| Jasper Rothfels |
HEIDELBERG, Germany (dpa) – Africa’s Ebola crisis has taken the spotlight off other diseases plaguing the continent, such as malaria.This mosquito-borne parasite claims a million lives across the globe each year, more than 90 per cent of them in Africa.
“Malaria is Africa’s number-one killer,” says Norbert Becker. The biologist based in south-western Germany is part of a team of scientists centred in the university city of Heidelberg working on a new strategy to counter the disease using satellite images.
A trial is currently running in Burkina Faso in West Africa.
“Our ultimate objective is cut the number of malaria-related deaths,” project leader Peter Dambach says.
Dr Becker, 65, is scientific director of a campaign to combat midges and mosquitoes along the River Rhine in Germany. That campaign, code-named Kabs, has been active for almost 40 years.
His team makes use of a bacterium (Bacillus thuringiensis israelensis- Bti) to kill the mosquito larvae, while leaving other forms of life unaffected. “We achieve reduction rates of up to 98 per cent,” he says.
Mosquito larvae grow to maturity in puddles and pools. Rhine mosquitoes are not malarial, but used to be a major nuisance.
Bti is now being tested in Africa under Rainer Sauerborn, a Heidelberg-based professor specialising in tropical diseases who is well acquainted with conditions in Burkina Faso.
Efforts to combat the disease have thus far had only limited results.
One of the mainstays is putting pesticide-impregnated nets over beds, but they are not used everywhere and in any case offer protection only at night.
“So we said that combating the larvae could be cheaper and more effective,” Becker says. The team is focusing on 127 villages that are home to around 150,000 people.
In a third of them, bed nets only are being used, as previously. In another third, all potential breeding grounds are being treated with Bti. In the last third, Bti is being used selectively only on ponds where large numbers of mosquito larva have been found.
The last is a new tactic. Since African countries are poor, and scant resources need to be deployed to best effect, selective spraying would save money and might turn out to be sufficient to stop malaria.
The mosquito hunters find their quarry by means of satellite images showing all the different water surfaces in a region, pointing to the range of options where mosquitoes might be breeding.
“Larvae have certain preferences, as far as water is concerned,” says Dambach, 36, who studied under Sauerborn.
The larva that turn into mosquito-bearing mosquitoes likes clean water with plant life. The cloudiness, colour and nutrient content of the water all go to deciding what is most attractive for the mosquitoes.
The satellite images of the region can be used to identify all the pools showing the same characteristics, on the basis of a preliminary project conducted under the leadership of Heidelberg University, Dambach says.
Using these parameters, a conclusion can be reached about where the arva density will be greatest and Bti can be sprayed there as apriority.
The killer bacteria are spread every 10 days by teams using portables praying equipment. Bti is also being used in projects in Ethiopia and Kenya, but without the benefit of satellite imaging.
Careful readings are taken in the villages to assess which method is the most effective. Mosquito infestation, transmission risk and the incidence of malaria in children are all evaluated.
Ultimately the question for Dambach is: “Are we having an effect on disease and death rates?” Merely cutting larva infestation is no use.
There are as yet no final conclusions, as the investigation is still running. But there are reports from the villages that the numbers of mosquitoes and mosquito bites have declined considerably, according to Dambach.
“The locals are happy,” he says.