Taxonomia de Contracaecum (Nematoda: Anisakidae) parasito de Phalacrocorax brasilianus (aves, phalacrocoracidae) na reserva extrativista marinha de Soure, Ilha de Marajó, Pará.

Abstract

The occurrence of endoparasites in water birds is a relevant issue, as they can promote major changes in local dynamics, due to their high capacity for displacement and dispersion. The cormorant (Phalacrocorax brasilianus) is one of the most abundant piscivorous birds in South America, and in Brazil it is adapted to different aquatic ecosystems. Among these, we highlight the natural landscapes of the marine extractive reserve of Soure, composed of areas of floodplains, igapós, flooded fields, mangroves with marine influence and estuarine beaches. In their natural environment, animals may be prone to parasitosis, such as helminthiases, so studies on helminths allow us to know the parasite diversity, their ecological indices of parasitism and add epidemiological data on occurrence and distribution in the Amazon region. This work identified nematodes of the Contracaecum genus, parasites of P. brasilianus (Aves, Phalacrocoracidae) from the marajoara ecosystem. Twenty specimens of cormorants were examined during the period from April 2020 to February 2022, captured and provided by riverine fishermen in the municipality of Soure. The birds were examined at the Laboratory of Animal Histology and Embryology - LHEA - UFRA. The nematodes collected were quantified for analysis of ecological indices of parasitism and processed for analysis by light microscopy, scanning electron microscopy and representative specimens were used for molecular characterization whenever possible. Of the 20 samples analyzed, 90% (n=18) were parasitized by Contracaecum spp., with a mean intensity of infection of 41.2; mean abundance of 37.1 and amplitude ranging from 3-360 parasites per host. Regarding the site of infection, the ventricle was the organ most affected by parasitism caused by Contracaecum 88.9% (n=16). Morphological analysis of adult individuals allowed us to assign them to five distinct taxa: one corresponding to C. australe, also molecularly characterized, confirming the parasitism in P. brasilianus, expanding the geographic distribution of this parasite, which is the first record of the species in Brazil. Furthermore, morphological analyzes revealed the existence of Contracaecum sp. 1, its morphological characters strongly support the hypothesis that it is a new species of the Contracaecum genus. Other taxa identified through morphological analysis were assigned to three other distinct species: C. rudolphii s. l., C. multipapillatum s. l. and C. microcephalum confirming the presence of these species in P. brasilianus in the Marine Extractive Reserve of Soure, Pará-Brazil.