BBC Homepage World Service Education
BBC Homepagelow graphics version | feedback | help
BBC News Online
 You are in: Sci/Tech
Front Page 
UK Politics 
Talking Point 
In Depth 
Friday, 30 June, 2000, 09:48 GMT 10:48 UK
Infected flies boost malaria hope
The fruit fly is the most studied insect on Earth
Researchers have managed to infect the fruit fly with the parasite that causes malaria.

The achievement could make it easier to develop new drugs and vaccines to combat the disease which is spread by the parasite's usual host, the mosquito.

Fruit flies are a geneticist's best friend

Dr David Schneider
Scientists know more about the fruit fly than any other insect, having recently decoded its entire genome.

They hope their "surrogate mosquito" will help them better understand how insect hosts interact with the parasite to yield new ways of fighting infection.

Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths globally each year. Ninety per cent of all malaria cases are in sub-Saharan Africa where it is the main cause of death and a major threat to child health. Worldwide, a child dies of malaria every 30 seconds.

Different life stages

Nevertheless, scientists know very little about how mosquitoes carry the disease and transmit it from person to person, largely because the insects are difficult to handle in the laboratory.

"Fruit flies, on the other hand, are a geneticist's best friend," says Dr David Schneider, from the Whitehead Institute, Massachusetts, US, which has been part of the research to produce the parasite-carrying fruit fly.

"There are many genetic markers, we can conduct genetic screens simply and in large numbers, and we now have the complete sequence of the fly genome."

The malaria parasite, Plasmodium, cycles between humans and mosquitoes to spread through a population.

When the mosquito bites an infected person and ingests the parasites present in the blood, a complex process takes place that sees Plasmodium pass through several different life stages before it is released into the blood of another person when the mosquito bites again.

Corresponding genes

"Plasmodium is not a simple organism like a bacterium or virus," says Dr Mohammed Shahabuddin, at the US National Institute of Allergy and Infectious Diseases and a co-author on the study published in the journal Science.

"It has multiple developmental forms, each of which is distinct from the other. One form causes disease in humans, another is swallowed by mosquitoes, still another form reproduces, others move through the insect's intestines, and yet another enters the salivary gland of the mosquito and infects people."

Studying how the parasite interacts with its insect host is difficult, he said, because the mosquito's biochemical and genetic make-up are not well defined.

The fruit fly, (Drosophila melanogaster), on the other hand, does not have this problem.

"Our ability to grow Plasmodium in the fruit fly is especially fortunate because scientists recently determined the complete sequence of the Drosophila genome," says Dr Shahabuddin. "So now we can scan the entire genome and identify the specific genes involved in the fruit fly's response to Plasmodium, and then look for the corresponding genes in the mosquito."

This will hopefully reveal new targets for novel drugs.

Search BBC News Online

Advanced search options
Launch console
See also:

23 Mar 00 | Sci/Tech
Small fly makes history
02 Nov 99 | Sci/Tech
Researchers map malaria parasite
30 May 00 | Human genome
Will the developing world benefit?
21 Jun 00 | Sci/Tech
GM mosquitoes to fight malaria
Internet links:

The BBC is not responsible for the content of external internet sites

Links to more Sci/Tech stories are at the foot of the page.

E-mail this story to a friend

Links to more Sci/Tech stories