Colonic epithelial nodular hyperplasia associated with strongyloidiasis in cats in the Amazon region, Pará State, Brazil

Strongyloides spp. are intestinal parasites that affect several animal species. Four species of the genus have been reported in domestic cats: S. felis, S. planiceps, S.stercoralis and S. tumefaciens . Reports describing infection by these nematodes in domestic cats in Brazil are scarce. This study aimed to describe the pathological features of Strongyloides spp. parasitism in two cats in the Amazon region, state of Pará, Brazil. During the necropsy of the two cats, numerous whitish nodules approximately 0.2cm in diameter were observed in the wall of the large intestine. The nodules were conspicuous in the colonic mucosa and exhibited a punctate aperture facing the center of the lumen. Microscopically, these nodules were formed by projections of the mucosal epithelium into the submucosa, which formed tubules lined with a single layer of columnar epithelium, with high cellularity and rare goblet cells, characterizing epithelial hyperplasia of the crypts. Adult nematodes and eggs observed in the lumen of the tubules were morphologically compatible with Strongyloides spp. Numerous larvae were also observed in the interstitium adjacent to the nodule. A mild lymphocytic infiltrate was observed neighboring the hyperplastic nodules. The histological changes are consistent with those described for S. tumefaciens infection. RESUMO: Strongyloides spp. são helmintos que podem parasitar o intestino de diversas espécies animais. Quatro espécies desse gênero têm sido descritas em felinos domésticos: S. felis, S. planiceps, S. stercoralis e S. tumefaciens. Trabalhos sobre o parasitismo por estrongiloides em gatos domésticos no Brasil são escassos. O objetivo deste trabalho é descrever os aspectos patológicos do parasitismo por Strongyloides spp. em dois gatos da região amazônica, no estado do Pará. Estes apresentavam numerosos nódulos esbranquiçados no intestino grosso, medindo cerca de 0,2 centímetros de diâmetro, que na microscopia eram constituídos por projeções do epitélio hiperplásico da mucosa para submucosa, formando túbulos contendo várias fêmeas adultas, ovos e larvas com morfologia compatível com a de Strongyloides spp. e margeados por larvas e remanescentes do aglomerado linfoide. As alterações histológicas foram compatíveis com as descritas no parasitismo por S. tumefaciens.