First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil

Our plain-English summary of First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil, by D.T. Takahara, S. Lazéra Mdos, B. Wanke, et al (Revista Do Instituto de Medicina Tropical de São Paulo, 2013).

The study

• Authors: D.T. Takahara, S. Lazéra Mdos, B. Wanke, L. Trilles, V. Dutra, D.A. Paula, L. Nakazato, M.C. Anzai, D.P. Leite Júnior, C.R. Paula, R.C. Hahn
• Journal: Revista Do Instituto de Medicina Tropical de São Paulo
• Published: 2013;55(6):371-6
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

In plain English

This study looked for the fungus Cryptococcus neoformans, a cause of the infection cryptococcosis, in dried pigeon droppings in the Cuiabá area of Mato Grosso, Brazil. It is not a study of asbestos. Asbestos is mentioned only as the covering of four open-area sampling sites, and no asbestos was measured. Between July and December 2010 the authors visited 63 sites, found pigeon droppings at 49, and collected 122 samples. The sites were squares, churches, educational institutions, health units, the asbestos-covered open areas, residences, a factory and a prison. The fungus was identified with laboratory tests and confirmed by PCR, a genetic test. It was found in 8 of 122 samples (6.6%) from 6 of 49 sites (12.2%): one church tower, one educational institution and four of 23 residences. None of the 11 samples from the asbestos-covered open areas was positive. The authors concluded that the findings revealed a risk of exposure for both immunosuppressed and immunocompetent people living or spending time in these places.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Environmental survey: sampling of dried pigeon excreta at public and residential sites, with laboratory and PCR identification of Cryptococcus neoformans
• Who was studied: 122 samples of dried pigeon excreta from 49 sites (out of 63 visited) in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil, collected July to December 2010. Sites with excreta were 5 public squares, 4 churches, 3 educational institutions, 8 public health units, 4 open areas covered with asbestos, 23 residences, 1 factory and 1 prison.
• Exposure: Presence of the fungus Cryptococcus neoformans in pigeon excreta. Asbestos appears only as the covering of four open-area sites; the study did not measure asbestos or study asbestos-related disease.
• Main results:
  • Overall, C. neoformans was isolated from 8 (6.6%) of 122 samples, from 6 (12.2%) of 49 sites.
  • Churches: C. neoformans was found in 1 of the 4 churches with excreta, in the tower; two samples from that church were positive.
  • Educational institutions: C. neoformans was found in 1 of the 13 samples analyzed.
  • Residences: C. neoformans was found at 4 of the 23 residences evaluated, in 5 positive samples (44 residential samples in total per the table).
  • Open areas with asbestos covering: 4 sites with excreta, 11 samples, 0 positive.
  • Public squares: no Cryptococcus was isolated. Health units, the factory and the prison also had no positive samples (per the table).
  • All isolated colonies were confirmed as C. neoformans by PCR with specific primers.
• The authors' conclusion: The authors concluded that C. neoformans was mainly isolated from protected places (an educational institution, a church and four residences). They said this revealed a risk of exposure for immunosuppressed and even immunocompetent people living or carrying out daily activities in these places. They suggested that sunlight and Cuiabá's climate may be critical for the survival of the fungus in open areas.
• Limitations the authors state:
  • Only pigeon excreta was sampled; soil samples were not included.
  • The molecular types of the isolates were not determined.
  • Frequent cleaning at several public sites meant the amount of excreta varied, and excreta was not found at all selected sites despite pigeons being present.

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