THE GENUS Contracaecum (NEMATODA: ANISAKIDAE) IN MARAJÓ BAY: TAXONOMY AND MOLECULAR CHARACTERIZATION
Parasite; Anisakidae; Contracaecum; Phalacrocorax; Marajo
The occurrence of endoparasites in wild birds is a strong issue, as they are capable of promoting large changes in local dynamics, due to their high displacement and dispersion capacity. Phalacrocorax brasilianus is one of the most abundant piscivorous birds in South America, in Brazil it is adapted to various aquatic ecosystems, including the natural landscapes of the Soure marine extractive reserve, with floodplain areas, igapós, natural fields, mangroves with marine influence and estuarine beaches, favorable environments for the development of helminthiasis. Studies on helminths allow us to know about parasite diversity and its ecological indices of parasitism, making it possible to infer about its real potential as a dispersing agent and add epidemiological data on the occurrence and distribution of its parasites in the Amazon region. Therefore, the aim is to identify nematodes Anisakidae Contracaecum parasites of Phalacrocorax brasilianus, in the municipality of Soure, Ilha de Marajó, Pará. Eight specimens of P. brasilianus were acquired during the period from April 2020 to October 2021, captured and donated by riverside fishermen of the municipality of Soure. The samples were sent to the Laboratory of Histology and Animal Embryology - UFRA. The collected nematodes were processed for light microscopy, scanning electron microscopy and molecular biology, as well as counted for analyzes of ecological indices of parasitism (prevalence, average intensity and average abundance). Of the eight samples analyzed so far, 87.5% (n=7) were parasitized by Contracaecum spp., with IMI of 15.29, AM=13.38 and amplitude ranging from 1-44 parasites per host, female hosts showed higher parasite intensity with amplitude ranging from 10-44 parasites, while in males the amplitude varied between 1-7 parasites per host, in a male specimen no parasitism caused by the nematode Contracaecum was found. As for the site of infection, the ventricle was the organ most affected by parasitism caused by Contracaecum 87.5% (n=6), while one (16.67%) had parasitism in the esophagus and one (16.67%) was parasitized in the proventriculus. As for the sex of the nematodes found, 49.53% (n=53) were male and 50.47% (n=54) female. Among the recovered Contracaecum nematodes, it was possible to identify 4 distinct morphotypes.