Thursday, November 08, 2007

Sustainability of Malaria Control efforts through Chemicals

The annual incidence of malaria was estimated at around 75 million cases in 1953 with about 8 lakhs deaths annually. To combat this menace, the Government of India launched the National Malaria Control Programme in April 1953.

It proved highly successful and within five years the incidence dropped to 2 million.

The programme was changed to a more ambitious National Malaria Eradication Programme in 1958.

By 1961 the incidence dropped to a mere 50,00 cases a year. But since then the programme suffered repeated set-backs due to technical, operational and administrative reasons and the cases started rising again.

Malaria has now staged a dramatic comeback in India after its near eradication in the early and mid sixties.

During the period of resurgence of malaria, certain states like Uttar Pradesh, Bihar, Karnataka, Orissa, Rajasthan, Madhya Pradesh and Pondichery are found to be worst affected, particularly with increasing incidence of P. falciparum infection.

National Malaria Eradication Programme has been now renamed as National Anti Malaria Programme.

Malaria is an infectious disease caused by the parasite called Plasmodia. There are four identified species of this parasite causing human malaria, namely, Plasmodium vivax, P. falciparum, P. ovale and P. malariae. It is transmitted by the female anopheles mosquito. It is a disease that can be treated in just 48 hours, yet it can cause fatal complications if the diagnosis and treatment are delayed.

* Malaria affects more than 2400 million people, over 40% of the world's population, in more than 100 countries in the tropics from South America to the Indian peninsula. The tropics provide ideal breeding and living conditions for the anopheles mosquito, and hence this distribution.
* Every year 300 million to 500 million people suffer from this disease (90% of them in sub-Saharan Africa, two thirds of the remaining cases occur in six countries- India, Brazil, Sri Lanka, Vietnam, Colombia and Solomon Islands).
* WHO forecasts a 16% growth in malaria cases annually.
* About 1.5 million to 3 million people die of malaria every year (85% of these occur in Africa), accounting for about 4-5% of all fatalities in the world.
* One child dies of malaria somewhere in Africa every 20 sec., and there is one malarial death every 12 sec somewhere in the world.
* Malaria kills in 1 year what AIDS killed in 5 years. In 15 years, if 5 million have died of AIDS, 50 million have died of malaria.
* Malaria ranks third among the major infectious diseases in causing deaths- after pneumococcal acute respiratory infections and tuberculosis. It is expected that by the turn of the century malaria would be the number one infectious killer disease in the world.
* It accounts for 2.6 percent of the total disease burden of the world. It is responsible for the loss of more than 35 million disability-adjusted life-years each year.
* Every year ~ 30000 visitors to endemic areas develop malaria and 1% of them may die.
* Estimated global annual cost (in 1995) for malaria: US$ 2 billion (direct and indirect costs, including loss of labour).
* Estimated worldwide expenditure on malaria research: US$ 58 million, one thousandth of the US$ 56 billion spent globally on health research annually.
* Estimated annual expenditure on malaria research, prevention and treatment: $ 84 million.
* Estimated worldwide expenditure per malaria fatality: $ 65; as compared to $ 3274 for HIV/AIDS and $ 789 for asthma. That is to say, one HIV/AIDS death is equal to about 50 malaria deaths!

Malaria was nearly eradicated from most parts of the world by the early 60's, owing largely to concerted anti malarial campaigns world over under the guidance of the World Health Organization.

The following are some of the reasons for the resurgence of malaria:
Man made Complacency and laxity in anti malarial campaigns; conflicts and wars; migrations; deteriorating health systems; poverty
Parasite Drug Resistance
Vector Insecticide Resistance and ? ban on DDT
Environment Global Warming - increased breeding and life span of the insect vector
Jet Age Shrinking World - spread of malaria from endemic areas to all other parts of the world

1. Which chemicals are used to prevent Dengue-Malaraia? How they are harming environment and human being ?

Answer: Chemical Control measures for malaria prevention include use of Indoor Residual Spray with insecticides recommended under the programnme, use of chemical larvicides like Abate in potable water, aerosol space spray during day time and Malathion fogging during outbreaks. Although banned in developed countries, DDT is still being used in some developing countries to control malaria, but the debate is continuing.

Chemical control measures for Dengue prevention include larvicides, adulticides like Temephos (larvicides), an organophosphate, Pyrethrum (adulticide) and Malathion (adulticide) are used.

DDT residues remain in topsoil up to 7-8 cm and being immobile rarely contaminates ground water. Half-life of DDT residues in temperate soil is estimated to be 2-15 yr as against 6-14 months in tropical and subtropical soils. Similar is the case with other chemicals that enter our food chain.

