Plasmodium malariae is a parasitic protozoan that causes malaria in humans. Malaria is caused by a protozoan called Plasmodium falciparum. Humans have 342 species of helminth parasites, and 70 species of protozoan parasites. A preclinical study showed that blocking parasite MIF improves outcome in severe protozoan infections. IgE is utilized during immune defense against certain protozoan parasites such as "Plasmodium falciparum". "Entamoeba histolytica" is a unicellular parasitic protozoan that infects the lower gastrointestinal tract of humans. It was Golgi who helped him prove that malarial parasite was a microscopic protozoan. Leishmaniasis is a disease caused by protozoan parasites of the genus "Leishmania". Praziquantel is effective against various helminthic and protozoan infections. The protozoan and helminth pathogens can be removed by the mechanism of sedimentation. Giardiasis is a disease caused by infection with the protozoan "Giardia lamblia". Giardiasis is caused by the protozoan "Giardia duodenalis". Antigenic variation is employed by a number of different protozoan parasites. The protozoan "Ophryocystis elektroscirrha" is another parasite of the monarch. Trichomoniasis is transmitted by a parasitic protozoan and is the most common non-viral STI.