The Pampulha reservoir remains a potential urban focus of schistosomiasis mansoni in Brazil: changes in the occurrence patterns of Biomphalaria species and a new record of the parasite

Abstract

Introduction:The Pampulha reservoir has long been a focus of schistosomiasis transmission in Belo Horizonte, State of Minas Gerais, Brazil. The last malacological study conducted in this urban reservoir was more than two decades ago, and thus, an update on the distribution of the species of Biomphalaria as well as new data on the presence of Schistosoma mansoni in this water body are required. Methods: The current distribution of Biomphalaria spp. in the Pampulha reservoir and their infection with S. mansoni was evaluated during 55 malacological surveys conducted between 2009 and 2012. Results: Biomphalaria straminea displayed a high population density and distribution, and 13.7% (2,233/16,235) of the specimens collected were infected with larval trematodes other than Schistosoma mansoni. Biomphalaria tenagophila and Biomphalaria glabrata, species currently presenting a restricted distribution and small populations, displayed trematode infection rates of 15.2% (98/644) and 13% (83/640), respectively. Thirteen (2%) specimens of B. glabrata were found to be infected with S. mansoni. In addition, a historical review based on previous and new data on the occurrence patterns of Biomphalaria species in this reservoir is presented. Conclusions: The results indicate that the Pampulha reservoir remains a potential focus of urban schistosomiasis in Brazil, and signifi cant changes in the occurrence patterns of Biomphalaria species were verifi ed.

A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species

“…Three species of Biomphalaria that play a role in the transmission of S. mansoni in Brazil were recently found in the Pampulha reservoir, which is a potential urban focus of schistosomiasis located in the municipality of Belo Horizonte, State of Minas Gerais 12 .…”

Population Structure and Dynamics of Helminthic Infection: Schistosomiasis

“…Schistosomiasis transmission is generally considered a problem of rural areas, and in Brazil, for example, major cities are not usually considered endemic for transmission. Yet infected individuals can be identified at low prevalence in major cities of the endemic regions of Brazil (88–90) and Africa (91, 92). The public health response should differ depending on the relative contribution of immigration or local transmission.…”

The changing profile of schistosomiasis in a changing urban landscape

“…Now the cities themselves are changing and, with them, the profile of the disease. Urbanisation of schistosomiasis is recognised as a growing problem in Africa (Sarda et al, 1985;Ernould et al, 2000;Matthys et al, 2010;Mwakitalu et al, 2014;Dabo et al, 2015), and it has been well documented in Brazil (Barreto, 1960;Guimaraes et al, 1993;Barbosa et al, 2011Barbosa et al, , 1998Guimaraes and Tavares-Neto, 2006;Coura-Filho, 2005;Oliveira et al, 2013;Pinto et al, 2013;Blanton et al, 2015;Calasans et al, 2018;). Studies in Brazil (Brooker et al, 2006) and China (Shen et al, 1997) indicate there are significant differences between rural and urban schistosomiasis.…”