Occurrence of Cryptococcus neoformans in the excreta of urban pigeons in the municipality of Redenção in Amazônia, Brazil

Currently, urban ecosystems have become increasingly conducive to pigeons, and the population of these birds has increased significantly in several parts of the world, including Brazil; this increase has become an environmental and public health problem. Materials and Methods: The objective of this research was to describe the occurrence of Cryptococcus neoformans in the excreta of pigeons in public places in the municipality of Redencao, Para, Brazil. It is a cross-sectional, quantitative, and descriptive study. Ten neighborhoods were selected, where 5 samples from each were collected, for a total of 50 units of material. Fungus was identified through suspended excreta with a sterile 0.9% sodium chloride solution, followed by seeding on Sabouraud Dextrose agar plus chloramphenicol. A direct examination of the colonies with Chinese ink was done in triplicate to observe the suggestive micromorphology of C. neoformans. A confirmatory identification test was performed by the urease production test. Results: Of the 50 samples examined, 16.0% (n = 8) were positive for C. neoformans , and in the 10 neighborhoods studied, 60.0% (n = 6) were positive for the fungus. Conclusions: The results showed that half of the positive samples were found in only two neighborhoods, suggesting that the presence of C. neoformans in a public place in the studied city can be considered a potential source of infection for humans and animals. Keywords: Pigeons; Excreta; Cryptococcus neoformans ; Environmental microbiology.