ABSTRACT
This study aimed to characterize the prevalence, mean abundance, and mean intensity of potential fish-borne zoonotic nematode larvae infecting the predator fish Hoplias aff. malabaricus from the Tapajós River, in the municipality of Santarém, in the Brazilian Amazon. After capture, the specimens of H. aff. malabaricus were analyzed for infection by Contracaecum sp. and Eustrongylides sp. third-stage larvae, and the prevalence, mean abundance, and mean intensity were calculated. A literature search was carried out to clarify the relationship between these indicators and eventual human cases of infection in the Amazon region. Third-stage larvae of nematodes of the Contracaecum and Eustrongylides genera were found in the specimens of H. aff. malabaricus sampled from the Tapajós River. The prevalence of Contracaecum larvae was 100%, while its mean abundance and mean intensity were both 54.8 larvae/fish. The prevalence of Eustrongylides larvae was 62.9%, and its mean abundance and mean intensity were 1.8 and 2.8 larvae/fish, respectively. Despite the high prevalence and intensity values, there are no cases of human infection by these nematode larvae in the Brazilian Amazon reported. The absence of human infections by these nematode larvae in the Brazilian Amazon despite the high prevalence/intensity of Contracaecum and Eustrongylides larvae and the high consumption of fish in the region, is most probably due to the fact that the local populations do not eat raw or undercooked fish. However, it is noteworthy that the absence of zoonotic cases in the region is based only on the examination of the available published papers. A better knowledge of the situation would require surveying hospitals and clinics, and data from the region's medical treatment facilities. However, the authors consider that cases of human infection, if any, are extremely rare, mainly due to the eating habits of the local population.
Subject(s)
Humans , Animals , Zoonoses , Fishes , Infections , LarvaABSTRACT
ABSTRACT During a survey conducted in the Lajeado Reservoir of the Tocantins River, in the state of Tocantins, Brazil, dactylogyrids were recovered from the gills of Pimelodina flavipinnis. Initial morphological analysis showed these dactylogyrids shared aspects of character with species of Demidospermus, with affinity to Demidospermus pinirampi, despite exhibiting differences with the original description by Kritsky et al. (1987) regarding the vagina, the base of the male copulatory organ and the shape and length of the bars. The analysis of the holotypes of D. pinirampi and its most morphologically close species, Demidospermus luckyi, revealed that these dactylogyrids were indeed D. pinirampi. This study therefore reports a new host and locality of occurrence, and reviews some measurements of the original description, supplementing and enhancing the morphological diagnosis of D. pinirampi.
RESUMO Durante um levantamento realizado no Reservatório de Lajeado, no Rio Tocantins, no estado de Tocantins, Brasil, dactilogirídeos foram recuperados das brânquias de Pimelodina flavipinnis. A análise morfológica inicial mostrou que esses dactilogirídeos compartilham aspectos de caráter com espécies de Demidospermus, com afinidade com Demidospermus pinirampi, apesar de apresentarem diferenças em relação à descrição original fornecida por Kritsky et al. (1987) com respeito à vagina, à base do órgão copulatório masculino e à forma e comprimento das barras. A análise dos holótipos de D. pinirampi e de sua espécie morfologicamente mais próxima, Demidospermus luckyi, revelou que estes dactilogirídeos eram realmente D. pinirampi. Este estudo, portanto, relata um novo hospedeiro e localidade de ocorrência e revisa algumas medidas da descrição original, complementando a diagnose morfológica de D. pinirampi.