Domestic Birds as Source of Cryptococcus deuterogattii (AFLP6/VGII): Potential Risk for Cryptococcosis

Abstract

Cryptococcosis is an infection caused by encapsulated basidiomycetous yeasts belonging to the Cryptococcus neoformans/Cryptococcus gattii species complexes. It is acquired through inhalation of infectious propagules, often resulting in meningitis and meningoencephalitis. The ecological niche of these agents is a wide variety of trees species, as well as pigeon, parrot and passerine excreta. The objective of this study was to isolate Cryptococcus yeasts from excreta of commercially traded parrots and passerines. The 237 samples were collected between October 2018 and April 2019 and processed using conventional methodologies. Nineteen colonies with a dark brown phenotype, caused by phenol oxidase activity, were isolated, suggesting the presence of pathogenic Cryptococcus yeasts. All isolates tested positive for urease activity. URA5-RFLP fingerprinting identified 14 isolates (68.4%) as C. neoformans (genotype AFLP1/VNI) and 5 (26.3%) as C. deuterogattii (genotype AFLP6/VGII). Multi-locus sequence typing was applied to investigate the relatedness of the C. deuterogattii isolates with those collected globally, showing that those originating from bird-excreta were genetically indistinguishable from some clinical isolates collected during the past two decades.

Epidemiology of Nosocomial Infections

“…Ticks that can complete their lifecycle indoors (such as Rhipicephalus sanguineus, the brown dog tick) can become a serious problem. Vertebrate vectors include rodents and pigeons (clinically significant Cryptococcus species can be isolated from pigeon droppings) (Siqueira et al, 2022).…”

Emerging Animal-Associated Fungal Diseases

“…However, species belonging to both the C. neoformans and C. gattii species complexes shift to an infective yeast form once they go through the respiratory system of mammals. Numerous cases, outbreaks and epidemics of cryptococcosis by the two species complexes have been documented in farmed and companion animals: birds, cattle, horses, cats and dogs, among others [ 92 , 93 , 94 ]. The risk of human cryptococcosis by these infected animals should not be neglected given that they are part of our daily life and have a high potential to contaminate the environment.…”

Fungal isolation and identification from parrot excreta in northeast Iran: A threat to human health

“…These infections can be developed in the birds themselves through environmental contamination of their habitats (Fraga et al., 2011 ; Simi et al., 2019 ). Bird faeces, including parrot droppings, can be a potential carrier for spreading pathogenic fungi such as Cryptococcus neoformans into the environment (Siqueira et al., 2022 ).…”