Fungus enhances susceptibility of resistant malaria mosquito to pesticides
Malaria mosquitoes are becoming increasingly resistant to pesticides. As a result, malaria is difficult to control. In addition to the existing chemical pesticides such as DDT and pyrethroids, which are applied in the interior and bed nets, there are few options for mosquito control. The use of insects, fungi, murder is a new method of biological control of malaria mosquitoes that developed in 2005 in cooperation with researchers at Wageningen. The spores of fungi can infect and kill mosquitoes on contact in a few days. Moreover, a fungal infection of the mosquito reduces appetite and slows the development of malaria parasites inside the mosquito.
Together with colleagues from South Africa, Wageningen researcher Marit Farenhorst these fungi tested for the first time in several mosquito species of pesticide resistant malaria. In the laboratory, in Johannesburg, the research team compared the effectiveness of the fungi in mosquitoes that are susceptible to insecticides and their families who are resistant. The fungus Beauveria bassiana was able to kill the mosquitoes susceptible and resistant malaria. This indicates that the malarial mosquitoes that are resistant to pesticides are not resistant to the fungus.
In addition, the team studied to what extent that mosquitoes are infected with the fungus are also susceptible to pesticides. To this end, the resistant mosquitoes were infected with spores of the fungus Beauveria bassiana and Metarhizium anisopliae. After three days of incubation, which were analyzed for resistance to permethrin and DDT pesticides. Both species of fungi increased susceptibility of mosquitoes to these agents, more mosquitoes died after exposure to chemicals when they were infected with the fungus. The researchers believe that toxins secreted by fungi weaken the mechanism of the mosquitoes’ resistance.
The results show the potential of fungi as an effective and sustainable biological control agent of mosquitoes of malaria. Due to the increasing problem of resistance to pesticides in Africa, offering a vital alternative to current control methods.
Because infected mosquitoes die slowly, over a period of several days, they are still able to reproduce. As a result, there are far fewer opportunities for their children to become resistant to fungi. According to investigators, the relatively slow effect of mushrooms is enough to block transmission of malaria. On average, it takes 10-14 days before a mosquito that has acquired malaria parasite during a blood meal can transmit the disease to another person. “In fact, only killing the” old “mosquitoes, and these are really the most dangerous,” explains researcher Bart Knols.
Because fungi to improve the effectiveness of pesticide-resistant mosquito, researchers see a mushroom combination of pesticides as an important addition to the limited arsenal of anti-malaria weapons.
Worldwide, more than one million people die each year from malaria, mainly African children under age five and pregnant women. More than 3 million people live in areas where there is a risk of malaria infection, and each year more than 500 million people suffer from an infection. The disease is transmitted by mosquitoes, and mosquito control is performed with mosquito nets are treated with a pesticide or pesticide application through to the interior walls.
The resistance to conventional agents used to control mosquitoes, mainly the so-called resistance to pyrethroids used for impregnated bednets, is becoming increasingly widespread, particularly in West Africa. In some countries such as Benin, insecticide-treated nets and indoor spraying and not offer enough protection. Over the past 20 years, no chemical alternative has appeared on the market, and the potential for biological control of mosquitoes (fungi) is seen as a sustainable alternative to avoid resistance.
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