Avaliação da presença de Cryptococcus ssp. no Bosque Marechal Cândido Rondon e na Praça Marechal Floriano Peixoto no centro de Londrina-PR

Abstract

Illnesses related to urban pigeons make this bird a subject to environmental health, as they host many pathogenic microorganisms that are biological risk factors for human health. Among these microorganisms there is a causative fungus of cryptococcosis, a disease that affects the lungs and central nervous system and can lead to death of people with more vulnerable health. It is believed that this infection is acquired from the environment by inhaling the fungal bioaerosols Cryptococcus genus, commonly found in pigeon droppings. The overpopulation of pigeons in central Londrina raises the hypothesis that there is a potential risk of contamination of people transiting near Bosque Marechal Candido Rondon and Praça Marechal Floriano Peixoto, which are the sites most affected by pigeons, as well as of large people circulation. In order to assess the presence of the fungus Cryptococcus ssp. in these sites, three sampling campaigns were carried out in March, August and September of 2020, with two daily samplings, one in the morning and other in the afternoon. Bioaerosols were collected by spontaneous sedimentation technique in Petri plates containing a selective medium for fungi. The collections took place at five points in Bosque and three points in Praça, which were considered as being places with a constant flow of people. After incubation of the collected fungi inside bacteriological oven for 96 hours at 30 ± 1 ° C, we performed the counting of the Forming Units Colonies (CFU). In addition, we carried out identification and isolation of colonies presenting yeast-like and white/beige characteristics, as well as confirmation of the Cryptococcus genus through microscopic visualization of the fungi isolated in Tinta Nanquim suspension. The average concentration of CFU.m-3 fungal found in samples collected in the morning was 633, while the average in the afternoon samples was 1.143 CFU.m-3. The weather conditions directly interfere in the results, suggesting a relationship between the ambient temperature at the time of collection and the average concentration of CFU.m-3. The average percentage of yeast-like CFU found throughout the samples was 11.3%, thus being minority compared to filamentous fungi. Of the ten isolated yeast-like colonies that had the characteristics of the fungus in the study, 80% were classified as belonging to the genus Cryptococcus. The results show that the two sampling sites presented bioaerosols of the Cryptococcus genus that may be inhaled by people who circulate in these environments.