Parasitic infections, sexually transmitted

Trichomonas vaginalis is a common sexually transmitted parasite. Infection rates vary from 10% to 50% with the highest reported rates found in the USA. Infections are usually asymptomatic or mild although symptomatic infection is most common in women. Trichomonads are all anaerobes and contain hydrogenosomes. This organelle is found in very few other anaerobic eukaryotes and is often... 

Viruses have been implicated in the development of at least two cancers. Infection with the human papilloma virus is a major risk factor for cervical cancer, and like any sexually transmitted disease, the cancer is more common amongst those who have had numerous partners and is almost unknown in nuns. But the most well-established link is between Burkitt s lymphoma and the Epstein-Barr virus (one of the herpes viruses) in African countries. In developed countries, this virus causes glandular fever (infectious mononucleosis), and the different progress of the disease in Africans is apparently due to an immune system that is usually suppressed through a long-term assault by malaria parasites like Plasmodium falciparum. 

Malaria is transmitted by the bite of an infected Anopheles mosquito that introduces the sporozoites (tissue parasites) of the plasmodia P. falciparum, P. vivax, P. malariae, and P ovale) into the bloodstream. The asexual reproduction stage develops in humans, whereas the sexual stage occurs in the mosquito. The sporozoites invade parenchymal hepatocytes, multiply in stages referred to as exoery-throcytic stages, and become hepatic vegetative forms or schizonts. Schizonts rupture to release daughter cells, or merozoites, that then infect erythrocytes. 

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