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

Abstract

Introduction: 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 Redenção, Pará, 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.