“Bed nets saved money used for Malaria treatment. Now we can spend it on our children's education.”
- Helen Kyalimpa, Mother, Kenya
Nets against the most dangerous tropical disease in the world
Malaria is still the most dangerous tropical disease today. An estimate of the exact number of cases is almost impossible – but according to the 2013 World Malaria Report up to 207 million people suffer from the disease, and up to 650,000 die each year. It also causes economic calamity in the affected countries: the disease reduces the labor force – especially in rural areas where the people are particularly exposed to the carrier mosquitoes – and threatens the population's ability to support itself independently. Affected families have an additional burden to bear because they have to pay the costs of treatment out of scarce resources. Children under the age of 5 are especially at risk, and older children are often unable to go to school. Protection against the disease, therefore, also means an investment in educating the children.
Impregnated mosquito nets reduce the risk of infection
It remains difficult to contain the disease, since the adaptable pathogens quickly develop a resistance to therapies, and the mosquitos have also become resistant to the insecticides used. This is especially tragic, since bed nets are an effective protection against infected Anopheles mosquitoes, especially if their effect is further enhanced by being impregnated with insecticides. When properly used, such nets reduce the risk of infection by up to 50 percent. The WHO uses high-quality nets that do not lose their effectiveness even after 20 washes. About 150 million new nets a year are needed in Africa to maintain a virtually comprehensive supply.
Bayer CropScience is involved in several projects in the fight against malaria. Among other things, the company campaigns to supply the at-risk population with impregnated bed nets.
Providing lasting protection in net manufacture
For more than ten years, Bayer has been delivering three insecticide formulations (K-O TAB®, K-O TAB 123 and K-Othrine® moustiquaire), and up to now it has been the finished mosquito nets that have been impregnated with the insecticides. Now Bayer has developed a process in which the fibers are already impregnated during the manufacturing process. The new nets (LifeNet®) are made of soft, highly tear-resistant polypropylene and are wash-resistant for more than 30 washes, providing lasting protection for up to five years when used properly. LifeNet has been evaluated by the WHO and is being launched on the market.
A second way of controlling the carrier mosquitoes is to spray the interiors of people's homes with insecticides that have a long-term effect (indoor residual spraying, IRS). Unfortunately, here, too, forms of resistance are beginning to develop against pyrethroids, the most commonly used class of active substance. However, Bayer is able to use its active ingredients to offer a rotation system with several non-cross-resistant insecticides. This makes it possible to control existing forms of resistance and prevent new ones from developing.
New drugs against resistant malaria carriers
Bayer is furthermore researching and investing in new ways of combating malaria mosquitoes that are resistant to the insecticides currently in use. Since 2009 Bayer and the Innovative Vector Control Consortium (IVCC) have been working together on new resistance-breaking agents. By screening the compound library at Bayer CropScience – one of the largest in the world – the researchers have identified four suitable chemical substances that are now being further developed by chemists. Furthermore, insecticides that are used in agriculture, etc., are being tested to determine their efficacy against mosquitoes. Here, too, suitable approaches are already undergoing final tests. A success of these two-pronged efforts would be a sensation for the people in the malaria-affected areas, as well as for science. The last time new mechanisms of action were developed against malaria mosquitoes was 60 years ago, and the last new drug was approved 20 years ago.
Number of cases worldwide: 207 million (between 135 and 287 million), mainly in Africa
Transmission: Plasmodium parasites are transmitted to humans by the bite of the Anopheles mosquito.
Course of the disease: If left untreated, severe malaria (infection with Plasmodium falciparum) is fatal, since the disease disrupts the supply of blood to the organs. The most vulnerable population groups are children under five and pregnant women. In most cases, malaria can be effectively treated with an artemisinin-based combination therapy
The main things that need to be done: Supply the affected population with drugs; launch prophylactic measure in all affected areas by supplying the population with durable, impregnated mosquito nets and explaining how to use them properly; develop new active substances against resistant pathogens and carriers.