The sickle-cell trait is believed to be protective against malaria. Thus, sickle-cell disease is at its highest frequency in West Africans and people of West African descent. But this trait is not common in other regions of Africa, where malaria is not as prevalent. Therefore, it is not an “African” disease. Sickle cell also appears in other regions of the globe, in other human populations, including populations in the Mediterranean Basin, the Arabian Peninsula, and on the Indian subcontinent, where these populations also saw this adaptation to resist malaria.