Biomphalaria spp. (Preston, 1910) snails in the municipality of Juiz de Fora, Zona da Mata Mineira mesoregion, ate of Minas Gerais, Brazil

Abstract

This study focuses on the geographic distribution of the snail of the genus Biomphalaria and evaluates its infectivity byOf the state's 853 municipalities distributed in the 12 political-administrative mesoregions, 283 have been studied for the snail's prevalence. B. glabrata has been reported in 65.3% of the municipalities studied; B. straminea in 43.8%; B. tenaghophila in 20.4%; B. peregrina in 20.1%; B. schrammi in 9.2%; B. intermedia in 7%, and B. occidentalis in 0.7% . The municipality in Brazil is the local political-administrative division, corresponding roughly to a county or prefecture. It is governed by a mayor and municipal council. Some municipalities are almost completely urbanized, others almost totally rural, and some, like Juiz de Fora, a mixture of the two.The most recent scientific report on the occurrence of Biomphalaria in Juiz de Fora municipality, the main social and economic center in the state's Zona da Mata So, this work focuses on the geographic distribution of Biomphalaria in Juiz de Fora municipality with identification of the species found, possibility of infectivity, and main types of related habitats. This updated study of the occurrence of intermediate hosts in the region confirms, for the first time, the presence of B. straminea in the municipality, with the study of this snail susceptibility of the Juiz de Fora strain to S. mansoni. MATERIALS AND METHODSLocation under study -This study was carried out in the municipality of Juiz de Fora (21S14/42W14), in the mesoregion known as the Zona da Mata Mineira, Minas Gerais, Brazil (Fig. 1). This municipality is located 280 km from Belo Horizonte, the state capital, and 184 km from the city of Rio de Janeiro. Juiz de Fora has a land area of 1,429.875 km 2 , with a population of 419,226 inhabitants according to the 2000 census. The municipality, with an average altitude of 800 m, has an ample hydrographic basin rich in lakes, ponds, and irrigation ditches. The spatial localization of the foci was determined by instant positioning from a GPS (Global Positioning System) apparatus.Malacological survey -These surveys were performed in collaboration with technicians from DADS/Juiz de Fora (Directorate for Decentralized Health Actions, an organ of the State Health Secretariat). The specimens were collected from lotic and lentic ecosystems in the municipality, predominantly around the urban perimeter, where the characteristics are favorable to the occurrence and spatial dispersion of snails near human populations. We captured the specimens with the aid of tongs and nets. The study was conducted in 2003 to 2004.Snails -After collection, the snails were taken to the laboratory where the living specimens were measured. After examination under artificial light for S. mansoni cercarie, the snails were submitted to squeezing between glass plates to detect the presence of cercariae. Some specimens were separated for morphological identification (Paraense 1975). Another sample of specimens was packed and sent to the René-Rachou Research Center for mole...

Schistosoma mansoni and other larval trematodes in Biomphalaria tenagophila (Planorbidae) from Guarulhos, São Paulo State, Brazil

“…identification of cercariae: All snails were put individually into the wells of 12-well tissue culture plates (Nalg Nunc International) and exposed to artificial light (for two to three hours) for five days intervals under a stereomicroscopy to determinate the possible infection with trematode larvae. In addition, snails were individually pressed between two glass plates to detect the presence of larvae 40 . The cercariae were identified under light microscopy and confocal microscopy (Laser Scanning Microscopy, LSM 510 META, Zeiss) at 488 nm (exciting) and 505 nm (emission) based on the morphological characteristics, swimming behavior and resting position as described by FRANDSEN & CHRISTENSEN 15 , SCHELL 32 and RUIZ 29,30 .The larvae were observed "in vivo" and fixed in Formalin-acetic-alcohol solution (F.A.A.).…”

Malacological survey of Biomphalaria snails in municipalities along the Estrada Real in the southeast of the State of Minas Gerais, Brazil

“…The presence of Biomphalaria species was previously reported in the municipalities of Piau, Rio Novo and Juiz de Fora 15,18,31 , although considering their geographical location, only Juiz de Fora has been surveyed 18 . Models to estimate the prevalence of schistosomiasis have been perfomed in the State of Minas Gerais 14,[32][33][34] and in some Estrada Real municipalities 16 , but in both studies, due to lack of georeferenced information for Biomphalaria, only data concerning the prevalence of human schistosomiasis and Biomphalaria species in relation to the municipality were used.…”

“…Little information exists regarding the prevalence of schistosomiasis in the municipalities studied, because the region is generally considered to be of low endemicity 18 . The presence of Biomphalaria species was previously reported in the municipalities of Piau, Rio Novo and Juiz de Fora 15,18,31 , although considering their geographical location, only Juiz de Fora has been surveyed 18 .…”

“…Of these, 36 were included in the study. The core urban area of the City of Juiz de Fora was not included, because the results of a local malacological survey conducted prior to this study had already been published 18 .…”

The use of spatial tools in the study of Schistosoma mansoni and its intermediate host snails in Brazil: a brief review

“…The relatively large number of S. mansoni intermediate hosts in Brazil, all with different degrees of susceptibility to infection, together with the continued spread of snails into new localities and the large number of potentially suitable snail habitats have fostered a strong and persistent interest in the geographic and temporal distribution of different species of Biomphalaria. Published studies range in scale from the South American subcontinent and Brazil (Paraense, 1986(Paraense, , 2001Souza et al, 1997) to the State (Bavia et al, 2001;Souza et al, 2001) and community (Souza et al, 1998;Thiengo et al, 2001;Kloos et al, 2004;Tibirica et al, 2006) levels. Most spatial studies mapped snail infections or correlated snail distributions to schistosomiasis prevalence with the objective of identifying highrisk areas, communities and human-water contact sites (Carvalho et al, 2003;Barbosa et al, 2004;Kloos et al, 2004;Araújo et al, 2007).…”