Malaria mosquito hunt by satellite

Fight against malaria: hunting mosquitoes via satellite

09/13/2014

Every year, malaria requires hundreds of thousands of lives, especially in Africa. Researchers in Heidelberg now want to score points in the fight against tropical diseases with a new method. These include satellite image maps as well as a technology with which mosquitoes are successfully fought on the Rhine.

Dangerous diseases in Africa
The news reports daily about the dramatic development of the Ebola epidemic that is rampant in West Africa. The deadly disease almost makes you forget that there are other dangerous infectious diseases in Africa, such as malaria. This is one of the most dangerous tropical diseases. „Every year, 600,000 people die of this preventable and treatable disease“, Renate Bähr, Managing Director of the World Population Foundation, said in Hannover in April. However, a few years ago, researchers in the US used computer models to calculate significantly higher deaths from malaria infection. They had about 1.2 million deaths, almost twice as many as the World Health Organization (WHO) had stated in the past.

„Killer number one“
Even if the numbers are not clear, it is clear: „Malaria is the number one killer in Africa.“ This said the biologist Norbert Becker from Speyer a dpa report, according to the disease, which is transmitted by mosquitoes. More than 90 percent of the dead are in Africa, according to experts, "the majority of them children under five". Becker is part of a Heidelberg team of scientists that wants to tackle the mosquitoes and malaria with a new strategy that also uses satellite imagery.

Mosquito larvae reduction by up to 98 percent
Currently a practical test is being run in Burkina Faso. „The ultimate goal we want to achieve is to reduce malaria-related deaths“, explained Project Manager Peter Dambach. The project is according to his statements unique in this form. Becker is the scientific director of the Municipal Action Group for the Control of Snaring Plague (Kabs), which includes 99 communities on the Upper Rhine. On their behalf, the 65-year-old and his team have been fighting mosquito larvae for almost four decades, which hatch after flood waves on the Rhine. For this they use a bacterium (Bacillus thuringiensis israelensis, short: Bti), which according to Beckers kills only the larvae of mosquitoes, but has no effect on other creatures. He explained: „We have a reduction of up to 98 percent.“

„Safe for people and the environment“
The driving force behind the Bti mission in Africa is the Heidelberg physician Rainer Sauerborn, who has long been familiar with the situation in Burkina Faso. Already last year, he said that the project is the successful transfer of a technology that has been used extensively and routinely along the Rhine for many years. The method was very effective, safe and harmless for humans and the environment. The existing malaria control program had brought only limited success. Among other things, one puts emphasis on "impregnated nets over the beds, but which are not used nationwide and only provide protection during the night".

Use funds effectively
„That's why we said: fighting larvae can be cheaper and more effective“, Becker. The foundation of the entrepreneur Manfred Lautenschläger supports the project with 400,000 euros. Overall, the scientists in Burkina Faso have 127 municipalities with around 150,000 inhabitants in view. Of these, in one third only bednets are being used as mosquito repellent, in another one all brood waters will be treated with Bti and in the third sector the new strategy will be tested: Bti will only be used where more larvae are found in the water. This is because many African countries are poor and it is therefore important to use the funds effectively, as Geograf Dambach, who has a doctorate in public health at Sauerborn, explained.

Method as on the Rhine
With the help of satellite maps the mosquito repeaters find the relevant places. These map the different types of water and thus help to find the preferred breeding sites. „Larvae have certain preferences when it comes to water“, so Dambach. The larvae of the malaria-transmitting mosquito only like clean water in which there are plants. Turbidity, coloration and nutrient availability of the water decide how suitable it is for mosquitoes. Dambach explained that you can find on the satellite images of the region all ponds that had the same water parameters. One could conclude from these parameters that the density is high there - and use the Bti. As on the Rhine, it is deployed by teams with portable syringes every ten days. He further explained that Bti is also used in projects in Ethiopia and Kenya, but it is not working with satellite imagery. The risk mapping process was developed in a precursor project in which the University of Heidelberg was in charge.

Mosquito and stitch numbers dropped significantly
The villages are eager to measure and compare to find out "which method is most successful". So will be examined, "how high the mosquito burden and thus the risk of transmission and how malaria is in children". According to Dambach, there is a question at the end: „Do we have an effect on disease and mortality?“ It does not use anything if only the number of larvae sinks. Final results are not available yet. The study, which follows the first survey phase without Bti from 2013, runs until 2015. Dambach reported that many villages reported that mosquito and stinging numbers had already dropped significantly. „The people are excited.“ The expert Egbert Tannich from the Bernhard Nocht Institute for Tropical Medicine in Hamburg also speaks of an interesting approach. Looking at the use of satellite imagery and Bti, he said: „I do not know any investigation that has ever been done.“ (Ad)