Blood Parasites of Southeast Asian Primitive Primates

Abstract

Blood film examination records for 450 Southeast Asian primitive primates (prosimians) are summarized and discussed. These data suggest that the tupaioids and lorisoids of this region probably do not harbor malaria parasites and need not be considered in the study of malaria as a zoonosis. On present evidence it appears that the lemurs of Madagascar are the only prosimians harboring malaria parasites. Several trypanosomes and filariids of Malaysian prosimians are briefly noted. It is now recognized that malaria caused by certain species of plasmodia of nonhuman primates probably must be classified as a zoonosis (Contacos and Coatney, 1963). The definitive link-mosquito transmission from infected monkey to man in nature-has not yet been demonstrated, but much evidence has accumulated to suggest that natural transmission to man may occur in certain places, although probably rarely (Wharton and Warren, 1963). One of the present problems in primate malaria research is the inadequacy of our knowledge of the number of species of plasmodia present in these hosts, the host distribution of these parasites, their geographic distribution, and their prevalence in each host species in nature. Several species of primate plasmodia probably remain to be recognized. In 3 years of intensive study in Malaya, Eyles and his colleagues uncovered three previously undescribed species (Eyles, 1963). Others may yet be recognized, in southern Asia and elsewhere, and it is certain that such little-known species as Plasmodium Received for publication 13 December 1963. * This study was supported in part by Contract No. DA-49-193-MD-2291 from the Office of the Surgeon General, Department of the Army, with sponsorship by the Commission on Parasitic Diseases, U. S. Armed Forces Epidemiological Board; in part by U. S. Public Health Service Grant GM-11329-03 from the ICMRT Program, Office of International Research, National Institutes of Health. t Current address: Medical Zoology Laboratory, Institute for Medical Research, Kuala Lumpur, Malaysia. simium da Fonseca, 1951 and P. hylobati Rodhain, 1941 must be more fully characterized than they have been in the past. In this paper data resulting from blood film examinations between 1954 and 1963 of 450 Southeast Asian primitive primates (prosimians) are reviewed and discussed. METHODS AND FINDINGS The data presented in Table I have been compiled from several sources. Negative records for 19 Tupaia belangeri of Loei Province, Thailand were reported by Coatney et al. (1960). I have recorded negative findings elsewhere for 14 Tupaia glis collected on Pulau Tioman, an island off the coast of Pahang State, Malaya (Dunn, 1964). There do not appear to be other published records for blood film findings in Southeast Asian prosimians. The records in Table I for 50 Tupaia glis and 48 Nycticebus coucang from the vicinity of Kuantan, Pahang State, examined between 19551961, were extracted from the files of the Malaria and Filariasis Division of the Institute for Medical Research with the assistance of Mr. Yap Loy Fong. Records for tree shrews and lorises collected in Selangor State, Malaya between 1954-1961 were also obtained from these files. I am indebted to Prof. A. A. Sandosham, Senior Malaria and Filariasis Research Officer, for permission to summarize these records. Other data, including all for North Borneo, for 39 tree shrews and lorises collected in Selangor in 1962-1963, and for other Malayan localities in 1962-1963, are from the writer's records. All Malayan and Bornean records are based on thorough examination of two thick and two thin blood films by one of several experienced laboratory assistants.