Dengue fever is a nasty disease found all over the tropics, with names like break-bone fever referring to the severity of the pain it causes. It is carried mostly by the mosquito Aedes aegypti, but also by related species. I have just read three reports on the BBC science site of techniques aimed at controlling the fever by attacking the mosquito in its sex life.
In the first of these Global award for dengue control Oxitec, an Oxford based company, are applying the classic “sterile male” technique to stop them breeding. This was first used against screw worms, maggots which eat into the flesh of livestock and sometimes even humans. The “traditional” method employs radiation to sterilize the males, such as the “sterile atomic fly” to combat sleeping sickness. Oxitec, however, are using genetics and molecular biology.
In the second ‘Bug’ could combat dengue fever Wolbachia bacteria are employed. These are transmitted heritably down the mosquito generations; the interaction of these with the sex lives of insects is related in an interesting Wikipedia article. In Australia a Wolbachia strain has been developed which shortens the mosquito’s life so that the dengue virus does not have time to incubate, since only older insects infect humans. This work appears in the first 2009 issue of Science.
In the third Mosquitoes make sweet love music a team from Cornell University are targeting the mosquitoes by interfering with their love songs. According to the BBC article, the amorous couple began to beat their wings together at a matching frequency – 1,200 hertz, which is a harmonic, or multiple, of their individual frequencies – 400 Hz for the female and 600 Hz for the male. I don’t yet have access to the original article which has only just appeared in Science, so I’m not sure whether they actually beat their wings at the higher frequency or whether the harmonics are generated by some kind of resonance. One avenue the Cornell researchers are looking at is the possibility of genetically engineering sterile males that are better singers. (Not to be confused with operatic Castrati).
