Protozoa hosts lead to virulence

Infections by protozoa in immunocompromised hosts.

Protozoa are among the most important pathogens that can cause infection in immunocompromised patients. They infect particularly individuals with impaired cell immunity, such as those with hematologic neoplasias, those submitted to transplant of solid organs, those under high-dose corticosteroid therapy, and carriers of the human immunodeficiency virus. Among the protozoa that most commonly cau...

Epigenetic Regulation of Virulence Gene Expression in Parasitic Protozoa

Protozoan parasites colonize numerous metazoan hosts and insect vectors through their life cycles, with the need to respond quickly and reversibly while encountering diverse and often hostile ecological niches. To succeed, parasites must also persist within individuals until transmission between hosts is achieved. Several parasitic protozoa cause a huge burden of disease in humans and livestock...

Immunity to Protozoa

Parasites with complex life cycles often stimulate both antibodyand cell-mediated defence mechanisms, whose effectiveness depends on the particular parasite and the stage of infection. Malaria, which is caused by different species of plasmodia, ranks amongst the most common and important parasitic diseases. Infection of humans is initiatedby thebite of an infectedmosquito, resulting in the inje...

Virulence Is Positively Selected by Transmission Success between Mammalian Hosts

Virulence, defined as damage to the host, is a trait of pathogens that evolutionary theory suggests benefits the pathogen in the "struggle for existence". Pathogens employ virulence mechanisms that contribute to disease. Central to the evolution of virulence of the infectious agents causing an array of bacterial disease is the evolutionary acquisition of type III secretion, a macromolecular com...

Immunity to protozoa and worms