Criação de caramujos infectados para obtenção em massa de cercárias e esquistossômulos

Abstract

A routine to maintain infected snails Biomphalaria glabrata able to produce 1-2 million cercariae per week and a mean shedding of about 3,500 cercariae per snail was quantitatively described. To a monthly production of about 5.3 and 6.5 million cercariae during the years of 1982 and 1983 it was necessary to expose an average of 1,557 and 1,957 snails, respectively. The efficiency described was maintained by infecting 2,000 snails per month (infectivity index of about 60%). A maximal production of 6,000 cercariae/snail was obtained in the period between 56-70 days after the snail infection by miracidia. By this period, however, 90% of the infected snails were dead. In the summer of 1982-1983 it was observed an impairment on the daily cercarial harvests which was related to ambient temperature increase, and the presence of rotifers in the aquaria water. When the cercariae were transformed into schistosomula in vitro, a yield of 55% schistosomula was obtained, with 7% of tail contamination. Lyophilization of cercariae produced 50.9 +/- 63 g dry weight per 1,000 cercariae.

Tópicos em Malacologia Médica

“…Brumpt (1941) usou na sua técnica de criação, alface crua macerada. Alface seca ou fresca continuou sendo oferecida, principalmente para manutenção de caramujos paralelamente ao uso de outras hortaliças (Barbosa & Silva, 1951;Chernin & Michelson, 1957;Szumlewic, 1958;Souza et al, 1985;. Também foram usadas rações de fórmulas bastante eficientes como a de Standen (1951) que sofreu modificações significativas, dentre elas as de Moore et al (1953) e Pellegrino & Katz (1968).…”

“…ou mesmo com a própria alface seca pulverizada. Os melhores resultados, contudo, têm sido obtidos com uso de ração e alface, outras plantas e perifiton com complementação (Santos, 1985;Bronmark, 1989; Barbosa et al, 1992;Souza et al, 1985). O efeito crowding, resultante da elevada densidade de moluscos, nos recipientes de criação, responsabilizado pela queda de crescimento e de fecundação nas colonias, pode ter sido confundido com falta de OD e de alimento em quantidade adequada, pois quanto maior a densidade menor a disponibilidade de perifiton por caramujo.…”

Rearing of Lymnaea columella (Say, 1817), intermediate host of Fasciola hepatica (Linnaeus, 1758)

“…In the present study, the methodology used to rear L. columella in the laboratory was the same as that used for B. glabrata mass growing (Souza et al 1985(Souza et al , 1987, with satisfactory results (Tables I, II). Initially, in addition to lettuce and powered ration, algae and the aquatic plant (Lemna sp.)…”

“…The snails in aquarium A were fed fresh lettuce and in B, fresh lettuce plus rodent powered ration (Purina®) + 10% CaCO 3 ; the latter diet has already been used to feed Biomphalaria in our laboratory (Souza et al 1985(Souza et al , 1987. The paste ration was placed on the lettuce leaves.…”