A broad range of parasites were present in ancient Egypt and Nubia, with 15 different species, including ectoparasites, helminths, and protozoa. Some are spread directly from one person to another (such as pinworm and head lice), some pass through animals as part of their life cycle (such as Taenia tapeworms, fish tapeworm, and trichinella), while others require biting insect vectors to spread them (such as malaria, leishmaniasis, and filariasis). Around 40% of ancient Nubians had head lice, 10% of Nubians were infected by visceral leishmaniasis, 22% of Egyptian mummies were positive for malaria, and 17% were positive for schistosomiasis. As malaria and schistosomiasis cause chronic anaemia and fatigue during physical work, they must have been responsible for a considerable drain upon the capabilities of the workforce in these civilizations along the Nile.