Disease Trackers Miss Flu Cases By Testing Birds at `Wrong End'

By John Lauerman

Dec. 12 (Bloomberg) -- Disease trackers in countries including the U.S. are missing bird flu cases when they test only fecal samples without checking the mouth for the virus, a top researcher said today.

Birds that show no avian influenza in standard fecal and rectal exams may be able to spread the virus on their breath, said Robert Webster, a bird flu expert at St. Jude Children's Research Hospital in Memphis, Tennessee. Experiments by Erasmus University virologist Albert Osterhaus and Webster show that H5N1-infected birds may have as much as 10 times more virus in their upper airways than in their excrement.

``In many cases, we're testing the wrong end of the duck,'' Webster said in an interview in Singapore.

Osterhaus and Webster are among more than 100 researchers who are attending a Singapore infectious disease conference to look for better ways to control the lethal H5N1 bird virus that scientists say may spark a pandemic in people. International animal health officials are trying to change testing standards so infected birds don't escape notice, Webster said.

The H5N1 avian flu has killed at least 154 people since late 2003, according to the World Health Organization.

The Food and Agriculture Organization of the United Nations and a WHO research advisory group both have recommended that scientists swab animals' upper airways for bird flu virus.

The FAO recommends both tracheal and rectal testing of infected birds on its Web site. The agency will change the Web site to emphasize airway testing for H5N1, said Peter Roeder, an animal health officer who helped Indonesia set up its bird surveillance.

Bigger Splash

``This virus behaves very differently from other avian influenza viruses and its presence in the trachea is one of the characteristics we've had to take into account,'' Roeder said today in a telephone interview. ``Perhaps we should make a bigger splash about it.''

Following infected birds is an essential part of the fight to prevent or at least blunt the impact of a potential outbreak, researchers said at the five-day conference, which runs through Dec. 14. Potentially dangerous new mutations that might give H5N1 the ability to spread among people are cropping up in birds, and perhaps other species including cats and dogs, said Ron Fouchier, also an Erasmus virologist, at the conference.

``We've been hearing about hundreds of reports of dead cats from Indonesia,'' Fouchier said today in an interview. ``We've also had several reports of infected dogs from countries of the former Soviet Republic.''

Influenza infects birds worldwide. By studying bird-infected excrement in animal markets and in the wild, Webster showed decades ago how flu germs evolve into new forms that gain the ability to cause disease in humans.

Research by Webster and Osterhaus has shown that sampling excrement and the end of the birds' digestive tract, called the cloaca, is no longer sufficient because of H5N1 is focused in the birds' airway. Osterhaus, who is developing a comprehensive European bird monitoring program called Newflubird said that protocols are challenging some countries ethical standards for animal treatment.

``In the Netherlands, this testing is considered an animal experiment,'' he said.

To contact the reporter on this story: John Lauerman in Boston at jlauerman@bloomberg.net .

Last Updated: December 12, 2006 08:03 EST

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