PALEOGENESIS AND PALEO-EPIDEMIOLOGY OF PRIMATE MALARIA.

The Haemosporidia, which comprise the malaria parasites, have probably evolved from Coccidia of the intestinal epithelium of the vertebrate host by adaptation first to some tissues of the internal organs and then to life in the circulating cells of the blood.The present opinion is that, among the malaria parasites of primates, the genus Hepatocystis and the "quartan group" of plasmodia are the most ancestral, followed by the "tertian group"; from the evolutionary viewpoint the subgenus Laverania is probably the most recent.Studies recently completed and research in hand on malaria parasites of apes and monkeys, combined with the possibility of assessing the infectivity of new simian parasites to Anopheles and to man, will be of great importance for a better understanding of the probable evolution of primate malarias. The fact that several genera of the Anthropoidea evolved in an ecological area where the association with the existing insect vectors of various plasmodia was close is suggestive of Africa as the original home of primate malaria. It is probable that the disease spread up the Nile valley to the Mediterranean shores and Mesopotamia, to the Indian peninsula and to China. From these main centres malaria invaded a large part of the globe.It is also probable (though not proved) that malaria existed in the Americas before the Spanish conquest, and there is some likelihood that sea-going peoples brought it to the New World long before Columbus's voyages. Modern immunological methods applied to the study of the mummified remains of ancient inhabitants of America may help to solve this question.