非洲国家使用DDT抗疟疾

The chemical pesticide DDT has been banned by most countries for use in agriculture, but some continue to use it indoors to kill insects that carry malaria.

In Zambia, it’s an important part of the government’s malaria control program, and the controlled use of DDT spray has led to a reduction in malaria cases over the years.

Other African countries are facing a rise in the number of cases and several African governments are considering the carefully monitored use of DDT as part of their strategy against the disease.

In Malawi, for example, the Department of Health may undertake a DDT spray program in malaria prone-areas.

There is no doubt that DDT is very effective in killing mosquitoes.  The problem lies in what other effects DDT may have on human health, wildlife, environment, horticulture and crops.
Malawi’s secretary of health, Chris Kang’ombe, was part of a delegation that visited Zambia to learn how the use of DDT has helped reduce malaria there.

Kang’ombe is convinced that DDT can help reduce the spread of malaria in Africa -- if handled under controlled conditions by trained personnel and monitored by government agencies.

He says, “DDT is used for indoor spraying.  It is used to only spray within, inside the house, dwelling houses.  What we have learnt (from Zambia) and we know from our experience here (in Malawi), the other chemicals [are active for] up to about two or three months, whereas with DDT you are talking of six months plus. So in terms of “residue effect,” it (DDT) is better, and also eventually the cost of indoor spraying…will be much cheaper, more cost effective than using other chemicals. “

While authorities in Malawi are still considering using DDT in malaria control, a thorny issue has arisen.

The Tobacco Control Commission is against the idea of using the pesticide.  Tobacco is the mainstay of Malawi’s economy, and there’s fear that Western consumers will not buy it if there are any traces of DDT on the crops.  So the commission will likely require careful monitoring if Malawi is to start using DDT in malaria control.

Similar views are shared by Uganda’s Network on Toxic Free Malaria Control.  The network is against the use of DDT as a malaria control strategy.

“We have no law specifically for DDT,” says Network Secretary General Ellady Muyambi  . “ We have no trained manpower.  We do not have equipment in terms of transportation facilities, in terms of storage facilities, in terms of disposal facilities, in terms of laboratories for chromatography.   We do not have the capacity.  We are still relaying on donor funding and we are saying why can’t our country use its own resources to deal with its own problems, especially these ones like malaria.,” says Muyambi.

Also involved in the DDT debate is Kenya, another country debating whether to use the pesticide.

Shrikant  Bhatt professor of medicine at the University of Nairobi in Kenya explains why the controlled use of DDT should be reintroduced. “We are almost getting defeated by the pandemic that is occurring due to malaria.  [Anti-malarial] drugs are gaining resistance [to the parasite].  You know we have very few drugs which we can use as effective means of controlling malaria.  So, I think we do not have any option but to reintroduce DDT in a limited way, [like] spraying DDT indoors or using it in endemic areas we should be able to contain the malaria pandemic,” he explains.

The International Centre for Insect Physiology and Ecology (ICIPE), also based in Kenya, is taking different approach.

John Githure a researcher at the centre says  “ICIPE is largely concentrating on how we can come up with innovative ways or even using available products to kill the mosquitoes at larval stage. “

One such product uses soil-dwelling bacteria called bacillus thuringiensis, or BTi.
Githure says ,”we are trying to introduce that in Africa and ICIPE have of course gone ahead to construct a demonstration factory that will be able to at least make the product BTi available, affordable and accessible to the community to use for mosquito control.”

Meanwhile, the government and various organizations including Melinda and Bill Gates Foundation are encouraging free distribution of insecticide-treated mosquito nets and sleeping under bed-nets as short term measure for malaria control.

For VOA Africa...I am Sanday Chongo Kabange in Lusaka, Zambia.