Periódicos Brasileiros em Medicina Veterinária e Zootecnia

Infecção natural por Histomonas meleagridis em pavões-indianos (Pavo cristatus)

Costa, Ricardo Almeida daPereira, Ana Paula MauriqueSilveira, Caroline da SilvaAnjos, Bruno Leite

Background: Histomonas, also known as blackhead, is a protozoan disease caused by Histomonas meleagridis (phylum Parabasalia, class Tritrichomonadea, order Tritrichomonadida, family Dientamoebidae/Protrichomonadinae) and, characterized by enteric and hepatic lesions in several species of domestic and wild gallinaceous. Among the most affected species, turkeys are those with greater morbidity and mortality. Blackhead is the second most important disease caused by protozoa in domestic poultry, affecting especially young birds and causing severe economic losses, with decrease in production, lack of uniformity of lots and costs with treatment and control. Its occurrence must be monitored, especially in large poultry exporting countries, such as Brazil. The aim of this study is to report an outbreak of histomoniasis in Indian peacocks.Case: A peacocks group created together with chickens showed clinical signs characterized by apathy, head down and bruised head, eyes closed, anorexia, yellow or pale stools and death. At necropsy, the cecum showed intense thickening of the wall with irregularity in the serous layer and abundant deposit of friable material, amorphous, yellowish color with areas reddish in the lumen with large number of filiform white parasites from 1 to 1.5 cm in length, morphologically compatible with Heterakis gallinarum. The liver showed large and circular, multifocal, whitish areas that extended towards the parenchyma. Histologically, was observed marked transmural typhlitis, severe proliferation of fibroblasts with multifocal neovascularization, histiocytic infiltrate, giant cell enlargement, bacterial myriads, presence of eosinophilic circulars trophozoites, with 6-20 μm in diameter, morphologically compatible with Histomonas meleagridis. These structures were positive in PAS staining.[...](AU)

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