Just to put the potential risk in perspective, here are two excerpts from
New Scientist magazine of an interview with Paul Reiter, chief entomologist
at the US government's dengue research lab in Puerto Rico.

**New Scientist vol 167 issue 2257 - 23 September 2000, page 41

First of all, most people think of malaria as a tropical disease. That's
completely wrong. Until very recently it was widespread in Europe and North
America. In the 1880s, virtually all the US was malarious, and even parts
of Canada. When the organisation I work for, the Centers for Disease
Control and Prevention (CDC), was founded in 1946, its principal mission
was to eradicate malaria from the US. In Europe, the disease was endemic as
far north as Norway, Sweden and Finland. In the 1920s, epidemics killed
hundreds of thousands in the Soviet Union, right up to the Arctic Circle.
One of the last European countries to be freed of the disease was Holland.
That was in 1970.

....

Why did malaria decline in the northern hemisphere?

In some places, it was drainage schemes, insecticides, anti-malarial
medicines, and so on. But the most important factors were complex changes
in the way people lived, which reduced their contact with mosquitoes. You
can see this even today. For example, Texans love air conditioning. They
live for much of the year with all their doors and windows closed.
**



and from New Scientist vol 163 issue 2204 - 18 September 1999, page Page 13

**
In Turkey, malaria was almost eliminated by 1989. But a major irrigation
project in the southeast of the country caused cases to jump nearly tenfold
between 1990 and 1994. A massive effort to control that epidemic is almost
solely responsible for a fall in the total number of cases in Europe since
1996, but the control is tenuous. Turkey's tourist boom means that malaria
could start to pose a risk for western Europe.

The WHO thinks that good medical care, vigilant surveillance and chilly
winters will prevent malaria from re-establishing itself in northern
Europe, despite the existence of mosquito species able to carry it.

But the species that live in southern Europe are better at maintaining the
parasite. There were outbreaks of malaria that were spread by local
mosquitoes in Corsica in 1970, and in Bulgaria in 1995, while in 1997 an
Italian caught the disease from a local mosquito.

"The risk for the reappearance of the disease in some areas of southern
Europe, where more efficient vectors are present, is real," warns the WHO.
**

--
Tim C.