Imported animals disease threat

The poison arrow frog carries an infection that kills European frog species

More needs to be done to prevent imported animals spreading diseases to humans and wildlife in Britain, says the Zoological Society of London (ZSL).

Its report says a national monitoring agency should be set up to detect diseases more quickly and to help prevent them from spreading.

Around 75% of emerging diseases in humans come from animals, including Aids, Bird Flu and West Nile Virus.

Yet animals continue to be moved across borders with little scrutiny, ZSL says.

Ways that animals are moved around include the pet trade, hunting and tourism.

"A lot of wildlife diseases can be transmitted to livestock and even to humans," Dr Andrew Cunningham, of the Zoological Society of London, told BBC News.

Scientists are increasingly concerned about the threat from bird flu

"It is essential that the UK has increased protection from the danger of emerging infectious diseases as they can devastate our already threatened native wildlife and pose a real hazard to human health."

Native British species have already suffered due to diseases spread by imported animals.

Examples include the decline of red squirrels due to the parapox virus, the death of hundreds of thousands of native frogs due to ranavirus, and the near extinction of crayfish due to fungal disease.