Panic was the reaction of New Yorkers last Thursday when the mayor, Mr Rudy Giuliani, announced that the city would have to be sprayed with pesticide in an effort to eradicate mosquitoes carrying the potentially lethal St Louis virus strain of encephalitis.
By the weekend, three people had died and nine other cases had been confirmed, with a further 60 in the "suspected" category.
Not surprisingly, this major public health threat, and the extreme measures needed to combat it, has scared New Yorkers. Banner headlines in the tabloid papers and round-the-clock reports on local television stations provoked panic-buying of mosquito sprays. But hardly any of these reports drew the obvious conclusion, that this outbreak indicates that we are in the grip of global warming.
The truth is that cities in the northern hemisphere, like New York, are becoming more vulnerable to potentially lethal strains of tropical diseases such as the St Louis strain of encephalitis - first identified in the 1930s' "dust bowl" era - which is fatal in one in 10 cases.
St Louis encephalitis is a virus from the yellow fever family, which causes headaches and, in the worst cases, viral meningitis and encephalitis (inflammation of the brain).
An outbreak near Disneyworld, Florida, two years ago led to holidays there being cancelled.
In his 1996 book, Global Warming: Can Civilisation Survive?, Paul Brown noted that many of the main infectious diseases are caused by parasites or viruses transmitted to humans via insects such as mosquitoes and ticks, known to the medical profession as "vectors".
Extra heat and humidity mean that tropical diseases, such as malaria, "can move north and south to trouble previously immune populations in temperate regions", he wrote.
So one of the first signs of general global warming would be the spread of malaria belts from tropical areas.
"At the moment, the types of mosquito that carry malaria only thrive in hot countries, but with an increased global temperature of a couple of degrees, an irritating insect could potentially become a carrier of a killer disease almost worldwide," Mr Brown warned three years ago.
He also noted that mosquitoes are responsible for the transmission of dengue fever, a severe influenza-like disease which, if left untreated, can kill 15 per cent of those infected.
As with other mosquitoes, those responsible for carrying it are more active in warmer climates.
In 1998, the UN Intergovernmental Panel on Climate Change, made up of more than 2,000 scientists, predicted that warmer conditions for mosquitoes and other "vector organisms" would increase the potential for outbreaks of tropical diseases in the US and Europe.
Malaria is a major killer. The World Health Organisation estimates that up to 500 million people are infected, of which some two million die each year, mainly in Africa.
But this pattern is set to change dramatically because of global warming, according to Mr Brown.
New York and other US east coast cities, such as Washington DC, have been experiencing unstable weather lately, with droughts followed by thunderstorms providing the ideal breeding conditions for various types of mosquitoes, including those carrying tropical diseases.
Florida is spending $100 million a year to eradicate malaria. "It is only a matter of time before the climate envelope in which it and other tropical diseases survive moves northwards both in Europe and the US," according to Dr David Viner, of the University of East Anglia.
Dr Graham Fry, lecturer in tropical medicine at Trinity College Dublin, said there had been a malaria outbreak in Luxembourg which was attributed to mosquitoes brought back by tourists returning from tropical countries, a phenomenon known as "airport malaria".
"In any hot, humid situation, there will be mosquitoes," he said.
"We have always had mosquitoes in Ireland, but they are not the ones carrying tropical diseases. However, with a lot of people moving around more easily with international travel, there is always a risk".
Dr Fry said it would take some time for an epidemiological study to determine whether the outbreak of St Louis encephalitis in New York was locally bred or not. If it turned out to be indigenous, this could be taken as an indication of one of the effects of climate change.
Coming in the wake of a summer heatwave that sent temperatures in Chicago into the low 40s Celsius and killed well over 100 people, the spraying of New York with pesticide might bring it home to Americans that they really must start taking action to combat global warming.