Date Published: January 26, 2017
Publisher: Public Library of Science
Author(s): Alicia Fuentes-Ramírez, Mauricio Jiménez-Soto, Ruth Castro, Juan José Romero-Zuñiga, Gaby Dolz, Richard Culleton.
One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs.
Malaria is a vector-borne disease caused by protozoa of the Plasmodium genus, which are transmitted to human beings and to non-human primates through the bite of female blood-sucking mosquitoes of the genus Anopheles [1, 2]. Malaria parasites tend to be specific to each species, however, there are species of the parasite which infect both persons and monkeys, and cannot be differentiated morphologically, genetically or immunologically .
This work is the first cross-sectional study which combines diagnostic thick blood smear and molecular biology techniques (PCR and sequencing), to detect parasites of the Plasmodium genus in non-human primates in captivity in Costa Rica. Given that 84.9% of the population of monkeys living in captivity in 13 rescue centers were analyzed, and these centers receive animals from different parts of the country, this work is based on a strong representative sample of the population studied, which provides internal validity . In this study, the P. malariae/P. brasilianum parasite was found in three non-human primate species (A. palliata, A. geoffroyi and C. jacchus), which is consistent with what was reported by other researchers, who also found P. malariae/P. brasilianum in free-living monkeys in Costa Rica .
The P. malariae/P. brasilianum parasite was found in different species of non-human primates in captivity, and in different regions of the Southern part of Costa Rica, on both the Pacific and Atlantic coasts. The similarity of the sequences of the parasites found in humans and one monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important to include them in the control and eradication programs.