Air Travel Aids Viruses To Go Here, There And Everywhere

Air travel, increasing urbanization and modern farming practices are all helping to spread deadly virus diseases carried by blood-sucking mosquitoes and ticks, according to scientists from the Centre for Ecology and Hydrology at Oxford, speaking on Thursday, 01 April 2004, at the Society for General Microbiology’s meeting in Bath.

The Oxford scientists describe how West Nile virus probably arrived in New York in 1999, and how it rapidly spread across North America killing people and thousands of horses and birds. Apparently the same virus is common in Africa, Europe and Asia, where it causes occasional outbreaks and very few deaths.

“Understanding the dispersal pattern of West Nile virus, and why it appears so harmful in North America, will help us to predict whether or not other unpleasant and dangerous diseases such as yellow fever, dengue haemorrhagic fever, Japanese encephalitis and tick borne encephalitis will alter their dispersal patterns and epidemic behaviour in the future”, says Professor Ernest Gould.

“We have discovered that some of these exotic viruses are continually being introduced into the United Kingdom, probably from Africa, but as yet they do not appear to be causing obvious disease problems, either in humans or in animals”, says Professor Gould.

Mosquitoes or ticks infected with these types of viruses, called flaviviruses, may cause fatal disease in people, monkeys, birds and other animals when they feed on them. Scientists believe these viruses emerged in Africa less than 10,000 years ago, before being dispersed around the world.

The research at the Centre for Ecology and Hydrology is funded through the Natural Environment Research Council and the work shows how the dispersal of flaviviruses is influenced by the movement of carrier ticks or mosquitoes. Also influential are the variations in climate, and human activities such as goods transportation, urbanization, land reclamation, air and sea journeys by business people and tourists, and modern farming practices.

“Our work will enable scientists to predict the outcome of future epidemic outbreaks equivalent to the sudden appearance of West Nile virus in America”, says Prof Gould. “The worst case scenarios can be rehearsed to enable appropriate response strategies to be put in place”.