Dr Erika Cox, clinical microbiologist at Launceston General Hospital, said: "Laboratory tests suggest a new species of microscopic worm is responsible." She added: "People who eat kangaroos and wallabies are at risk of all kinds of parasites that are not normally studied because they don't occur in livestock."

Following Tesco's withdrawal from the 'exotic' meats business as a result of Viva!'s campaign against the killing of kangaroos, Sainsbury are now the only big supermarket chain still selling the meat. Despite having been supplied with detailed evidence of a brutal wildlife massacre, Sainsbury have said they intend to continue with exotic meats.

Professor John Goldsmid, medical microbiologist at the University of Tasmania, claims that the cases illustrate how little is known about the potential for 'native' animals to infect humans. He also questions the safety of exporting 'native' meats from Australia to countries such as the UK and maintains that further research is needed. He stressed that the trend to undercook kangaroo involved "probable dangers".

"This clearly illustrates how the pursuit of a few quick bucks from selling kangaroo, ostrich, emu and alligator meat is not just morally bankrupt but also a possible threat to human health," says Juliet Gellatley, director of Viva!

"The UK is awash with cheap meat and the last thing that's needed is the killing of wild animals. The slaughter of kangaroos already contravenes Article 10 of the EU regulations (Directive 92/45/EEC). The destruction of 5.2 million adult kangaroos and the brutal despatch of four million 'joeys' every year is also a wildlife catastrophe. Sainsbury should now distance itself from this indefensible trade. If it wants bigger profits it should concentrate on the phenommenal growth of vegetarian foods", concludes Ms Gellatley .