A professor from the University of Queensland in Australia has had marked preliminary success in using “virus-blocking bacteria” to reduce the population of dengue-fever-carrying mosquitoes. Scott O’Neill released mosquitoes infected with a strain of the bacteria, Wolbachia, into residential areas (with homeowners’ permission) in January and February 2011. Ars Technica dubs this Wolbachia strain a “gonad-chomping parasite”:
[W]hen infected males mate with uninfected females, all their offspring die. When they mate with infected females, the offspring survive, but all carry a Wolbachia infection. This helps ensure that the bacteria spread quickly within a population.
O’Neill’s experiment was a success: “In just five months, the bacteria had swept through virtually the entire A.aegypti population,” says Discover’s Not Exactly Rocket Science.
There are, of course, caveats: Dengue could conceivably mutate in response to such manipulation, and it’s impossible to predict whether the new form could be more dangerous. O’Neill will be carrying on his research by heading to Vietnam, where dengue is persistently present, unlike Australia, where there are unpredictable outbreaks.
This isn’t the first experiment in turning mosquitoes against themselves. At the beginning of the year, Malaysia released genetically engineered male mosquitoes into unpopulated forest areas. When the genetically modified bugs mated with females in the wild, the offspring either died or lived shortened lives.
Dengue is primarily found in tropical countries and infects as many as 50 million each year, according to the World Health Organization. Dengue prevention efforts include spraying to kill mosquitoes and eliminating standing water where mosquitoes can breed, but the disease has become more, not less, prevalent over the last few decades.