Monday, May 27, 2013

Chasing a Parasite

Burmese medics with the Shoklo Malaria Research Unit race to save a Burmese man's life after he collapsed with a fever caused by malaria

Malaria is a parasite spread by mosquitoes. It's been the scourge of mankind for millennia, first reported in China in 2700BC. Originally it was thought that malaria was an airborne disease (hence malaria, Latin for Bad Air) and originated around swamps (it was also called "swamp fever.") It wasn't until the late 19th century that we knew mosquitoes spread the disease. 

During World War II, malaria hospitalized more combatants than actual combat did. Medical science thought it had scored a win against the parasite with the development of drugs, including chloroquine, that killed the parasite but the victory was fleeting. The parasite mutated and by the 1970's drug resistant malaria came roaring out of the jungles of Southeast Asia and raced around the world, causing a sustained increase in deaths from malaria. 

Further research led to the development of malarone, a very expensive but effective drug that worked until the early 2000s when the parasite mutated again and again in Southeast Asia. Now another epidemic of drug resistant malaria is on the march and scientists are racing to contain it before it gets out of Southeast Asia and moves onto India and Africa. 

I went to Mae Sot, Thailand, to photograph doctors from the Shoklo Malaria Research Unit (SMRU) doing research into and treating malaria. Malaria has been effectively eliminated from Thailand but it is still endemic in Burma and Cambodia. As recently as 2009, SMRU doctors were able to cure over 95% of their patients using malarone and other treatments. 
A Dutch pediatrician examines a pregnant Burmese refugee who has malaria in Maela Refugee Camp north of Mae Sot. Malaria is especially dangerous for pregnant women and children.

Since then the cure rate has fallen. Precipitously. By 2012 they were only able to cure 60%-65% of malaria patients with the standard treatments and they were doing research on alternative treatments. 

The irony is that in the 20 years the SMRU has been treating malaria patients the actual incidence of malaria was dropping. 

It's been all but eliminated from most parts of Thailand and even in Burma its incidence was on the decline. The mosquito that carries the malaria parasite doesn't do well in urban environments, so cities like Bangkok, Ho Chi Minh City and Phnom Penh are largely malaria free. 

The mosquitoes thrive in a rural, jungle or swamp environment. As forests were clear cut to make way for agricultural and industrial development, the mosquito lost its natural habitat (one of few good things about deforestation) and mosquito eradication efforts, especially in Thailand, all contributed to a decline of malaria. Malaria had declined so much in the areas served by SMRU doctors that they had started focusing on other health concerns of the Burmese. Other fevers, child birth and pediatric issues, trauma are all treated by the SMRU doctors and medics. 

Malaria incidence is still in decline, but what concerns doctors are that the drug resistant malaria will spread to Africa, much like chloroquine resistant malaria did, and that drug resistant malaria will set back efforts to eliminate the disease from Southeast Asia. 

The malaria parasite does not spread from person to person, so patients don't need to be isolated. The mosquito picks up the parasite when it bites an infected person and spreads it when the mosquito bites another person. So one infected person in an otherwise cleared community can spread the disease to his and her neighbors. That is why drug resistant malaria could lead to an increase in the incidence of malaria in areas where the disease had been on the retreat. 

Mosquito nets have been touted as an effective preventive against malaria. They work in Africa but the nets aren't effective in Asia. 

In Africa the mosquitoes that spread the parasite are active after midnight, but in Southeast Asia, the mosquitoes are active around dusk. Not many people huddle under a mosquito net at 6PM, most are out, still working or enjoying the slightly cooler end of the day. So in Asia, malaria prevention means mosquito eradication or prevention through medications. 
A child critically ill with malaria waits on a life saving blood transfusion. A donor was found shortly after this picture was made. When I left doctors were waiting for blood tests to come back on the donor to make sure the donor had no blood borne pathogens that could infect the child

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