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Introduction
According to Grove (1989), the genus Strongyloides Grassi, 1879 includes 52 species of nematode parasites of vertebrates. Domestic mammals, including cats, dogs and farm animals such as cattle, sheep and pigs, are the main hosts for Strongyloides spp. However, few species of Strongyloides have been reported in amphibians, reptiles and birds (Dorris et al., 2002).
Strongyloides spp. have a complex life cyle which includes a parasitic and a free-living generation. Hosts become infected when free-living infective third-stage larvae (L3) penetrate the skin. These larvae migrate through the host's body and, during this migration, they moult via an L4 stage so that there are adult parasitic female worms present in the gut. The eggs are produced and passed to faeces. In the host faeces the eggs hatch to release first-stage larvae. These L1s have alternative potential developmental fates. In one, they develop via L2-L4 stages into rhabditiform male and female worms, i.e. the free-living adult generation. This type of development is known as indirect, sexual or heterogonic development. The alternative fate of the L1s that hatch from eggs passed in faeces is that they moult via an L2 into infective L3s. This type of development is known as direct, asexual or homogonic development (Viney & Lok, 2007).
In Brazil, Strongyloides ophidiae Pereira, 1929 and Strongyloides cruzi Rodrigues, 1968 have been reported to infect reptiles. The former was described in a snake Mastigodryas bifossatus Raddi, 1820 (Pereira, 1929) and the second in a gecko Hemidactylus mabouia Moreau de Jonnès, 1818 (Rodrigues, 1968). Pereira (1929) described S. ophidiae; however, only parasitic females and the eggs were analysed in this species description. Since then, no other S. ophidiae report has been published. Rhabditoid and filarioid larvae, as well as free-living male and female forms of this nematode, were not studied.
Recently, molecular studies have been accomplished for the characterization of Strongyloides spp. (Dorris & Blaxter, 2000; Dorris et al., 2002; Hasegawa et al., 2009). However, these studies did not include snake Strongyloides species from Brazil. In the present study, we present morphological and molecular data for S. ophidiae, collected from the snake Oxyrhopus guibei Duméril & Bibron Duméril, 1854.
Material and methods
Source of nematode materials
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