Climate change could bring new diseases to the UK, as organisms which can only survive in warm countries, begin to flourish here, a scientist will warn tomorrow. Paul Hunter, Professor of health protection at the University of East Anglia, will tell delegates at the British Association for the Advancement of Science's Festival of Science in Norwich, that there are already clear signals that infectious diseases are changing as a result of climate change.

He will give a number of examples of cases which have already be seen in Europe, including the appearance in the last three weeks of "bluetongue disease" on cattle farms in the Netherlands, Germany and Belgium.

The disease, which causes bleeding and a blue tongue and can be fatal to animals, is carried by tiny biting midges called Culicoides, commonly found in sub-Saharan Africa and South America. It may have found its way to the Netherlands via an imported zoo animal or on an aeroplane, but once here, Professor Hunter says, its survival will be helped by the particularly hot European summer.

A second example is a condition caused by a marine virus called vibrio vulnificus, which turns muscles black and kills half of people who contract it. It was previously only reported in the Gulf states of the USA, but this year three cases have been seen around the Baltic, including one death.

Although there is no evidence that it is in UK waters yet, nobody has been looking for it according to Professor Hunter. He says: "Although the direct threat from climate-related infectious diseases in the UK is likely to be limited to food and waterborne disease, mass migration of peoples displaced from developing nations that are more severely affected, is likely to have a far greater impact, causing a rise in cases of diseases like tuberculosis and HIV."

Today the festival will hear from the association's new president, Frances Cairncross, is to warn world leaders need to think about adapting to climate change rather than focusing only on trying to fight it. Ms Cairncross says: "There are two main ways we can respond to climate change: we can adapt, or we can try to slow the process. In practice, we will do both. But adaptation to climate change has had relatively little discussion."