized as an occupational disease, and increased contact with water increases the risk of infection by Schistosoma mansoni. This paper reports the results of the first comprehensive freshwater malacological survey performed in the Baixada Maranhense Microregion. Methods: Freshwater mollusks were collected from the twenty-one municipalities of the Baixada Maranhense Microregion and from Bacurituba and Cajapió and were evaluated for infection by trematodes. Results: A total of 9,129 mollusks were collected (sixteen species), which included the first records of six species in the State of Maranhão: Gundlachia radiata, G. ticaga, Hebetancylus moricandi, Plesiophysa guadeloupensis, Pomacea bridgesii diffusa and Omalonyx sp. Biomphalaria glabrata was found in five municipalities, whereas B. straminea was found in nine. Biomphalaria glabrata and B. straminea were observed in syntopy in Pinheiro and São Bento. Of the 990 specimens of B. glabrata and the 2,109 specimens of B. straminea that were exposed to and/or analyzed for the presence of larval trematodes, only a single specimen of B. glabrata (0.1%) from São Bento shed S. mansoni. Other larval trematodes were first observed in mollusks from the State of Maranhão. Conclusions: These results indicate that the study area is epidemiologically important due to the presence of two natural vectors of schistosomiasis and the active transmission of schistosomiasis, which was confirmed in the infected specimen that was collected in this study.