A MYSTERY case of malaria near London鈥檚 Heathrow Airport is being investigated by officials, who suspect the patient may have been bitten by a 鈥渟towaway鈥� mosquito. The person, who works near Heathrow and has been successfully treated, has not recently been to any country with malaria.
Officials from the government鈥檚 Public Health Laboratory Service are trying to establish how it happened. 鈥淚t鈥檚 either from a mosquito or from blood [from a hospital],鈥� says David Warhurst of the PHLS鈥檚 malaria lab at the London School of Hygiene and Tropical Medicine. 鈥淚f we get any odd cases we can鈥檛 explain, we do an investigation to see if it鈥檚 imported or someone who鈥檚 arrived with malaria on a plane.鈥�
Warhurst says that the last British cases traced to a stowaway mosquito were in July 1983, in a village 12 kilometres from London鈥檚 Gatwick Airport. A pub landlord collapsed with hallucinations, and a motorcyclist who had passed through the village also contracted the disease. 鈥淚t seems likely it was the same mosquito,鈥� says Warhurst.
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There have also been 鈥渃lusters鈥� of cases around Amsterdam鈥檚 Schiphol Airport and Charles De Gaulle Airport near Paris. But cases traced to stowaway mosquitoes are rare, as the cabins of all aircraft leaving malaria-infected regions have to be sprayed with insecticide.
In a 1991 report for the PHLS, Warhurst warned that global warming could make it easier for the mosquitoes to survive the English climate, although they shouldn鈥檛 live for more than a day or two. 鈥淚t鈥檚 on the cards,鈥� he says. 鈥淚f we get warmer summers, this can happen more easily.鈥� Warhurst warns family doctors near major airports to be on alert for cases.