“M” is for Malaria. Malaria was arguably the most significant disease in the history of South Carolina. It is a parasitic infection caused by protozoa known as plasmodia and transmitted by anopheline mosquitoes. Two types of malaria dominated in South Carolina. Both are highly debilitating diseases that produce lethargy and vulnerability to other infections. The first, and milder form, probably came with European settlers in the 1670s. The deadlier version came with the importation of large numbers of enslaved persons from Africa in the 1680s and after. By the early eighteenth century, malaria was endemic in the lowcountry. It would later become a major health problem in much of the rest of the state. By the early 1950s, malaria had virtually disappeared from the state for reasons that still are not entirely understood.