Medical protozoa Pathogenic Opportunistic parasite Not normally pathogens Become pathogenic due to impairment of host resistance Clinical importance of the AlDS epidemic Opportunistic parasites An infection by a microorganism that normally does not cause disease but becomes pathogenic when the body's immune system is impaired and unable to fight off infectionMedical Protozoa ▪ Pathogenic ▪ Opportunistic parasite ➢ Not normally pathogens ➢ Become pathogenic due to impairment of host resistance ➢ Clinical importance of the AIDS epidemic ▪ Opportunistic parasites ▪ An infection by a microorganism that normally does not cause disease but becomes pathogenic when the body's immune system is impaired and unable to fight off infection