Although it's not an infection that many of us take notice of, malaria is still a huge problem worldwide. In 2006, there were 247 million cases worldwide, and 881,000 died from the infection. In Africa, 2,000 children die from malaria every day. It may be eradicated from North America, Europe, Russian, and Australia, but this is a disease endemic to Africa, South America, and Asia, and it continues to cause pervasive problems in those countries.
The name malaria comes from the Latin, mal meaning bad, and aria meaning airs. It was believed to be contracted by breathing the miasma that arose from swampy areas. While the ancients didn't know the real cause, a protozoan parasite, they had the location correct, because of course mosquitoes breed in swampy areas or stagnant water.
Since the beginning of history, malaria has killed half of the people that have died on the planet, more than all wars, famines, and other epidemics combined. It is believed to have contributed to the fall of the Roman Empire as much as any other disease. A malaria epidemic in the year 79 laid waste to the Campagna area, where crops were grown. Its fields were untended and its villages were deserted; the area retained a low population for most of the next several centuries, and malaria wasn't eradicated from the region until the late 1930's.
Because of the prevalence of the parasite in Africa and the surrounding areas, genetic mutations developed that conferred immunity to some or all of the different strains. Sickle cell in those of African descent and thalassemia in those of Mediterranean descent cause a malformation in red blood cells that leave the cells impervious to infection. Other genetic mutations arose that confer resistance, and while these abnormalities may have protected against the infection, they certainly have their own serious consequences.
Malaria was a major problem in U.S. until the early 20th century. Presidents Washington and Lincoln had it; hundreds of thousands of Civil War soldiers contracted it; the infection traveled to California with the Gold Rush of 1849; and it killed many American Indians. The pesticide DDT proved effective in killing the mosquito that transmits the parasite, but the insects quickly developed resistance. It was also eventually found that DDT interrupted the ecological balance, resulting in other diseases like plague and typhus, and it was finally found to poison birds, fish, and mothers' milk. DDT was banned in the U.S. in 1972, but is still used in some tropical regions.
The protozoan is transmitted by the bite of the female Anopheles mosquito. Symptoms include fever and chills occurring in regular cycles, flu-like symptoms, sweating, and an enlarged spleen. Treatment of choice is chloroquine, although one strain is usually resistant and treated with quinine. When traveling to areas where malaria is endemic, prophylactic treatment with mefloquine is recommended. While generally only one strain can result in rapid death, part of malaria's covert danger is chronic anemia, which weakens the patient and makes them more susceptible to other diseases.
Most cases in the U.S. are in those who have traveled to endemic areas. While it's usually a rarity in U.S. laboratories, I was fortunate to work for the past ten years in a lab located in a city with several colleges that send students and/or missionaries abroad. We had a much higher rate of seeing malarial infections than in other places I worked, and it was a wonderful chance to learn. There are four species of Plasmodium that cause human malaria: falciparum, malariae, vivax, and ovale. It's important to speciate, because P. falciparum is by far the most deadly of the species, and causes the most deaths, and is also the one that is most resistant to treatment. We look at blood smears to see the parasites infecting the red blood cells, and many things have to be taken into account to identify the species: whether the red blood cells are enlarged or not; the presence of stippling, or dots within the cells; fimbriation, or feathered edges on the cells; whether there are multiple parasites in one cell; the various stages of parasite development; and the percentage of cells affected. Obtaining a patient's travel history is vital, because certain species are more common in certain areas--southeast Asia versus the west coast of Africa, for example.
As soon as I saw this picture, I said, “That’s falciparum.” Why? See those crescent-shaped purple structures in the middle? Those are the banana-shaped gametocytes of P. falciparum, and no other species has them. There are also cells that have more than one parasite in them, and that’s typical of falciparum.
Early diagnosis is crucial and can mean the difference between whether a patient lives or dies. Doctors in non-endemic areas don't necessarily think of malaria when a patient presents with flu-like symptoms. That's why a travel history is so important. We witnessed it a few years ago when a local family traveled to their African homeland. Although they took prophylactic drugs, they all contracted a resistant form of the infection. Not all of them survived, I'm sad to say.
While still a devastating and prevalent infection and still a terrible problem in Africa and other developing areas (where people cannot afford the expensive treatments), there is progress and hope. Groups like Nothing But Nets distribute mosquito nets treated with insecticides to African families to prevent the infection; The Gates Foundation provides grants for researchers attempting to find treatments and cures and is committed to eventually eradicating the disease; the drug company Novartis is providing Coartem, a very effective antimalarial drug, at a loss in order to treat patients in the developing world. Despite the monetary loss, the CEO of Novartis, Dr. Daniel Vasella, says, "We had the drug and the knowledge to help. It was our responsibility to be engaged."
I think most of us, with our multiple vaccinations, easy access to antibiotics, and increasing emphasis on preventive care, can't comprehend the effect that an endemic infection like malaria can have on a population and country. A populace weakened by hunger and disease has a much greater struggle in trying to make lives for themselves and improve their country. I applaud all of these companies and organizations, and those who contribute to them, for trying to make a difference in the lives of those who many find all too easy to ignore.
Sources:
Cartwright, Frederick F. Disease and History. New York: Dorset Press; 1972
Karlen, Arno. Man and Microbes. New York: Touchstone; 1996
Nikiforuk, Andrew. The Fourth Horseman. London: Phoenix; 1993
Kingsbury, Kathleen. "A Better Deal on Malaria." Time, March 9, 2009
Malaria. (2009, March 2). In Wikipedia, The Free Encyclopedia. Retrieved 23:21, March 9, 2009, from http://en.wikipedia.org/w/index.php?title=Malaria&oldid=274383494
