Natural infection of Plasmodium brasilianum in humans: Man and monkey share quartan malaria parasites in the Venezuelan Amazon.
BACKGROUND
The quartan malaria parasite Plasmodium malariae is the widest spread and best adapted human malaria parasite. The simian Plasmodium brasilianum causes quartan fever in New World monkeys and resembles P. malariae morphologically. Since the genetics of the two parasites are nearly identical, differing only in a range of mutations expected within a species, it has long been speculated that the two are the same. However, no naturally acquired infection with parasites termed as P. brasilianum has been found in humans until now.


METHODS
We investigated malaria cases from remote Yanomami indigenous communities of the Venezuelan Amazon and analyzed the genes coding for the circumsporozoite protein (CSP) and the small subunit of ribosomes (18S) by species-specific PCR and capillary based-DNA sequencing.


RESULTS
Based on 18S rRNA gene sequencing, we identified 12 patients harboring malaria parasites which were 100% identical with P. brasilianum isolated from the monkey, Alouatta seniculus. Translated amino acid sequences of the CS protein gene showed identical immunodominant repeat units between quartan malaria parasites isolated from both humans and monkeys.


CONCLUSIONS
This study reports, for the first time, naturally acquired infections in humans with parasites termed as P. brasilianum. We conclude that quartan malaria parasites are easily exchanged between humans and monkeys in Latin America. We hypothesize a lack of host specificity in mammalian hosts and consider quartan malaria to be a true anthropozoonosis. Since the name P. brasilianum suggests a malaria species distinct from P. malariae, we propose that P. brasilianum should have a nomenclatorial revision in case further research confirms our findings. The expansive reservoir of mammalian hosts discriminates quartan malaria from other Plasmodium spp. and requires particular research efforts.
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
Albert
A
Lalremruata
Servicio Autónomo Centro Amazónico para la Investigación y Control de Enfermedades Tropicales 'Simón Bolívar' (SACAICET), Puerto Ayacucho, Estado Amazonas, Venezuela.
Magda
M
Magris
Servicio Autónomo Centro Amazónico para la Investigación y Control de Enfermedades Tropicales 'Simón Bolívar' (SACAICET), Puerto Ayacucho, Estado Amazonas, Venezuela ; Cátedra de Salud Pública, Escuela de Medicina Luis Razetti, Universidad Central de Venezuela, Caracas, Venezuela.
Sarai
S
Vivas-Martínez
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
Maike
M
Koehler
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
Meral
M
Esen
Center for Global Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA.
Prakasha
P
Kempaiah
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
Sankarganesh
S
Jeyaraj
Center for Global Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA.
Douglas Jay
DJ
Perkins
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
Benjamin
B
Mordmüller
Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany ; Servicio Autónomo Centro Amazónico para la Investigación y Control de Enfermedades Tropicales 'Simón Bolívar' (SACAICET), Puerto Ayacucho, Estado Amazonas, Venezuela.
Wolfram G
WG
Metzger
D000818:Animals; D000882:Haplorhini; D006801:Humans; D008288:Malaria / Q000175:diagnosis / Q000469:parasitology*; D010271:Parasites / Q000502:physiology*; D010802:Phylogeny; D010961:Plasmodium / Q000502:physiology*; D015800:Protozoan Proteins / Q000378:metabolism; D014687:Venezuela
D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan
18S rRNA; Anthroponosis; Anthropozoonosis; CSP; Circumsporozoite protein; New World monkey; PCR; Plasmodium brasilianum; Plasmodium malariae; Polymerase change reaction; Quartan malaria; Sequencing; Small subunit ribosomal RNA; Venezuela; Yanomami; Zoonosis