Rearing of Lymnaea columella (Say, 1817), Intermediate Host of Fasciola hepatica (Linnaeus, 1758)
Vol. 95(5): 739-741, Sep./Oct. 2000
Cecília Pereira de Souza+, Kelly Grace Magalhães++
Laboratório de Malacologia, Centro de Pesquisas René Rachou-Fiocruz, Av. Augusto de Lima 1715, 30190-002 Belo Horizonte, MG, Brasil
The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7°C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory
Key words: fasciolosis - Lymnaea columella - intermediate host - Minas Gerais - Brazil - rearing techniques
The geographic distribution of Lymnaeidae is very wide in Brazil (Paraense 1982a,b, 1983, 1986). In Minas Gerais, Lymnaea columella specimens from Sete Lagoas, Santa Rita do Sapucaí, Viçosa and Belo Horizonte municipalities were found to be susceptible to experimental infection with Fasciola hepatica miracidia (Dacal et al. 1988). Recently, Silva et al. (1995) reported the first natural infection of L. columella with F. hepatica in Itajubá, southern of Minas Gerais. In a malacology survey performed in 13 municipalities in the Belo Horizonte microregion, L. columella was found in eight: Pedro Leopoldo, Lagoa Santa, Santa Luzia, Vespasiano, Ribeirão das Neves, Belo Horizonte, Nova Lima and Betim (Souza et al. 1998).
This study initiated the rearing of L. columella, collected in Belo Horizonte. The aims of the study were to standardize a breeding and maintenance technique for these snails collecting data on growth, oviposition, number of eggs per egg mass, egg incubation period and longevity. In the future, these snails will be submitted to experimental infection with F. hepatica in order to obtain the eggs, cercariae, metacercariae and the adult worms to study vaccine production.
ACKNOWLEDGEMENTS
To Professor Roney Elias da Silva from the Departamento de Parasitologia, Universidade Federal de Minas Gerais, for collecting and providing the snails. To Dr Wladimir Lobato Paraense from the Departamento de Malacologia, Instituto Oswaldo Cruz, Rio de Janeiro, for the specific identification of the snails. To Dr Neusa Araújo from the Laboratório de Esquistossomose, Centro de Pesquisas René Rachou, for the statistical analysis.
+Corresponding author. Fax:+55-31-295.3115. E-mail: souzacp@netra.fiocruz.br
++Research fellow CNPq
Received 18 August 1999
Accepted 9 February 2000
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