Plasmodium vivax is a protozoal parasite and a human pathogen. Trichomonas vaginalis is an anaerobic, flagellated protozoan parasite and the causative agent of trichomoniasis. The bacterium is an obligate intracellular pathogenic parasite. Hookworm infection is an infection by a type of intestinal parasite known as a hookworm. This was the first protozoan parasite of humans to be seen under a microscope. Wasps infected with the male parasite die. Giardiasis is a disease of the small intestine caused by a protist parasite "Giardia lamblia". Chimps and humans share only 50% of their parasite and microbe species. The apicomplexans include "Plasmodium", the malaria parasite. Ivermectin is a medication used to treat many types of parasite infestations. Human infections by this parasite are common at Lake Victoria. The bird is a host of the acanthocephalan intestinal parasite "Apororhynchus silesiacus". In parasitology superinfection refers to reinfection of same species of parasite. Some species secrete gels that are effective in parasite control. Parasitism for the individual (the brood parasite) also has significant drawbacks.