Prevalence of Malaria in Panamanian Primates

Abstract

Over a 35-year period, 1,994 Panamian primates representing seven species have been examined for malaria at the Gorgas Memorial Laboratory. Plasmodium brasilianum was the only species found. The prevalence rates for the various species were: Ateles geoffroyi (30.3%), A. fusciceps (10.6%), Alouatta villosa (4.0%), and Cebus capucinus (2.2%). No infections were found in Saimiri iierstedii, Aotus trivirgatus, and Saguinus geoffroyi. Malaria in primates has interested workers at Gorgas Memorial Laboratory for the past 35 years. Clark (1930, 1931) surveyed Panamanian primates for malaria and other parasites. Clark and Dunn (1931) reported an attempt to transfer the malaria parasite of Ateles geoffroyi to man. Taliaferro and Taliaferro (1934a, b, c, 1944) and Taliaferro and Kluver (1940a, b) studied Plasmodium brasilianum in Panamanian primates. Taliaferro and Taliaferro (1934d) and Taliaferro and Cannon (1934) attempted the transmission of P. falciparum to the Panamanian howler monkey (Alouatta villosa). Since these early reports, much additional information has been obtained. Nearly 2,000 Panamanian primates have been examined on receipt at the laboratory from 1931 to 1957 and during the past year. The purpose of this paper is to summarize the information on the prevalence of malaria in these animals. MATERIALS AND METHODS Records kept at the laboratory include information on species, geographic origin, age, and sex of the primate. Primates examined were Ateles fusciceps (black spider monkey), Ateles geoffroyi (red spider monkey), Cebus capucinus (whiteface monkey), Alouatta villosa (black howler monkey), Saimiri oerstedii (squirrel monkey), Aotus trivirgatus (night monkey), and Saguinus geoffroyi (titi marmoset). Weight was the principal factor used in separating infants from juveniles. One thousand grams was used as a separation weight for Ateles and Alouatta, 750 g for Cebus, 300 g for Saimiri and Aotus, and 200 g for Saguinus. Juveniles were separated from adults by lack of sexual maturity. Received for publication 27 April 1966. * During the past year, these studies have been supported in part by the United States Army Medical Research and Development Command, grant DA-MD-49-193-65-G-165. Until last year, all primates entering Gorgas Memorial Laboratory were examined on at least 5 consecutive weekdays for malaria parasites and monthly thereafter. In most cases, the initial period of five daily examinations now is followed by weekly examinations. Thick blood films are made, stained with Giemsa, and examined microscopically.