/ 20 November 2009

Lesser of two evils

The malaria squad will be out and about spraying DDT in Limpopo this summer, despite new research linking intersex cases in Limpopo to the controversial pesticide.

New research from the University of Pretoria has linked intersex disorders to the spraying of DDT in northern Limpopo to fight malaria.

The study was done in the region where running champion Caster Semenya grew up.

Researchers found that boys with urogenital birth defects were 33% more common in villages sprayed with DDT. The two-year study at the Tshilidzini Hospital near Thohoyandou included 2396 newborn boys whose mothers had been exposed to DDT and 914 whose mothers had not.

DDT affects boys more than girls because it mimics the effects of the female hormone oestrogen and is an antiandrogen agent.
One of the researchers, Professor Riana Bornman, said in the worst cases the researchers encountered newborn boys who resembled girls.

Researchers also recognise the hard truth about DDT: its links to intersex disorders and other diseases may be real, but so is DDT’s brutal success in curbing malaria.

South Africa is between a rock and hard place. Said Bornman: “It is a catch-22 situation. Though the World Health Organisation [WHO] is looking at other options, there is not much around that is as effective as DDT.”

DDT is a controversial pesticide, the harmful effects of which have been debated since the early 1970s when it was first linked to cancer, diabetes, low birth weight, miscarriages, birth defects in boys and infertility.

Though locally and internationally banned as a pesticide since 2001, DDT’s effectiveness in fighting malaria resulted in a WHO exemption for its use in this regard — under strict controls.

Not everyone believes DDT is linked to chronic illnesses.

“The negative effects of DDT have not been substantially proved,” said Dr Rajendra Maharaj, director of the Malaria Research Programme at the Medical Research Council.

The government also denies that DDT affects human health.

“The department of health has been spraying DDT since the 1940s and has not experienced any harmful effects of DDT [on] human health,” said the department’s spokesperson, Fidel Radebe.

Most people welcome the malaria squad with open arms, because the toxic mist they bring keeps this silent killer at bay.

Said Radebe: “Interestingly, communities that were initially concerned … called us back to spray the chemical after it was discontinued in the late 1990s due to the huge epidemic that occurred when DDT spraying was curtailed.”

Statistics tell the story of how compellingly successful DDT is against fighting malaria in South Africa.

In 1996 the government decided to stop using DDT because of environmental concerns. Up until then the average annual number of malaria cases was fewer than 10000, and deaths rarely exceeded 30 a year.

But four years later the disease had made a dramatic comeback. In 2000 the number of malaria cases spiked to more then 65 000 and 458 people died.

DDT was reintroduced after mosquitoes became resistant to pyrethroid, the “safer” pesticide with which the government replaced DDT. The intervention immediately made an impact.

In 2001 malaria declined nationally to 26506 cases and the number of deaths dropped to 119. Between 2000 and 2008 malaria cases were reduced by 88% to 7796 cases, with 46 deaths recorded.

DDT critic Professor Leslie London, from the University of Cape Town’s Occupational and Environmental Health Unit, sees no alternative.

“It is a simple trade-off,” he said. “DDT is certainly not safe. But it certainly is the lesser harm, though it is not without harm. It is highly persistent and very effective.”