Monkey malaria

"Researchers in Malaysia have identified...an emerging new form of malaria infection" that is a "potentially deadly" strain of the disease (ScienceDaily). "Malaria kills more than a million people each year. It is caused by malaria parasites, which are injected into the bloodstream by infected mosquitoes" (Daneshvar).

"Recently, researchers at the University Malaysia Sarawak...showed that P. knowlesi, a malaria parasite previously thought to mainly infect only monkeys - in particular long-tailed and pig-tailed macaques found in the rainforests of Southeast Asia - was widespread amongst humans in Malaysia." After several similar reports, P. knowlesi has been deemed "the fifth cause of malaria in humans" (ScienceDaily).

P. knowlesi malaria is particularly dangerous because it "can easily be confused with P. malariae", a more benign form of malaria (ScienceDaily). Under the microscope, the two strains appear nearly identical, but the strains are very different in severity and deadliness. "One of the most significant findings of the study is that Plasmodium knowlesi was found to have the ability to reproduce every 24 hours in the blood -- meaning infection was potentially deadly. This, according to the researchers, meant early diagnosis and treatment were crucial" (Kounteya).

A universally low platelet count is another curious characteristic of this strain of parasite. "In other human forms of malaria, this would only be expected in less than eight out of ten cases." But, "all of the P. knowlesi patients - including those with uncomplicated malaria - had a low blood platelet count...The researchers believe the low blood platelet count could be used as a potential feature for diagnosis of P. knowlesi infections." (ScienceDaily).

"Recently, there have been cases of European travellers to Malaysia and an American traveller to the Philippines being admitted into hospital with knowlesi malaria following their return home" (ScienceDaily). This deadly strain of malaria may potentially spread across the globe and infect millions if it is not adequately treated and controlled.

Sources:
Daneshvar C, et al. Clinical and laboratory features of human Plasmodium knowlesi infections. Clin Infect Dis. 2009;49(6):852-60.

Kounteya Sinha. The Times of India. "Monkey malaria spreads to humans in South-east Asia". 11 September 2009.

ScienceDaily. In Humans. Retrieved September 13, 2009, from http://www.sciencedaily.com­ /releases/2009/09/090909103004.htm

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