Ocorrência e caracterização morfológica de Blastocystis sp. em três espécies de aves comercializadas em mercados municipais do Rio de Janeiro

Abstract

Blastocystis hominis is one of the most prevalent parasites of the human gastrointestinal tract, but its pathogenic role still remains uncertain. Some organisms similar to B. hominis have been described in a range of non-human hosts and are denominated Blastocystis sp., but their zoonotic potential still needs clarification. The objective of this work was to investigate the occurrence of natural infection by Blastocystis sp. in three species of domesticated birds sold at cooperative markets (with individual vendor stalls) in two districts of the city of Rio de Janeiro and to characterize the morphology of these organisms found in bird droppings, to enable a precise diagnosis. A total of 214 birds were purchased: 35 ducks (Anas platyrhynchos) from market A and 38 from market B, 35 quails (Coturnix japonica) from market A and 36 from market B and 35 chicks (Gallus gallus) from market A and 35 from market B. Of the birds studied from market A, 8 chicks (22.9%), 15 quails (42.9%) and 13 ducks (37.1%) presented biological forms of Blastocystys sp. in their droppings, while at the market B, the respective figures were 15 chicks (42.9%), 2 quails (5.56%) and 21 ducks (55.3%). There was no statistically significant difference in relation to the occurrence of infection in ducks and chicks between the two markets studied, but there was between the quails at the two markets. Considering the number of infected birds at the two markets irrespective of species, the difference was statistically significant. From the observations of the stained fecal smears of the animals that were positive for Blastocystis sp., it was possible to characterize six forms of organisms, namely vacuolar, granular, ameboid, cystic, avacuolar and multivacuolar. It was also possible to characterize the reproductive forms of Blastocystis sp. as binary division, endodyogeny, budding, plamotomy and schizogeny. Even though there are no studies confirming the zoonotic and pathogenic potential of Blastocystis sp., either to human or animal hosts, we suggest that environmental contamination can be occurring at these markets, due to the poor hygienic and sanitary conditions, thus posing a risk to both the animals and the people who circulate there. The knowledge of evaluative forms that were found and characterized in this work is important to gives a precise and faithful diagnosis of Blastocystis sp. in dropping.