All the chemicals that human beings use to kill living things (weeds, bacteria, viruses) are subject to the same basic problem of resistance. A chemical that doesn’t manage to kill a few individuals will leave them with a huge opportunity to reproduce without competition. As such, all pesticides, herbicides, and antibiotics are likely to become less effective with time. Andrew Read, a Professor of Biology and Entomology at Penn State, is working on an approach for controlling malaria that circumvents this difficulty.
The mosquitoes that spread malaria are not born with the disease. Rather, they must bite someone who is infected. It then takes 10-14 days for the parasites to develop in the female mosquitoes, after which they reach the salivary glands and the insect becomes infectious. Read’s idea is to create a fungus that becomes lethal to mosquitoes after 10-12 days. As such, the fungus would exclusively kill the type of mosquitoes that infect people with malaria. The brilliant aspect of this is that the females will already have reproduced before being killed. That makes it far more difficult for genes resistant to the fungus to emerge and proliferate within the gene pool. That could make it an especially valuable tool in the fight against malaria – an illness that kills about one million people a year.
The idea is similar in some ways to the insect killing fungi described in Paul Stamets’ book, though his colony-exterminating approach seems like it would eventually breed resistance in a way that killing only older female mosquitoes would hopefully not do.
This fungus idea is very clever, and seems like it could contribute in a significant way to fighting malaria.
Do you know anything about how the fungus would be introduced into mosquito populations? What about how it will spread between the animals?
According to the linked webpage, they are using a “novel pathogen delivery system infecting resting mosquitoes via residual pick-up of spores from surfaces treated with the oil-based formulation.”
This seems similar to Stamets’ suggestion that chainsaw oils laden with appropriate spores could speed up the decomposition of unwanted parts of logged trees.
It doesn’t say anything about insect-to-insect transmission.
Consider Polysphincta gutfreundi, a parasitic wasp that grabs hold of an orb spider and attaches a tiny egg to its belly. A wormlike larva emerges from the egg, and then releases chemicals that prompt the spider to abandon weaving its familiar spiral web and instead spin its silk thread into a special pattern that will hold the cocoon in which the larva matures. The “possessed” spider even crochets a specific geometric design in the net, camouflaging the cocoon from the wasp’s predators.
Scientists have discovered a microbe that completely protects mosquitoes from being infected with malaria.
The team in Kenya and the UK say the finding has “enormous potential” to control the disease.
Malaria is spread by the bite of infected mosquitoes, so protecting them could in turn protect people.
The researchers are now investigating whether they can release infected mosquitoes into the wild, or use spores to suppress the disease.