MALARIA: The Origin of Malaria: The Hunt Continues

ScienceDaily (July 22, 2011) — The agent of malaria has been found in the greater spot-nosed monkey, also known as putty-nosed monkey (Cercopithecus nictitans), a small African primate derived from a line different to that of humans, gorillas and chimpanzees. This discovery challenges current thinking on the origin of the parasite and introduces a key element in the fight against malaria: knowing how it has adapted to the human species will make it possible to target its weaknesses. This work stems from research carried out by CNRS researchers in association with other organizations(1) and is published on the 4 July 2011 in the journal PNAS.

The greater spot-nosed monkey, Cercopithecus nictitans. (Credit: © Jean-Louis Albert, CIRMF, Gabon)

Malaria, also known as paludism, is one of the greatest global scourges. This pathology, which causes a million human deaths each year, is especially rampant in Africa. The question of whether the primary infection originated from rodents or birds has long remained unanswered. Also found in gorillas, it was thought that the parasite was specific to hominids(2).
By working on the subject, a team of CNRS researchers headed by Franck Prugnolle and François Renaud of the Laboratoire MIVEGEC(1)(CNRS/IRD/Université Montpellier 1), jointly with the Centre International de Recherches Médicales de Franceville in Gabon, and in collaboration with other organizations(4), has demonstrated the presence of Plasmodium falciparum, the agent of malaria, in the greater spot-nosed monkey (Cercopithecus nictitans), a small African monkey derived from a line different to that of humans. The origin of the parasite probably predates the origins of the African hominids line.
The presence of Plasmodium falciparum in this Old World Monkey opens the way to the analysis of the genome of the parasite found in this species. Comparing its sequence with that (already known) of falciparum in humans will enable researchers to discover the molecular signatures of the human parasite and to find out how it has adapted to humans. Knowing the weaknesses of the parasite will be a major asset in combating malaria.

(1)Centre International de Recherches Médicales de Franceville au Gabon, IRD, Université Montpellier 1, Université de la Méditerranée, Université de Toulouse, University of California and Université de Brazzaville.
(2)The hominids line comprises two branches: humans and large monkeys (gorillas, chimpanzees and orangutans).
(3)Laboratoire "Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle"
(4)Université de la Méditerranée, Université de Toulouse, University of California and Université de Brazzaville.

http://www.sciencedaily.com/releases/2011/07/110722130301.htm

MALARIA: African monkeys are infected byPlasmodium falciparum

Franck Prugnollea,1,2, Benjamin Ollomob,1, Patrick Duranda,1,Erhan Yalcindaga,1, Céline Arnathaua, Eric Elgueroa, Antoine Berryc,Xavier Pourruta,d, Jean-Paul Gonzaleze, Dieudonné Nkoghed,Jean Akianaf, Delphine Verriere, Eric Leroya,d, Francisco J. Ayalag,2, andFrançois Renauda,2

Recent molecular exploration of the Plasmodium species circulating in great apes in Africa has revealed the existence of a large and previously unknown diversity of Plasmodium. For instance, gorillas were found to be infected by parasites closely related to Plasmodium falciparum, suggesting that the human malignant malaria agent may have arisen after a transfer from gorillas. Although this scenario is likely in light of the data collected in great apes, it remained to be ascertained whether P. falciparum-related parasites may infect other nonhuman primates in Africa. Using molecular tools, we here explore the diversity ofPlasmodium species infecting monkeys in Central Africa. In addition to previously described Hepatocystis and Plasmodium species (Plasmodium gonderi and Plasmodium sp DAJ-2004), we have found one African monkey to be infected by aP. falciparum-related parasite. Examination of the nuclear and mitochondrial genomes of this parasite reveals that it is specific of nonhuman primates, indicating that P. falciparum-related pathogens can naturally circulate in some monkey populations in Africa. We also show that at least two distinct genetic entities of P. falciparum infect nonhuman primates and humans, respectively. Our discoveries bring into question the proposed gorilla origin of human P. falciparum.
http://www.pnas.org/content/108/29/11948.abstract

Primate malaria in Africa may be jumping species

Rachel Mundy : 7 July 2011


The malaria parasite was found in a spot-nosed guenon from Gabon : Flickr/donjd2

A malaria parasite from gorillas has been found in an African monkey, suggesting it has jumped species and may be able to transfer to humans.
The finding has led some malaria experts to suggest that if transfer between monkeys and apes has occurred then monkey-to-human malaria transmission may already be happening. They have called for more research to quantify the risks.
"The evidence is sufficient to warrant further investigation into the possibility that these parasites may also jump to humans," said Beatrice Hahn, a professor of medicine at the University of Alabama at Birmingham, United States. "We need to screen humans who live in flying range of mosquitoes that also bite primates, to establish whether they are susceptible to the primate parasites."
Wild forest-living gorilla populations are known to harbour a parasite strain that is closely related to the human malaria parasite Plasmodium falciparum. And macaque monkeys in South-East Asia carry another malaria parasite, Plasmodium knowlesi — a potential threat to humans.
But this is the first time that a P. falciparum strain similar to the one that causes human malaria has been found in an African monkey — the spot-nosed guenon from Gabon (Cercopithecus nictitans).
The fact that "the genetic differences from the human strain are so slight" raises the possibility that monkey and ape malaria may be transmitted to humans, said François Renaud, a researcher at the French National Centre for Scientific Research, in Montpelier, and co-author of the study published in the Proceedings of the National Academy of Sciences (5 July).
As humans come into closer contact with apes and monkeys as a result of deforestation, commercial hunting and population growth, the opportunity for the parasites to be transmitted to humans will increase.
"One single successful cross-species transmission event has the potential to result in a major human pandemic," Hahn, who was not involved in the study, told SciDev.Net. 

But David Conway, professor of biology at the London School of Hygiene & Tropical Medicine, United Kingdom, said the reservoir of malaria in African monkeys must be very small, given the low prevalence found in this study.
"Hopefully, monkey malaria will start to be recognised as an important area of research, but when examining the public health significance for humans, it is important to put the risk into context. Normal human malaria has a much higher prevalence, except in parts of South-East Asia where this has been reduced and the importance of malaria from monkeys has become more noticeable," Conway said.
Looking for human infections with monkey malaria is "like looking for a needle in a haystack", he said, adding that "there is every chance that human infections are occurring occasionally in the forest".
"In this particular case, the vector of malaria is the key determinant in determining any public-health risk," Conway said. "Identifying which species of mosquitoes transmits each parasite strain is a neglected area of research that needs additional funding."
http://www.scidev.net/en/news/primate-malaria-in-africa-may-be-jumping-species.html