'Consider the Use of DDT against a Child's Death of Malaria'
BYLINE: Neels Jackson
KwaZulu-Natal - While DDT has become a profanity amongst environmentalists because of the toxin's tendency to remain in the environment for a considerable timespan, KwaZulu-Natal's health department has taken the unusual step of once again utilising DDT in combating malaria.
The decision to reintroduce DDT must be seen against the background of KwaZulu-Natal being in the grip of a devastating malaria epidemic.
Provincial health department spokesman Dave McGlew said prior to 1995 less than 7,000 malaria cases were reported in the province. In 1992 the figures had dropped to 599. Since then the incidence of the disease has continued to increase:
1995: 4,000 cases without any reported deaths.
1996: 10,535 cases and 32 deaths reported.
1997: 11,400 cases and 38 reported deaths.
1998: 14,575 cases and 112 reported deaths.
1999: 27,206 cases and 220 reported deaths.
Professor Richard Hunt of the Zoology department at the University of the Witwatersrand explained that the Anopheles funestus mosquito had previously been the culprit in the spread of the disease.
The insect was the reason the Letsitle valley had been known as the valley of death. In northern KwaZulu-Natal these mosquitoes spread malaria to an area bisecting Eshowe and possibly even as far south as Durban.
With the advent of malaria eradication programmes utilising DDT had completely [Webmaster's Note:the proper words are _'temporarily eliminated_']
eradicated the species in South Africa. However, in areas such as Mozambique the mosquito survived.
The other malaria-carrying culprit mosquito is An. arabiensis.
Hunt emphasised that DDT spraying was only used inside homes in the eradication programmes. Buildings' inside walls, roofs and eaves were treated with the poison.
Mosquito breeding grounds were never sprayed, which made it a safe practice as far as the environment was concerned.
In 1996 however, a policy decision was taken and DDT was taken out of use in eradicating malaria. The programme switched to a group of poisons called pyrethroids, generally accepted as being more environmentally-friendly.
But with the huge upswing in cases of malaria the situation was reviewed. A provincial health department entomologist, Keith Hargreaves, who himself is now a malaria carrier [Webmaster's Note:P. falciparum infection clears completely after effective medicinal treatment. P. falciparum, the malaria species found in South Africa, does not relapse.], found An. funestus specimens inside homes sprayed with pyrethroids during a study.
Further studies showed the homes had been sprayed thoroughly and the poison was active. The insects had developed resistance to peritroids.
Dr Gerhard Verdoorn of the Trust for Endangered Nature's poison task group said the mosquitoes seem to "eat pyrethroids for dessert". The poison was however, still effective against An. arabiensis.
The results were described by McGlew as a "catch-22" situation. On the one hand there was the option to return to the effective poison with the bad name: DDT. On the other hand a human tragedy was in the making with more and more people dying of malaria.
DDT as an option is not attractive to anybody. McGlew added that after the decision had been taken everyone in the department was still uneasy about it.
Verdoorn added that DDT's worst attribute is its longevity. If a kilogram of the poison was left somewhere in the environment today, half of it will still be left in 11.5 years from now. After another 11.5 years, a quarter would still be "alive".
The poison is mainly lethal to insects, although birds and animals will die if large quantities are consumed. However, what does happen is that deposits build-up in the food chain, causing the thinning of egg shells in raptors such as vultures and fish eagles at the top end of the food chain. The birds lay healthy eggs, but the shells are so thin that they soon crack - causing a disruption in the birds' reproductive mechanisms.
The sober facts, however, are that DDT is the only poison on the market that will effectively eradicate [Webmaster's Note: proper word is _eliminate_ ] An. funestus - and the present malaria epidemic. Which was why the poison task group agreed to the use of DDT.
"One has to consider the use of DDT against the death of a three-year-old child of malaria," he said.
There are however, very specific conditions in using DDT. It is only permitted to be sprayed inside homes, under eaves and sheds. Poison task group inspectors are permitted to do unannounced inspections at any time.
Task group member Tim Snow is in the process of training people on the correct ways of spraying, to the extent of preventing the water they use to clean their equipment from flowing back into the ecosystem.
"There is no danger for those people whose homes are sprayed," Verdoorn said.
"People won't be harmed. During World War II trenches were sprayed with DDT to rid soldiers of lice and bedbugs without any serious consequences."
While controlled and limited use of DDT is still an option, Verdoorn has set his hopes on a new product under development by pharmaceutical company Bayer which may successfully eradicate An. funestus and have a much shorter viability in the environment.
Meanwhile he'll continue the battle against DDT. There is a general perception that it was banned worldwide, however it has only been banned in agricultural areas in some countries. The poison task group is campaigning to have it banned in all areas, with the exception of inside homes.
In the past two years Verdoorn has found and destroyed 8.5 tons of DDT. Together with the harvest protection association twice as much was destroyed.
If anyone is aware of anybody using or possessing DDT, Verdoorn should be contacted. He can be reached on 082 446 8946, anytime.
A study conducted by Professor Donald Roberts and colleagues of the University of Health Sciences in Bethesda, Maryland found that the incidence of malaria increased considerably in South American countries where the use of DDT had been banned.
They suggest that DDT was the cheapest way of efficiently [Webmaster's Note: proper word is _controlling_ ] eradicating malaria, adding that it should only be manufactured for use by governments in their malaria eradication programmes.
More about the study can be found at: this site
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