Caracterização morfológica e histopatológica de microparasitos em metynnis hypsauchen, metynnis lippincotianus e Serrasalmus rhombeus (characiforme:Serrasalmidae), oriundos dos municípios de Santa Izabel e Ipixuna do Pará, Pará, Brasil.

Abstract

Fish are the hosts most parasitized in the world, an aspect enhanced by the aquatic life habit wich is ideal for the propagation of several species of parasites. Given the richness of Amazonian fish, parasitological studies are essential to characterize the degree of pathogenicity in the host. In this context, the goal of this work was to describe morphological aspects of microparasites from Metynnis hypsauchen, Metynnis lippincotianus and Serrasalmus rhombeus, captured in the Caraparu river, located in Santa Izabel do Pará and Capim river, i located in Ipixuna do Pará. The samples were transported alive to the Carlos Azevedo Research Laboratory of the Federal Rural University of Amazon (UFRA) campus Belém, where they were anesthetized, sacrificed and necropsied. Parasitological searches were supported by a stereomicroscope, for observation of cysts and/or tissue with evidence of parasitism, confirmed by freshly prepared slides viewed under an optical microscope. The samples were fixed and processed for histology and scanning electron microscopy. In the morphological analysis, mature spores of parasites of the Myxozoa class were observed, with morphology inherent to the genus Myxobolus in the kidneys of M. hypsauchen and in several organs of M. lippincotianus. In this last host species, parasites of the genus Henneguya were also observed in the gills, forming intralamellars cysts. In S. rhombeus, spherical oocysts of the Calyptospora coccidia were found in the hepatic parenchyma. The highest parasite prevalence in both collection sites corresponded to the dry period in the Amazon, being continuous until the transitional months. Studies like this one are important for the knowledge of the parasites that affect fish the serrasalmids, in which present myxozoans with morphotypes different from those described in fish from the Amazon region.