BANGOR, Maine (WABI) - Did you know that malaria is the infectious disease responsible for the most deaths in the history of our species? Although smallpox and tuberculosis (TB) are close rivals, epidemiologists at the World Health Organization estimates that malaria comes out on top due to the fact that that it is still claiming 1.2 million lives per year while smallpox was stopped by vaccination and TB can be treated with antibiotics. During World War II alone, more than 60,000 US soldiers died from this disease contracted during the African and Asian campaigns. To put it in perspective, this was greater than the number of US soldiers killed in combat during the entire first world war. Although here in temperate climates mosquitoes are an itchy nuisance that can disrupt an outdoor picnic, in tropical and subtropical parts of Africa, Asia, and South America they remain a deadly threat.
That is why public health advocates the world over were very impressed with a recent study reported in the May 31st issue of the journal 'Science' in which researchers from the University of Maryland described a fascinating new approach to this ancient scourge*. They reported on a successful genetic manipulation of a common fungus that is a natural pathogen for mosquitoes. First, they isolated a gene from an Australian genus of spiders known to produce a venom that is deadly for insects. Next, they inserted that gene into the fungus that afflicts the mosquitoes. Then, when they exposed this genetically altered fungus to malaria carrying mosquitoes, they achieved a 99% kill rate. And what is most impressive about this approach is that there are no known risks to other insects, mammals or predators such as birds that could consume these afflicted mosquitoes. This fungus is so specific for its host mosquito, it does not infect other species -- which is good news for potentially helpful insects such as honeybees.
While further studies to rule out any adverse environmental or human risks are being carried out in the African nation of Burkina Faso, there is good reason to be very optimistic. Currently, many who live in regions where malaria is endemic need to take daily precautions to avoid infection. Insecticides are commonly sprayed both outside and even inside homes. Topical repellents that contain DEET need to be applied frequently. Outdoor activity after dark should be very limited, and insecticide impregnated nets should be hung over the bed. Travelers may benefit from taking daily medications (which can have significant side-effects) to prevent infection. If this new research provides another tool in our black bag to combat this deadly disease, large parts of the world could become much safer for human habitation – and that would be a good thing!
*Lovett, Bilgo, et al. Science, 2019; 364 (6443): DOI: 10.1126/Science. aaw 8737