Anatomopathological study of parrot pufferfish Colomesus psittacus parasitized by the aspidogastrean Rohdella sp. Estudo anatomopatológico do peixe baiacu papagaio Colomesus psittacus parasitado pelo aspidogastrea Rohdella sp.

Aspidogastrea are globally-distributed parasites of the class Trematoda, which have been described as pathogens of a range of aquatic organisms, in marine and freshwater environments. The principal morphological characteristic of the group is an adhesive ventral disc, which is responsible for fixing the parasite to the host organism. In this study, 112 specimens of Colomesus psittacus from the municipality of Camet&#225;, in the state of Par&#225; (Brazil), were necropsied. Platyhelminthes of the genus Rohdella attached to the mucous membrane of the fish's intestine by the adhesive disc were observed. Fragments of parasitized tissue were fixed in Davidson solution and then processed and stained with hematoxylin-eosin. Other fragments were fixed in glutaraldehyde, processed and observed under a scanning electron microscope. The prevalence of the parasite was 76.4%, mean intensity of infection was 8.0 and mean abundance was 6.2. The parasitism provoked chronic enteritis with diffused inflammatory infiltration. The adherence of the parasite to the mucous membrane of the intestine resulted in strangulation and hyperplasia of the region, as well as causing hypertrophy of the muscle of the mucous membrane. The present study describes the anatomopathological and ultrastructural aspects of the parasitism of the intestine of C. psittacus by Rohdella sp.<br>Os Aspidogastreas s&#227;o parasitos da classe Trematoda, distribu&#237;dos globalmente e t&#234;m sido descritos como pat&#243;genos em uma gama de organismos aqu&#225;ticos de ambientes marinhos e de &#225;gua doce. A principal caracter&#237;stica morfol&#243;gica do grupo &#233; um disco adesivo na regi&#227;o ventral respons&#225;vel pela fixa&#231;&#227;o do parasito no organismo hospedeiro. Neste estudo, 112 esp&#233;cimes de Colomesus psittacus provenientes do munic&#237;pio de Camet&#225;, no estado do Par&#225; (Brasil), foram necropsiados. Foram observados platelmintos do g&#234;nero Rohdella aderidos &#224; mucosa intestinal atrav&#233;s do disco adesivo. Fragmentos de tecido com parasito foram fixados em solu&#231;&#227;o de Davidson e processados e corados em Hematoxilina-Eosina. Outros fragmentos foram fixados em glutaralde&#237;do, processados e observados em microscopia eletr&#244;nica de varredura. A preval&#234;ncia parasit&#225;ria foi de 76, 4%, intensidade m&#233;dia de infec&#231;&#227;o de 8,0 e abund&#226;ncia m&#233;dia de 6,2. O parasitismo ocasionou uma enterite cr&#244;nica com difuso infiltrado inflamat&#243;rio. A fixa&#231;&#227;o do parasito na mucosa intestinal provocou estrangulamento e hiperplasia da regi&#227;o, bem como hipertrofia da muscular da mucosa. O presente trabalho descreve os aspectos anatomopatol&#243;gicos e ultra-estruturais da a&#231;&#227;o parasit&#225;ria por Rohdella sp. no trato intestinal de C. psittacus.