Natural Plasmodium infection in monkeys in the state of Rondônia (Brazilian Western Amazon)

Abstract

BackgroundSimian malaria is still an open question concerning the species of Plasmodium parasites and species of New World monkeys susceptible to the parasites. In addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. To aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the Amazonian state of Rondônia, Brazil, a state with intense environmental alterations due to human activities, which facilitated sampling of the animals.MethodsParasites were detected and identified in DNA from blood of monkeys, by PCR with primers for the 18S rRNA, CSP and MSP1 genes and sequencing of the amplified fragments. Multiplex PCR primers for the 18S rRNA genes were designed for the parasite species Plasmodium falciparum and Plasmodium vivax, Plasmodium malariae/Plasmodium brasilianum and Plasmodium simium.ResultsAn overall infection rate of 10.9% was observed or 20 out 184 monkey specimens surveyed, mostly by P. brasilianum. However, four specimens of monkeys were found infected with P. falciparum, two of them doubly infected with P. brasilianum and P. falciparum. In addition, a species of monkey of the family Aotidae, Aotus nigriceps, is firstly reported here naturally infected with P. brasilianum. None of the monkeys surveyed was found infected with P. simium/P. vivax.ConclusionThe rate of natural Plasmodium infection in monkeys in the Brazilian state of Rondônia is in line with previous surveys of simian malaria in the Amazon region. The fact that a monkey species was found that had not previously been described to harbour malaria parasites indicates that the list of monkey species susceptible to Plasmodium infection is yet to be completed. Furthermore, finding monkeys in the region infected with P. falciparum clearly indicates parasite transfer from humans to the animals. Whether this parasite can be transferred back to humans and how persistent the parasite is in monkeys in the wild so to be efficient reservoirs of the disease, is yet to be evaluated. Finding different species of monkeys infected with this parasite species suggests indeed that these animals can act as reservoirs of human malaria.

Molecular interactions governing host-specificity of blood stage malaria parasites

“…While P. vivax infection of Old World monkeys has not been documented, New World monkeys appear to be highly susceptible [69,70]. Interestingly, the CMAH gene was independently pseudogenized in the ancestor of New World monkeys [71], potentially offering a permissive, human-like cellular environment for human-adapted parasites that require the expression of Neu5Ac for invasion.…”

Nonhuman Primates

“…Some of the common malarial parasites that infect NHPs include (1) P. knowlesi, a quotidian parasite that naturally infects M. fascicularis and M. nemestrina and may cause severe fatal infection of M. mulatta; (2) P. cynomolgi, a tertian parasite that naturally infects M. fascicularis, M. nemestrina, M. cyclopis, and several species of leaf monkeys and causes a disease in M. mulatta similar to P. vivax in man; (3) P. simium, a tertian parasite found in southern Brazil in spider and howler monkeys; and (4) P. brazilianum, a quartan parasite found naturally in spider, howler, capuchin, owl monkeys, and squirrel monkeys having a distribution from Mexico to Peru that is similar to P. malariae in man (Araũjo et al, 2013). Plasmodium infection can be transmitted as a bloodborne pathogen from animals to human handlers and poses a serious zoonotic risk (Cox-Singh, 2012).…”

Occurrence of immature forms of culicids (Insecta: Diptera) in the northeastern region of Brazil

“…(K.) bellator in this area is relevant, considering its importance as a vector of protozoa of the genus Plasmodium (FORATTINI et al, 1999). Indeed, the possibility that monkeys might be infected by Plasmodium that affects humans and vice versa has been confirmed, thus demonstrating the zoonotic potential of these parasites (ARAÚJO et al, 2013).…”