Determinants of virulence in the pathogenic fungi

To understand the origin of virulence among pathogenic fungus is important to consider both the host the ecologic riche of the microbe involved. Host-associated pathogenic fungi (eg commensals such as Candida albicans) generally cause disease only in situtations where there is a disruption of the host-microbe relationship. On the other hand, pathogenic fungi acquired from the environment typically cause disease in impaired hosts, after exposure to large infective inocula, and/or when a more virulent variant emerges. Animal and plant pathogenic fungi acquired from the environment probably face similar selection pressures from physical conditions, microbial competition and predators such as amoebae. For some human pathogenic fungi the determinants of virulence (virulence factors) appear to have been selected for environmental survival and function in mammalian virulence more by accident or happenstance, than design. Given that many emerging infectious diseases reflect interspecies and cross-kingdom jumps in pathogenicity an enhanced understanding of the determinants of virulence in animal and plant pathogenic fungi could help anticipate and prepare for future microbial threats.