Occurrence of Biomphalaria tenagophila and Disappearance of Biomphalaria straminea in Paracambi, RJ, Brazil

Abstract

The transmission of Schistosoma mansoni in different localities at the municipality of Paracambi, State of Rio de Janeiro, Brazil, appeared to implicate Biomphalaria straminea as the only intermediate host since the 70s, according to the records of the Fundação Nacional de Saúde (FNS). In March 1975, WL Paraense (1986 in Modernos conhecimentos sobre esquistossomose mansônica, Biblioteca da Academia Mineira de Medicina, 12 pp.) identified B. straminea in Paracambi, and the specimens were deposited in the Malacologic Collection of the Oswaldo Cruz Institute. However, following a more recent epidemiological study of schistosomiasis in Sabugo (MS Soares et al. 1995 Mem Inst Oswaldo Cruz 90: 451-458) initiated in January 1990, the exclusive presence of B. tenagophila, infected with S. mansoni, was reported. Consequently, the present study was undertaken to ascertain the distribution of potential snail hosts in the municipality. The study, started in 1990, paid special attention to sites where B. straminea had been previously reported by the FNS and also to sites where cases of schistosomiasis had been reported. The snail breeding sites studied were located in: Centro,