The palaeogeography of mosquito-borne disease

Abstract

Malaria parasites Plasmodiidae and their evolutionary precursors (Haemoproteidae arc found in reptiles, birds and mammals. The distribution of reptile plasmodiids relative to the former Panamanian portal suggests an origin in the very early Tertiary at the latest. Fossil vectors are known from the Lower Cretaceous. Avian plasmodiids, unlike those of reptiles, are no more successful than their haemoproteids and are presumably of more recent origin. Their wide host range and indifferent taxonomy admit of little evolutionary speculation. Mammal plasmodiids are confined to Dermoptera, artiodactyls, bats, rodents and primates. Haemoproteids are found in the last four and in elephant shrews, suggesting an origin in early Tertiary Archonta and allied arboreal ancestors of rodents and artiodactvls. The latter have acquired different vectors [Anopheles sen. su slriclo) from those of the others which, so far as known, are confined to series Neomyzomyia of subgenus C. ellia, a group of African origin. Primate malarias are believed to have spread from Africa into Asia, those ol other orders to have evolved in situ. Secondary acquisition is suspected in murids. The African plasmodiid fauna is clearly a relict one. Human and other primate malarias may have been acquired as both zoonoses and anthroponoses. The association between human malarias and haemoglobinopathies affords clues to the palaeogeography of African man.