Susceptibility of Owl Monkeys to Plasmodium falciparum Infection in Relation to Location of Origin, Phenotype, and Karyotype

The relationship among geographic origin, phenotype, karyotype, and susceptibility of owl monkeys to 2 strains of Plasmodium falciparum was investigated. Owl monkeys from Columbia and Panama were both susceptible to fatal infections with the Asian FVO (Vietnam-Oak Knoll) strain of P. falciparum. However, when inoculated with the African FUP (Uganda-Palo Alto) strain, most Colombian owl monkeys developed fatal or potentially fatal (bled out with parasitemias of over 25%) infections, but Panamanian monkeys generally survived. Colombian and Panamanian monkeys that spontaneously recovered from malaria infection were phenotypically indistinguishable from those which died. Karyotype analysis revealed that animals considered in this study were either Karyotype II (54 chromosomes) or II (53 chromosomes). Karyotype differences between individual monkeys did not correlate with increased susceptibility or resistance to malaria. Thus, the country of origin of owl monkeys appears to play a more important role in host susceptibility to malaria infection than karyotype.