Situação atual da esquistossomose mansoni no Lago da Pampulha, Belo Horizonte, MG, Brasil

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

“…The data obtained in the present study demonstrate that B. straminea is currently found at all sites evaluated, often with a high population density. Furthermore, B. straminea was the only species found in places previously colonized by B. tenagophila and/or B. glabrata, as reported by Carvalho et al 15 and Freitas et al 17 . Determining the factors related to the replacement and current distribution of B. straminea will require additional studies.…”

“…This species was originally reported at the Pampulha reservoir by Milward-de-Andrade 14 and soon became the predominant planorbid species in the locality, occupying the entire edge of the reservoir between the early 1980s and the 1990s 15,17,29 . This species of Biomphalaria was observed to be infected with S. mansoni at a very low rate, 0.03% (1/3,695), in the Pampulha reservoir by Carvalho et al 15 . Later, Souza et al 32 reported two specimens that were naturally infected by the parasite but did not provide an infection rate.…”

“…After the fi nding of S. mansoni in B. glabrata in the Pampulha reservoir in the 1930s, the reservoir was temporarily emptied, which resulted in the elimination of approximately 15 million specimens of B. glabrata. Since then, the species has been found in the reservoir with low population densities but continues to harbor larvae of S. mansoni [11][12][13]15,28 . In the early 1990s, B. glabrata was considered absent from the reservoir, although the species was present in tributary streams, and it was suggested that the occasional fi ndings of this species in the reservoir resulted from snails carried by rainfall runoff 17,29 .…”

“…Approximately three decades later, Paulini et al 10 obtained positive parasitological results from 18.7% of local residents in the same region. Given the presence of a transmission focus of schistosomiasis in the reservoir, several malacological studies that emphasize planorbids were also conducted at the Pampulha reservoir [11][12][13][14][15][16][17] . However, the latest published information dates to more than two decades ago; thus, an update is required.…”

Geographical distribution of Biomphalaria snails in the State of Minas Gerais, Brazil

“…In the mesoregions of Noroeste de Minas (V), Sul/Sudoeste de Minas (VIII) and Triângulo Mineiro/Alto Paranaíba (IX), where B. glabrata is rarely found, the occurrence of the parasitosis is very low (Figure). Although B. tenagophila is not widely spread in Minas Gerais, it was found naturally infected with S. mansoni in the municipalities of Jaboticatubas, Itajubá, Belo Horizonte and Ouro Branco (Melo & Pereira 1985, Carvalho et al 1985a,b, Silva et al 1994, localized in the mesoregions Metropolitana de Belo Horizonte (IV) and Sul/Sudoeste de Minas (VIII). The natural infection rates of this species in those focuses are low, ranging from 0.03 to 17.5%.…”