DDT causes chronic liver damage cirrhosis and chronic hepatitis, endocrine and reproductive disorders, immuno suppression, cytogenic effects, breast cancer, Non hodkins lymphoma, polyneuritis.

Malathion and its oxygen analog malaoxon are both quite carcinogenic and have been linked with increased incidence of leukemia in mammals. Chronic health effects include: suspected mutagen and teratogen, delayed neurotoxin, allergic reactions, behavioral effects, ulcers, eye damage, abnormal brain waves and immuno-suppression. Contrary to what the public is being told by the Agriculture Industry and some governmental agencies, scientists are stating that Malathion (even at low levels) is in fact, a harmful chemical.

Chlorpyrifos is also used against mosquitoes. It has chronic neurobehavioral effects like persistent headaches, blurred vision, unusual fatigue or muscle weakness, and problems with mental function including memory, concentration, depression, and irritability.

Fenitrothion used against domestic insects and mosquitoes Human epidemiological evidence indicates fenitrothion causes eye effects such as retinal degeneration and myopia. Chronic exposure to Fenitrothion can cause frontal lobe impairment. Organo-phosphates are suspected of causing neurologic deficits.

2. What can substitute these chemicals ?

Answer: Biological Control measures for Malaria include use of larvivorous fish in ornamental tanks, fountains etc. and use of biocides.

Biological Control for Dengue includes use of larvivorous fish are recommended for control of Ae. aegypti in large water bodies or large water containers and Endotoxin-producing bacteria, Bacillus thuringiensis serotype H-14 (Bt H-14) has been found an effective mosquito control agent.

It is noteworthy that more effective and safer approaches to malaria control are now being used in many countries. For example, Vietnam reduced malaria deaths by 97% and malaria cases by 59% when they switched in 1991 from trying to eradicate malaria using DDT to a DDT-free malaria control program involving distribution of drugs and mosquito nets and widespread health education organized with village leaders. Mexico phased out DDT use in 2000 and implemented a successful integrated and community-based approach.

3. A number of people lost their lives due to this. why government is not banning the use of these chemicals?

The restriction permits indoor residual sprays of DDT in malaria control as per the WHO specifications for its production and following safety precautions for its proper use and disposal. Phasing out of DDT is delayed till an effective, affordable and safe alternative is available. In such a backdrop, the strong recommendation of WHO for indoor use of DDT to fight against malaria in September, 2006 that gave a clean bill to use of DDT to combat malaria where he vectors are still susceptible to DDT is believed to be the result of corporate influence especially from the pesticide industry.

The traditonal malaria control strategy has been the spraying of insecticides. Spraying of insecticides (DDT, HCH, Malathion)

As to Malathion, there are two types of malathion that can be used in medical health effects research. One is the "purified form" (which is approximately 99.9% malathion) and the other is called "technical grade" (which is approximately 96.5% malathion). The technical grade is approximately 10 times stronger in causing death to laboratory animals.

Perhaps the most sensitive of all forms of wildlife to exposure to malathion are the "dwarf lizards." These reptiles perform a service consuming significant amounts of other small insects. Lizards were exposed to malathion at levels of only 1 milligram of malathion per kilogram body weight (mg/kg) - 2 mg/kg - and 3 mg/kg. Each dosage caused significant damage to the animal's livers, kidneys, and small intestines. Note, these exposure levels are extremely small as the amount needed to cause death in most mammals is well above 500 mg/kg.

The researchers concluded by stating "Uncontrolled use of malathion or related compounds will certainly endanger not only the lives of lizards but also affect food chain and ecological balance of nature negatively."

The currently used pesticides globally cause about 20,000 deaths annually by accidental and deliberate/intentional poisoning. Unsafe spraying practices, hazardous transport, lack of storage, leakage to agriculture and poor disposal of waste etc. are major unaddressed issues.

4. what are environmentalist doing against this ?

As a result of the campaign by environmentalists, India is a signatory to Stockholm Convention on persistent organic pollutants (POPs) that has identified DDT as one of the 12 POPs that are banned. But DDT ban has certain restrictions applicable to countries for its continued use. the ban exempts its use in public health emergencies like outbreaks of malaria.

Environmentalists are arguing with the policymakers saying that resurgence of malaria calls for paradigm shift from the insecticidal to the ecological approach such as free or low-cost access to neem oil. Research shows that the natural pesticide "pyrethrum" has characteristics which make it especially effective for eliminating biting mosquitoes without harming the environment or public health.

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