Description | A symbiote which is capable of causing harm to a host, but only when the host is significantly damaged, weakened, stressed or found in an unnatural context. Normally, an opportunistic pathogen will have a commensalistic or mutualistic relationship with the host, but sometimes will have no significant relationship with the host in its normal state of health. Normal non-pathogenic host flora which reside in a particular location (mouth, stomach, intestine) may cause severe disease if they gain access to other tissues, possibly through lesions caused by other pathogens or diseases. |