Malaria: Searching for treatment
DUBLIN — Here in Ireland, a country not much troubled by mosquitoes in summer, some of the most exciting research in the struggle against mosquito-borne malaria is taking place. It has to do with the discovery of Mal in the laboratories of professor Luke O’Neill at Trinity College Dublin.
Mal is not a person — rather, it’s a protein that helps determine whether a person succumbs to malaria after a mosquito bite. Researchers working at Trinity — who are collaborating with a team under another Trinity scholar based at Oxford University, professor Adrian Hill — believe they are close to finding an effective vaccine against the mosquito-borne disease.
I meet the tousled-haired, fast-talking O’Neill at Trinity’s Science Gallery beneath a large sign saying, “Infectious,” the title of an exhibition he’s organized to show how infections spread in the human body. He takes me to a large wall exhibit, like a giant newspaper page full of print with no gaps between the letters, that is the chemical formula for Mal.
He explains that when the human body senses the presence of the mosquito-injected parasite that causes malaria, a set of sensors locks onto the intruder and sends a message to Mal, which wakes up the immune system to fight it. It doesn’t always succeed, said O’Neill, who directs Trinity’s School of Biochemistry and Immunology.
“The mystery has always been, why do some people get malaria and others not — well in part it’s Mal,” O’Neill said.
Hill, the director of the Jenner Institute and professor of human genetics at the University of Oxford, has shown that there are two variants of Mal in humans — the good and the bad — and these variants determine how the immune system responds.
The good type of Mal organizes a successful counterattack against malaria, whereas the bad Mal is either underactive, or it is overactive and destructive, like friendly fire. O’Neill calls the good type the “Goldilocks effect”: not too hot, not too cold, just right. The finding of these pathways in the body is, he believes, the key to a successful fight against malaria.
The team working under Hill is making progress in trying to activate Mal in specific ways to develop the vaccine. “Trials among chimpanzees have had a 80 to 90 percent success rate,” O’Neill said, “so that gives us hope with humans.”
He believes that a vaccine is much closer now than a year ago, and that it is the only way to deal effectively with malaria, which infects 250 million people a year and kills almost a million, according to World Health Organization figures. The mosquitoes that transmit the disease are becoming resistant to insecticides, and the parasites are becoming increasingly resistant to the drugs used for treatment.
“These numbers seem alien to us but these are real people, with children and families who are dying of this infectious disease, and if we put more effort into it we could find a cure,” O’Neill said, with some passion. “I hate to quote Bono,” he added, “but it’s a question of justice.”
There is currently no licensed vaccine against malaria on the market, though research is proceeding on vaccines of the type that eliminated such diseases as polio, and work by injecting weakened bacteria to create antibodies.
Advances have been made in the United States under the Malaria Vaccine Initiative, funded by the Bill and Melinda Gates Foundation. Malaria affects mostly poor African and Asian countries, but there is no reason for complacency, even in Ireland. Malaria was once the scourge of this country. Oliver Cromwell died in 1658 from malaria contracted in Ireland during his military campaign.
With climate change, mosquitoes have reappeared in southern parts of the Emerald Isle in recent years. While not malaria-bearing, their bites can be very painful and O’Neill offers advice on what parts of the body to cover up. “Two years ago a group found a chemical in our sweat that attracts mosquitoes,” he said. “It gathers in your wrists and in your ankles. It mimics a sex hormone, so mosquitos come and think they are going to have a good time!”
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