Clues to the presence of pathogenic fungi in certain environments

Abstract

The presence of various pathogenic fungi in rather unsuspected hosts and environments has always attracted the attention of the scientific community. Reports on the putative role of animals in fungal infections of humans bear important consequences on public health as well as on the understanding of fungal ecology. Fungi are ubiquitous in nature and their great capacity for adaptation allows them to survive and indeed, to thrive, in plants, trees and other natural substrata. Nonetheless, we are just beginning to learn the significance that these diverse fungal habitats have on the increasing number of immunosuppressed individuals. The accidental or permanent presence of fungi in animals, plants, soils and watercourses should not be taken too lightly because they constitute the source where potential pathogens will be contracted. If those fungal habitats that carry the largest risks of exposure could be defined, if seasonal variations in the production of infectious propagules could be determined, and if their mode of transmission were to be assessed, it would be possible to develop protective measures in order to avoid human infection. Additionally, unsuspected avenues for the exploration of fungal survival strategies would be opened, thus enhancing our capacity to react properly to their advancing limits. This paper explores several ecological connections between human pathogenic fungi and certain animals, trees, waterways and degraded organic materials. The occurrence of such connections in highly endemic areas will hopefully furnish more precise clues to fungal habitats and allow the design of control programs aimed at avoiding human infection.

Paracoccidioides brasiliensis: phylogenetic and ecological aspects

“…brasiliensis isolates obtained from armadillos present a significant variability with regard to virulence, antigen and molecular (RAPD and sequencing of rDNA regions and gp43 gene) profiles [60][61][62][63]. This variability does not seem to be related to its hosts, since P. brasiliensis isolates from nine-banded armadillo are indistinguishable from clinical ones, indicating that the same ''ecopathogenotypes'' infect both animals and human [49,54,64]. By having a low body temperature, ranging from 32.7 to 35.3°C [65], a weak immunological system [66] and constant contact with P. brasiliensis in soil, armadillos may infect and acquire the pathogen repeatedly.…”

Estudo dos nichos ecológicos de leveduras patogênicas das espécies Cryptococcus neoformans e Cryptococcus gattii na cidade de Londrina, PR

“…C. gattii encontra-se presente em folhas, partes ocas do tronco e madeira em decomposição de árvores pertencentes às espécies australianas Eucalyptus camaldulensis e E. tereticornis, além de árvores nativas de espécies existentes em regiões dos continentes de clima tropical e subtropical (SORREL, 2001;KHAN, 2003). As diferentes características epidemiológicas dos fungos das espécies patogênicas do gênero Cryptococcus determinam seja necessário o estudo do habitat, das variações sazonais em relação à produção de propágulos infecciosos e das vias de transmissão, desse modo medidas de profilaxia e controle da infecção poderão ser desenvolvidas para humanos e animais (RESTREPO et al, 2000).…”

Resistance of melanized yeast cells of Paracoccidioides brasiliensis to antimicrobial oxidants and inhibition of phagocytosis using carbohydrates and monoclonal antibody to CD18

“…PCM is a chronic, granulomatous disease, geographically limited to Latin America. The disease is acquired by inhalation of fungal conidia, presumably from the soil and likely on routes of armadillo roving (San-Blas et al 1993, Restrepo et al 2000, Bagagli et al 2006.…”