Eureka moment discovers Trojan duck

Ducks harbour and replicate the virus in the wild, transmitting it to other poultry whenever they defecate in open water. Photo / Mark Mitchell

Robert Webster grew up on a farm in Balclutha.

As a boy, he raised khaki campbell ducks. Ever since, he has devoted his career to cracking the mysteries of bird flu.

Webster graduated from Otago University and worked for the Department of Agriculture before taking a PhD from the Australian National University in Canberra.

Now 79, he is based at the Department of Infectious Diseases at St Jude Children's Research Hospital in Memphis, where he presides over the world's only laboratory studying the human-animal interface in flu.

"The world owes a huge debt to Bob," says Ilaria Capua, director of the World Animal Health Organisation's national reference laboratory for avian influenza in Padua, Italy.

"In many ways, he is both the father and mother of influenza."

Webster's Eureka moment came in his own backyard. "We had travelled the world and got nothing. Then someone mentioned it was duck-hunting season in Memphis."

Webster and a colleague went to a bait shop by the Mississippi river and sat beside two women whose job it was to pluck the birds.

By the end of the hunting season, they had found the missing link: 5 per cent of the ducks were carrying the flu virus.

Webster had found his "Trojan duck". Ducks, he explains, harbour and replicate the virus in the wild, transmitting it to other poultry whenever they defecate in open water. But while H5N1 and other wild viruses, such as H9N2 and H7N7, are deadly to farmed poultry, most ducks do not get sick at all.