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RESEARCH NOTE Presence of Mermithid Larvae (Nematoda, Mermithidae) in Limax flavus and Sarasinula marginata (Mollusca, Gastropoda) in Brazil Silvana C Thiengo Depaflamento de Malacologia, Instituto Oswaldo Cruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil
Code Number: OC95069 Size of Files: Text: 4K Graphics: Photos (jpg) 31K / Halftones (gif) 33KKey words: Limaxflavus - Sarasinula marginam - slugs - mermithid nematodes According to GO Poinar (1976 J Parasitol 62: 843-844) mermithid nematodes are monoxenotks parasites, with a preparasitic (infective) juvenile which emerges from the egg and actively penetrates the body cavity of an invertebrate host (insects, molluscs, crustaceans, arachnids, and others). After a period of development within the host, the nematode emerges in the environment, when it molts to the adult stage. Free living adults mate, and females deposit eggs in the environment. Mermithid nematodes, parasitic in molluscs, have not been recorded from South America. DS Dundee (1977 J Parasitol 63: 590), reported finding mermithids in Veronicella ameghini (Gambetta, 1923) introduced in the US from Bra- zil: "Since the molluscs were introduced - probably from Brazil - the mermithids might also be introduced". For the past five years, I have examined molluscs searching for larvae of Angiostrongylus costaricensis Morera and Cespedes, 1971, and, incidentally, have found large mermithid larvae (Fig.) in the body cavity of some of them. The molluscs were collected near the dwellings of people reportedly suffering from abdominal angiostrongyliasis in two disjunct areas: Locality 1 - Uberlandia, State of Minas Gerais (18 56'S, 48 18'W), in the autumn and the spring of 1993 and 1994; and Locality 2 - Inhomirin, State of Rio de Janeiro (22 35'S, 43 10'W) in late winter and spring of 1994. When the slugs Sarasinula marginata (Semper, 1885) and Limax flavus (L.) were eviscerated
to be processed and examined for larvae of A. costaricensis, larvae of mermithid nematodes were found within their body cavity. The prevalence of the raermithid larvae was as follows: 0.37% (2 among 542) in S. marginata and 12.5% (3 among 24) in L. flavus from Uberlfundia; and 52.2% (12 among 23) from Inhomirim. All specimens of L. flavus harbouring the metmithid larvae were very young, whereas all the specimens of S. marginata were adults.
Mermithid larvae were also found outside, around or even emerging from the head region of the molluscs, as has been reported by Dundee (loc. cit.) in Veronicella ameghini. Voucher specimens were deposited in the Helminthological Collection of the Instituto Oswaldo Cruz, No. 32.977. Aknowledgements: to Dr William Slutz, Zoonosis Center of Uberlandia for allowing me to use their facilities during the field work, to Marcelo A Stortti for the technical assistance, to Drs W Lobato Paraense, Departamento de Malacologia, IOC, FIOCRUZ, Rio de Janeiro and JFR Amato, Universidade Federal Rural do Rio de Janeiro, for critically reviewing the manuscript.
Copyright 1995 Fundacao Oswaldo Cruz
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