Floating spores kill malaria mosquito larvae

The parasite (genus Plasmodium), which causes malaria, is transmitted to humans with mosquito saliva during a bite, where it invades the liver and red blood cells causing fever. Once infected, it can be difficult for a human host to recover because some species of Plasmodium are able to lie dormant and evade antimalarial drugs. These parasites are also becoming resistant to the antimalarials taken to prevent infection. An alternative way of reducing the risk of malaria infection is to kill the mosquitoes. The fungi, M. anisopliae and B. bassiana, cause muscardine disease in mosquito larvae, leading to their death before they can pupate and develop into the adult form.

Tullu Bukhari and colleagues from the Laboratory of Entomology, Wageningen University, The Netherlands, have used a synthetic oil (ShellSol T) as a means of dispersing fungal spores over the surface of water. The oil-spore preparation is easy to mix and use of the oil improved the dispersal of spores across the water. This simple formulation increased both the persistence and effectiveness of spores, killing up to 50% more larvae than untreated spores and reducing pupation levels to less than 20% at a test site in Kenya.

Speaking about the research Tullu Bukhari said, "these fungi provide an effective means of controlling malaria mosquitoes. Both spores and the oil have minimal risk to fish and aquatic organisms and so are also environmentally safe."

More information: Development of Metarhizium anisopliae and Beauveria bassiana formulations for control of malaria mosquito larvae, Tullu Bukhari, Willem Takken, and Constantianus J.M. Koenraadt, Parasites and Vectors (in press)

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