Hookworm infection is an infection by a type of intestinal parasite known as a hookworm. Water pollution results in typhoid, dysentery, hepatitis, trachoma, hookworm, and diarrhea. Scientists are also searching for a vaccine against helminths, such as a hookworm vaccine. It is a parasitic nematode worm and commonly known as the Old World hookworm. Co-infection with hookworm and "Plasmodium falciparum" is common in Africa. Hookworm infections in humans include ancylostomiasis and necatoriasis. Many of the workers and their families suffered from yaws, hookworm, and malaria. Other important issues related to the treatment of hookworm are reinfection and drug resistance. This infection is due to larvae from the "A. braziliense" hookworm. Albendazole and mebendazole have been the treatments administered to entire populations to control hookworm infection. In the early 20th century, tetrachloroethene was used for the treatment of hookworm infestation. Adult hookworm antigens have also been identified as potential candidates for vaccines. Specifically it is used for ascariasis and hookworm infections. For example, the hookworm species "Necator americanus". This substantiates prior claims that albendazole is much more effective than mebendazole for hookworm infections.