Mozzies beware!

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Swatting adult mosquitoes may give a certain amount of emotional satisfaction, particularly if they are females that have just bitten you, but it is much more effective to kill their young.

Once again, mosquito-borne disease is on the increase: not only malaria, which affects hundreds of millions of people per year and kills several millions, but also virus diseases, such as dengue. Even the USA can suffer; recently there was an outbreak of encephalitis in New York, caused by a virus transmitted by mosquitoes from birds to humans. Global warming will add to the problems.

Usually, mosquito populations are limited by the capacity of the aquatic habitats of their larvae so these offer the best opportunity for control. Certain bacteria produce toxins which kill the larvae but getting them into the right place at the right time is difficult, particularly as some of the most dangerous mosquitoes make use of the sort of temporary puddles provided, for example, by hoofprints.

Now, Dr Neil Crickmore of BIOLS has been awarded a grant by the Wellcome Trust to pioneer an alternative approach. His aim is to develop transgenic bacteria, using bacteria from mosquito-infested waters (or from mosquitoes themselves), which interact naturally with mosquito larvae and can be propagated cheaply. Normally these bacteria are harmless to mosquitoes, but the aim is to induce them to produce the toxins associated with the mosquito-killing bacteria. Another main task will be to ensure the genetic stability and safety to the environment of these genetically modified organisms.

The research will be orientated towards disease problems in South America but promises much wider application.