World Health Organisation backs use of DDT against malaria

The World Health Organisation (WHO) has endorsed the use of banned insecticide DDT in a new approach to controlling malaria in West Africa. Stephan Tohon, WHO’s focal point on malaria in West Africa, told a malaria evaluation meeting in the Burkina Faso capital Ouagadougou that the organisation no longer recommended the use of mosquito nets. Instead he cited the positive results of southern African countries with indoor house spraying using the partially banned insecticide DDT.

The endorsement of DDT (Dichloro-Diphenyl-Trichloroethane) will be particularly controversial. The pesticide was used in World War II to control malaria with apparent great success. DDT is toxic and kills by opening sodium ion channels in insect neurons, causing the neuron to fire spontaneously. The Swiss chemist Paul Müller won the Nobel Prize for medicine in 1948 for demonstrating DDT killed the Colorado potato beetle, a pest that was ravaging the potato crops in the developed world.

DDT contributed to the final eradication of malaria in Europe and North America and WHO’s program to combat malaria worldwide was based on the success of the drug. DDT was less successful in the tropics. Because farmers used it as a crop spray, insect populations began to develop resistance. It all began to unravel for DDT in 1962 when Rachel Carson published the hugely influential “Silent Spring” which showed the chemical resulted in reproductive problems and death in humans. The US eventually banned DDT in 1972.

With the failure of DDT, experts focussed their attentions on bednets impregnated with other insecticides. However the Stockholm Convention of 2001 which outlawed a dozen persistent organic pollutants left the door open for continued use of DDT as a vector control. Vector control works by reducing the levels of transmission and its method varies widely depending on local conditions.

Arata Kochi, head of the WHO's antimalarial campaign, is leading the charge to bring back DDT. In November 2006 he called on environmental groups to support the change. “We are asking these environmental groups to join the fight to save the lives of babies in Africa," Kochi said. "This is our call to them." Kochi is supported a group called Africa Fighting Malaria, who say that while there may be lab studies showing DDT could potentially cause cancer, no large studies show an actual increase in cancer in people.

While the jury remains out on DDT, there is no denying that malaria is one of the world’s greatest health problems. Approximately 40 percent of the world’s population, mostly in the poorest countries, are at risk of contracting malaria. Its intensity depends on local factors such as rainfall patterns, proximity of mosquito breeding sites and mosquito species. Every year, an astonishing 500 million people (one person in every twelve) become seriously ill with one of the four different types of the disease.

Malaria has serious economic impacts in Africa, slowing growth and development as well as perpetuating a vicious cycle of poverty. It mainly afflicts the poor who tend to live in malaria-prone rural areas in poorly-constructed houses with few barriers against mosquitoes. Malaria disease affects sub-Saharan Africa harder than anywhere else in the world and kills about 800,000 children younger than 5 each year. The disease also contributes greatly to anaemia among children, a major cause of poor growth and development. Malaria infection during pregnancy is associated with severe anaemia and other illness in the mother and contributes to low birth weight among newborn infants.

The cause of malaria is a parasite called Plasmodium, transmitted through bites from infected mosquitoes. In the human body, the parasites multiply in the liver, and infect red blood cells. Symptoms include fever, headache, and vomiting, usually about 10 to 15 days after the mosquito bite. If untreated, Malaria can kill by disrupting the blood supply to vital organs. The parasites have developed resistance to a number of malaria medicines and the field of malaria control has historically been dogged by problems with resistance. Each time scientists find a way to fight the parasite, the parasite finds a way to fight back. WHO says resistance can be limited if DDT is used carefully, and only where it's likely to be effective.

Chikungunya reunion

Malaria remains a scourge of much of the developing world. It kills somewhere between one and five million people a year. Only pneumonia and AIDS kill more people outside the Western World. The World Health Organisation believes that 300 million are infected annually. Closer to the ground, the Kenyan Medical Research Institute says there are actually 515 million cases a year of the deadliest form of malaria alone.

But now some of malaria’s lesser known cousins are now starting to share the limelight. One of the most virulent at the moment is from a bite by Aedes aegypti. Better known in English as the Yellow Fever Mosquito, Aedes aegypti is a tolerable host to a number of fevers that are dangerous to humans. As well as the yellow fever itself, it is home to dengue fever and a new, previously non-fatal disease that is now killing people in the South. It is called chikungunya (“chicken gunya”) Chikungunya is Makonde (a Tanzanian language similar to Swahili) for ‘that which bends up.’ People struck by the disease end up with a hunched back and intense pain.

Chikungunya was never considered fatal, until recently. Acute chikungunya fever typically lasts a few days to a couple of weeks, but similar to other fevers, it can have prolonged fatigue lasting several weeks. One million people a year are infected with chikungunya which is minute compared to malaria. But its recent change of behaviour is cause for alarm. Now it is starting to kill.

On the island of Reunion, an outre-mer department of France in the Indian Ocean chikungunya has killed 315 people since it broke out in March 2005. The French occupied the island in the 17th century and the name Reunion commemorates the union of French revolutionaries from Marseille with the National Guard in Paris in 1792. It is now a busy country with 775,000 people crammed into its two and half thousand square kilometres. It is the 4th densest department of France and only Paris, Martinique and Calais have more feet per foot. Chikungunya was first noticed on Reunion in February 2005. Barely one year later, 50,000 people on the island were infected.

Now over ten percent of the population has Chikungunya. There is a twenty four hour mission every day to spray insecticide with the French Army involved by day and volunteers by night. In the country they are looking for mosquito larvae anywhere they can find standing water. But chikungunya is winning the battle. By March, a local French newspaper reported there was 186,000 cases - a quarter of the island.

Chikungunya started to crop up in other Indian Ocean islands. It moved around from Madagascar and the Comoros, to Mayotte and the Seychelles. Across the islands chikungunya has infected more than 1.3 million people in the last 20 months. By 24 November, half a dozen US states have reported cases of travellers from Asia and East Africa returning to the States with the virus.

One day later, a Sri Lanka health official confirmed the epidemic arrived in the country. Dr Nihal Abeysinghe, director of the state epidemiology department, says it has infected 5 000 people in the island's Tamil controlled far north. The people of Tamil capital Jaffna residents are living on rations shipped in by sea. Medicines and food are in short supply. Local residents said doctors had recommended paracetamol as a fever preventive, but most shops had run out. On the same day, Taiwan reported its first ever case.

No vaccine or specific antiviral treatment for chikungunya fever is available. Unconfirmed reports have stated the US military has a vaccine as of March 2006. But if they have it, they aren’t sharing. The last known trials were in 2000 but were discontinued due to lack of funding. Meanwhile on Reunion, the pain goes on. Islander Louise Maillot has been suffering from intense pain in her legs and depression since chikungunya struck. I'm waiting to die," she told Al Jazeera. "I'm praying for the good Lord to take me."