RESUMO
Exposure to parasites is considered to be an important factor in the development of many diseases and histopathologies which are the result of the parasite-host interaction. The present study evaluated the impact of natural infection by larvae of Ortleppascaris sp. (Nematoda: Ascaridida) in the liver of the cane toad Rhinella marina (Linnaeus, 1758). Larvae were encysted in nodules delimited by collagenous fibers and fibroblasts or freely within the hepatic parenchyma, provoking a clear response from the host. The histological examination of the liver revealed viable larvae in a number of different developmental stages, as well as cysts filled with amorphous material and cell residues and surrounded by dense fibrotic tissue. The infection of the liver by these larvae induces a significant increase in the area occupied by melanomacrophages and a reduction or deficit in the vascularization of the liver, hypertrophy of the hepatocytes, vacuolar bodies, and cytoplasmatic granules. Focal concentrations of inflammatory infiltrates were observed enclosing the unencapsulated early-stage larvae. These results indicate that infection by Ortleppascaris sp. induces severe physiological problems and histopathological lesions in the liver of R. marina .
Assuntos
Infecções por Ascaridida/veterinária , Ascaridoidea/fisiologia , Bufo marinus/parasitologia , Hepatopatias Parasitárias/veterinária , Fígado/patologia , Animais , Infecções por Ascaridida/patologia , Grânulos Citoplasmáticos/patologia , Hepatócitos/parasitologia , Hepatócitos/patologia , Hipertrofia , Células de Kupffer/patologia , Fígado/irrigação sanguínea , Fígado/parasitologia , Hepatopatias Parasitárias/patologia , Macrófagos/parasitologia , Macrófagos/patologia , Vacúolos/patologiaRESUMO
This study presents a new record for the occurrence of larval Ortleppascaris sp.(Sprent, 1978). The nematodes were collected from inside fibrous cysts found in the livers of cane toads, Rhinella marina (Linnaeus, 1758), captured in eastern Brazilian Amazonia. This is the first record of Ortleppascaris sp. larvae in both Brazil and this amphibian host, increasing its distribution in South America as well as expanding the number of helminths known to infect this toad. The detailed description of Ortleppascaris sp. provides new taxonomic data for these larvae, as well as sequences of the internal transcribed spacers and small subunit DNA segments, and the cytochrome oxidase I gene, which will, in time, contribute to a better understanding of the phylogeny of this group of parasites.