Trichurid nematodes in ring-necked pheasants from backyard flocks of the State of Rio de Janeiro, Brazil: frequency and pathology

RESUMO

The present investigation is related to the frequency of infection and to the gross and microscopic lesions associated to the presence of trichurid worms in 50 ring-necked pheasants (Phasianus colchicus) from backyard flocks in the state of Rio de Janeiro, Brazil. In the investigated birds, the overall infection rate was of 74 percent, with the presence of Eucoleus perforans with 72 percent of prevalence and 21.2 of mean intensity, in the esophageal and crop mucosa and rarely in the junction of the proventriculus and esophagus, E. annulatus with 2 percent and 3 in the crop mucosa, Capillaria phasianina, with 12 percent and 4.3 in the cecum and small intestine and Baruscapillaria obsignata, for the first time referred in this host, with 2 percent and 1 in the small intestine. Clinical signs were absent. The gross lesions observed in the crop and esophagus of 14 (38.9 percent) pheasants parasitized with E. perforans were thickening, small nodules, congestion, and petechial haemorrhages in the mucosa. These birds presented a mean infection of 37.5 and a range of infection of 10-82. The microscopic lesions revealed chronic esophagitis with diffuse inflammatory process in the lamina propria characterized mostly by a mononuclear cell infiltrate and also with the presence of granulocytes. In the case of the parasitism of pheasants with C. phasianina, the gross lesions were absent; microscopic lesions were characterized by chronic typhlitis with mononuclear infiltrate. Gross and microscopic lesions were absent in the pheasants parasitized with E. annulatus and B. obsignata.