Stopping Malaria with a Sugared Mousetrap

When I was an active clinician I saw several people die of malaria and it’s one of those things that you don’t forget. Nobody likes losing a patient, particularly to a potentially preventable disease. I would often think of the millions of people infected by this parasite. There are 300 million clinical cases of malaria each year, and around the world over one million people die of the illness each year. It has been calculated that a child dies of malaria every 30 seconds, with the largest number of deaths occur among young children in Africa.

We know that cleaning up water supplies and appropriate insecticides would make a huge dent in that terrible clinical toll, and hats off to the Bill and Melinda Gates Foundation for its massive attempts to do things that make sense for helping eradicate malaria and a score of other problems.

There are academics and some pharmaceutical companies that are working on malaria vaccines, and I wish them well. But I wonder about the practicality of paying for vaccines for hundreds of millions of people, when for a fraction of the cost, clean water would do a much better job, and without all the potential problems that might be associated with vaccination.

Global climate change will likely make the range of malaria-carrying mosquitoes much greater in the years to come: it was recently suggested that malaria might in our lifetimes spread as far North as England.

I was very interested to read of an entirely new approach to targeting malaria that could be cheap and easy. It’s also so obvious that I’m sure that there are scientists the world over who are slapping their foreheads this weekend.

I a study reported in the International Journal for Parasitology a team from Hebrew University was able to devastate a local mosquito population by spraying acacia trees with a sugar solution spiked with an insecticide.

The Plasmodium parasites that cause malaria are spread by female Anopheles mosquitoes. The female mosquitoes need blood to develop their eggs, but they also need large amounts of sugar to support their metabolism, so they need large amounts of sweet plant nectar.

What the Israeli team did was to spray acacia trees in an oasis in Southern Israel with a sugar solution containing the insecticide Spinosad. This area was chosen because there were few other plants from which the mosquitoes could obtain sugar. After spraying, the mosquito population was decimated.

Clearly this technique is going to be most valuable in areas with limited plant growth, so the mosquitoes aren’t just going to be able to go next door for food. Though that being said, Anopheles mosquitoes are fussy eaters and only visit a limited number of plant species. So now one suggestion is to plant mosquito attracting plants and spraying them with insecticide. Naturally enough, one worry is that the mosquitoes will learn to go to plant sources that they normally wouldn’t touch, or that they will develop resistance to the pesticides. And though Spinosad is supposed to be an environmentally friendly insecticide that doesn’t effect other insects, birds or animals, we have to keep an eye on the possibility that it may not be all that benign.

This work is going to need to be replicated, but it is an encouraging new approach to a horrible illness that is second only to tuberculosis in the number of people that it kills each year.