columnBy Chris White
Nairobi — The World Health Organisation's new stance on DDT, yet again only goes to show how so many in the West throw out opinions without really understanding the context or culture of Africa. The WHO recently forcefully endorsed wider use of the insecticide across Africa to exterminate and repel the mosquitoes that carry malaria. Currently, the disease needlessly kills more than a million people a year, 800,000 of them young children in Africa.
Dr Arata Kochi, director of the WHO malaria programme, has announced that DDT is the most effective insecticide against malaria. However, those of us in Africa have to think logically and realistically about the socio-economic context in which we work. The first question is whether or not Indoor Residual Spraying (IRS) is better than the widespread use of insecticide-treated nets.
For effective control of mosquitoes, at least 80 per cent of all households must be covered every 6-12 months by well-coordinated spray teams. Is this possible in Africa? Imagine trying that across the Congo basin! It is not realistic to assume that this will happen. It will just leave the communities vulnerable again.
But now imagine every family in Africa having a net. Nets last four to five years and can be carried around by everyone, including internally displaced people and nomadic groups.
The distribution of nets in a one-off large-scale vaccination campaign is less challenging than trying to reach 80 per cent of all households with a veritable army of spray teams every 12 months.
Like the WHO, Amref supports the continued use of DDT as a means to control malaria, but only in areas where it is cost-effective and possible to spray on a regular basis. This is one of the reasons spraying is primarily suited to the unstable transmission areas like the Kenyan highlands or the Afar region of Ethiopia.
These are known as unstable transmission areas because malaria only poses a risk to a small group of people for a short time of the year. Here, malaria is containable and localised, and spraying can be done every six to 12 months.
Compare that with trying to spray a country the size of the Democratic Republic of the Congo, which battles with malaria 365 days a year, has a civil war raging, is largely a rainforest, and has little infrastructure to get to isolated communities. It is much easier to deliver insecticide-treated bed nets every four or five years.
Those who have managed spraying campaigns know that it is very difficult, much like a full-scale military exercise. The new WHO statement is misleading and operationally unsound.
South Africa is often cited as a prime example of the benefit of DDT use, but this is not entirely true. The country has very little incidence of malaria in the first place. Transmission is largely seasonal and restricted to a tiny belt in the north east.
Also, there is good infrastructure and a reasonably well financed Ministry of Health. It would NOT be easy to control malaria by spraying across most of sub-Saharan Africa.
The Roll Back Malaria working group is putting together a review on the relative merits of spraying versus bed nets. I only hope that when it finally becomes available, the politicians and lawyers leading this pointless and harmful debate will learn something.
Chris White is the Malaria Programme Leader with the African Medical and Research Foundation