Can Malaria Be Eradicated?

Count me as a skeptic. Malaria will not be eradicated, at least not in our lifetime. The Bill and Melinda Gates Foundation has taken on the eradication of malaria in what may be a quixotic cause. The current state of the art in protecting Africans from becoming infected with malaria is insecticide impregnated bednets.

Malaria can be eradicated from certain geographical areas. The United States is a good example. This effort was successful primarily due to ridding ourselves of the vector - the mosquito carrier of malaria.

There are several factors necessary for malaria to thrive. First, you need to have the proper species of mosquito vector. It has to be certain species of the Anopheles mosquito. The vector of malaria in Africa is Anopheles gambiae which prefer to feed on people indoors, thus the effectiveness of bednets (and of insecticides such as DDT which are sprayed indoors). Second, you need a human population for human malaria to be transmitted. Lastly, you need the proper malaria parasite. Malaria parasites are very species specific. There are 4 species of malaria that infect humans: Plasmodium vivax, P. falciparum, P. ovale and P. malariae. The killer species of malaria is P. falciparum.



Malaria can be epidemic, as it was in the USA or endemic as it is in most of Africa. In endemic malaria, the disease is present all year, whereas endemic malaria is seasonal. Endemic malaria is often called "stable malaria" and epidemic malaria called "unstable malaria". Much more about the geographic distribution of malaria in Africa can be learned at Mara.org.

In the 1950's, with the discovery of anti-malaria drug chloroquin and the insecticide dichloro-diphenyl-trichloroethane(DDT), a somewhat successful effort to eradicate malaria was undertaken by the World Health Organization. A good example of this effort was seen in Sri Lanka. The number of malaria cases in Sri Lanka dropped from 1 million cases in 1955 to 18 cases in 1963. Unfortunately, keeping the levels of malaria at that level was a very expensive proposition. Development of insecticide resistance by the mosquito and drug resistance by the malaria parasite did not help. In 1969 the WHO admitted defeat and the efforts to eradicate malaria globally was abandoned.

What about anti-malaria drugs? Drug companies have no incentive to discover new anti-malarial drugs because the very countries that need such drugs cannot afford to buy them. Artemisinin (qinghaosu), a chemical compound derived from the shrub Artemisia annua is one of the latest drugs used to treat malaria. But malaria parasite resistance to this drug is developing.

What about an anti-malaria vaccine? Efforts to develop such a vaccine have been ongoing since the late 1960's. Three types of vaccines could be potentially effective against malaria. Vaccines against the blood stages (merozoites) of the parasite; vaccines against the liver stages (sporozoites)of the parasite and vaccines that would result in killing the parasite while inside the mosquito (gametocytes). None of the vaccines tested thus far result in 100% clearance of the parasite.

Will malaria be eradicated any time soon? It is unlikely. Use of drugs, insecticides, public health measures and a lot of money could result in a great reduction of malaria in some regions of the world. But eradication of malaria is not in the near future. Moreover, we need to worry about the effects of global warming on the spread of malaria.