Scandalously scarce resource (Nature, Oct 3, 2002;419:417) for malaria control!
Malaria is an acute infectious disease caused by the parasites called Plasmodia and spread by the the vector, the female anopheles mosquito. Control of this dreaded menace would therefore involve three living beings: Man (The host), Plasmodia (The agent), and Anopheles mosquito (The vector). And due to this reason alone, control of malaria is a formidable task. The international efforts on malaria control were highly successful in the late 50’s and early 60’s. However, due to various reasons, the malaria control programmes received setbacks all over the world and today it has come back with a vengeance. Control of malaria is possible only by concerted community efforts. Relying only on the government machinery for the control of this problem will only heighten the dangers.
Malaria control measures:
W.H.O. Ministerial Conference held in October, 1992 at Amsterdam evolved a Global Strategy for Malaria Control. The strategy broadly suggests de-emphasis on vector control and renewed emphasis on treatment. Early diagnosis and treatment; prevention of deaths; promotion of personal protection measures like use of ITMs; epidemic forecasting, early detection and control; monitoring, evaluation and operative research and integration of activity in Primary Health Centres are the salient aspects of this strategy.
The control of malaria involves control of 3 living beings and their environment. Man, the host is a moving target and can take the disease with him to far and wide. Mosquitoes are moving, highly adaptable and have shown resistance to insecticides. It is therefore important to target non-flying eggs and larvae. The parasite also is highly adaptable, hides in humans and mosquitoes and has also developed resistance to drugs. Therefore, for effective malaria control, target man first, control mosquitoes next and keep trying to tackle the parasite with development of effective drugs and vaccines.
Control of malaria is a complex chain of measures that often complement one another. The diagram on the left depicts this control chain: For example, by taking personal protective measures, three things can be achieved – prevention of malaria in the given individual, thus reduced parasite load and reduction in spread, and by denying blood meal to the mosquito the egg laying is also hampered! In the recent years, more emphasis is being laid on early diagnosis and treatment, on personal protection especially with insecticide treated bednets and on biological vector control. By these means, it is intended to minimise use of potentially harmful chemical insecticides.
Man, the Host: Treat the affected, protect the unaffected. Problem are compliance, accessibility and availability of treatment and protective measures, mostly due to poverty and backwardness.
Parasite, the Agent: Ensure full treatment; kill the asexual forms and prevent the progression of disease, kill the sexual forms and prevent the spread to mosquitoes. Problem is Drug resistance
Mosquito, the Vector: Prevent breeding, prevent entry into houses, prevent bites to humans. Problems are resistance to insecticides and compliance by humans
Man’s Role in Malaria Control: Man is the most important link in the malaria control chain. He can be made to understand the problem and he can help in breaking the chain at multiple points. Therefore great emphasis should be laid on educating the people about malaria and its control, so that common people can effectively contribute in controlling this disease. This includes education of doctors about the need for early diagnosis and prompt treatment of malaria.
- Early diagnosis and treatment – treat early to reduce parasite load, hence spread; prevent deaths
- Treat completely to prevent spread and relapse
- Ensure compliance with complete treatment
- Personal Protection- prevent malaria by using bed nets, insecticide sprays etc., and by chemoprophylaxis.
- Seek his help in mosquito control
1. Early diagnosis and treatment: This is a very important aspect of malaria control. In fact, early detection and treatment of the disease itself is enough to control this epidemic in its early stages. By this, the parasite load in the community is reduced, thereby reducing the transmission of the disease.
Presumptive treatment of all cases of fever is very important. Tests for malarial parasite should be done in all cases of fever, and presumptive treatment with first full dose of chloroquine should be administered. Chloroquine is highly effective as schizonticidal against all species of malaria and is also gametocytocidal against all except P. falciparum. Thus, by administering chloroquine to all cases of fever, it is possible to sterilize the gametocytes and thus prevent the spread to mosquitoes.
Whenever resistance to chloroquine is known or suspected, second line anti malarials should be used to treat P. falciparum malaria.
2. Radical treatment: All confirmed cases of fever should be administered radical treatment with primaquine. A single dose of primaquine must be administered in P. falciparum malaria to sterilize the gametocytes. A 14 days course of primaquine should be administered in P. vivax infection to destroy the hypnozoites in the liver and thus to prevent relapse.
3. Ensure compliance: Complete treatment should be ensured. If the patient vomits the drugs within an hour of ingestion, the same should be repeated. Incomplete treatment fails to clear the parasitemia and thereby aids spread. Many patients fail to complete the treatment due to either negligence, lack of proper education or sometimes due to adverse effects.
4. Personal protection: Man should be encouraged to protect himself against malaria. Personal protection measures include protection against mosquito bites and chemoprophylaxis against malaria.
Protection against mosquito bites: People living in endemic areas as well as travelers to such areas should be educated and encouraged to use protective measures against mosquito bites. These include closing the doors and windows in the evenings to prevent entry of mosquitoes into human dwellings; using mosquito repellant lotions, creams, mats or coils and regular use of bednets. Using bednets is one of the safest methods of preventing and controlling malaria. Now Insecticide Treated Bednets are available and it has been found in various studies that use of these ITMs leads to a 19% reduction in child mortality and 40-60% reduction in infection.
As mentioned above, protection against mosquito bites, especially the use of mosquito nets, has a spiraling effect on malaria control. By this measure, blood meal is denied for the female mosquito and this prevents development of eggs and hence a reduction in mosquito population and transmission.
For more details See Mosquito Control
Chemoprophylaxis: Travelers to endemic areas and high risk individuals living in endemic areas (pregnant, elderly, patients with end organ failure) should be started on chemoprophylaxis against malaria. This involves taking antimalarial drugs every week (some drugs may have to be taken everyday) so as to suppress malaria.
For details See Chemoprophylaxis
New Papers:
- Richard W. Steketee. Good News in Malaria Control… Now What? Am. J. Trop. Med. Hyg., 80(6), 2009, pp. 879–880. Available athttp://www.ajtmh.org/cgi/reprint/80/6/879
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