'Magic possum bullet’ near

Scientists are close to developing a "magic bullet" toxin which can kill possums but is harmless to native animals and birds.

AgResearch has identified differences in the cell structures of marsupials compared with placental animals and hopes to use that knowledge to target possums.

Scientist Bernie McLeod said the company was working with the University of Otago on a toxin that diverted water and nutrients from the pest's internal organs to the gut.

"You would get a sudden drop in blood pressure and that stuffs up virtually every organ in the body," he said.

"An equivalent in humans is cholera toxin which does just that and that would kill a small child very quickly.

He said they had estimated a toxin which worked in this way could kill a possum in an hour.

"Such a toxin would have no effect on farm animals, companion animals or birds because they operate secretion using different mechanisms."

He said the toxin could affect wallabies and kangaroos but no other animals.

Possums were declared a pest in 1947 and are a major threat to New Zealand native forests. They eat plants, birds and their eggs and are known to carry disease.

- NZPA