Humans have 342 species of helminth parasites, and 70 species of protozoan parasites. A hookworm is a type of parasitic worm (helminth). It is a nematode (roundworm) and a common intestinal parasite or helminth, especially in humans. It acts as an intermediate host for the helminth parasite by harbouring the larval stages. Raillietina is a genus of tapeworms that includes helminth parasites of vertebrates, mostly of birds. Several species of feather mites, helminth and blood parasites have been described from the species. An infection by a helminth is known as helminthiasis, helminth infection, or intestinal worm infection. Nevertheless, there was widespread presence of several helminth types (intestinal worms) that caused dysentery. In humans, T helper cells and eosinophils respond to helminth infestation. ILC2s play the crucial role of secreting type 2 cytokines in response to helminth infection. Trichuriasis is caused by a parasitic worm also known as a helminth called "Trichuris trichiura". The infection can lead to tissue damage, due to migration of the helminth. It belongs to the group of helminth infections. It is a type of helminth infection.