Bird Flu Rears It's Ugly Head again! By John Gever, Senior Editor, MedPage Today

A new vaccine-resistant strain of avian H5N1 influenza has begun circulating in poultry flocks in Vietnam and China, posing "unpredictable risks to human health," the Food and Agriculture Organization (FAO) warned on Monday.

"In Vietnam, which suspended its springtime poultry vaccination campaign this year, most of the northern and central parts of the country -- where H5N1 is endemic -- have been invaded by the new virus strain, known as H5N1-2.3.2.1," the FAO said in a statement.

No cases of human infection with the novel strain have yet reported by the FAO or its sister group, the World Health Organization. Vietnam has remained free of human infections with any avian H5N1 strains this year, according to WHO.

The FAO indicated that Vietnam's veterinary services had been alerted to the threat and the county is "reportedly considering a novel, targeted vaccination campaign this fall."

The new strain is "apparently able to sidestep the defenses provided by existing [poultry] vaccines," the agency said.

The ongoing H5N1 flu virus epidemic, which was first detected in 2003 when humans began falling ill and dying, has affected wild birds as well as domestic poultry. That has aided the disease's spread out of eastern Asia, and its reintroduction in areas where it was thought to have been eradicated.

The epidemic in bird flocks peaked in 2006 and hit a low in 2008 after aggressive poultry slaughters in affected countries.

But the FAO indicated that poultry infections have been rising again. It said nearly 800 outbreaks had been identified since January 2010, compared with about 300 in 2008.

Recent poultry infections have been spotted in Israel, the Palestinian territories, Romania, and Bulgaria.

The FAO's chief veterinary officer, Juan Lubroth, said the H5N1 virus was most entrenched in Egypt, Indonesia, China, Bangladesh, India, and Vietnam.

Most recent human H5N1 infections have been in Egypt, with another small outbreak under way in Cambodia, according to WHO.

A total of 49 human infections and 25 deaths have been confirmed in 2011, with roughly half in Egypt.

Since 2003, the WHO's human case count worldwide now stands at 565, with 331 deaths.