The latest daily update from the United States records that there have been 97 outbreaks of H5N2 highly pathogenic avian influenza up to 28 April. The majority of outbreaks have been in commercial turkeys (74); 10 have been in commercial chickens, one in a mixed commercial flock and 12 in backyard flocks.

Making up the total toll of more than 15.4 million birds are almost 10.57 million commercial turkeys, 4.75 million commercial chickens and 70,000 backyard poultry.

Frustratingly for all concerned, there is yet no sign of a slow-down in the spread of the virus. Having wreaked havoc in Minnesota's turkey flocks, it now seems to have widened its reach to target Iowa's commercial chicken sector. Both these areas are near to the Mississippi flyway for migrating birds but those under the Central flyway have also been affected, including one large mixed poultry flock in North Dakota in the last week.

The reasons for the spread of the infection across the US is are hotly debated. Some experts doubt that every outbreak can be blamed on migrating birds or biosecurity breaks but they have proposed that the virus may be carried on the wind.

The virus has been detected for the first time in two wild birds in Kentucky in the last week.

The state of Minnesota has called a state of emergency: the National Guard is helping with the clean-up operations and the first financial compensation has been approved for affected farmers. That must offer only the smallest relief to those who have lost their entire flock through death or humane euthanasia.

At an international conference on avian influenza at the University of Georgia recently, the important role of hobby and smallholder flock owners in the control of the disease was not overlooked.

A third outbreak of H5N2 avian flu has been confirmed in Canada; all the affected farms are in Ontario.

In other news of avian flu, it has been reported that Egypt continues to battle the disease in both people and poultry.

The H5N1 high-path virus has been detected in wild birds near the Caspian Sea in Russia for the first time.

In the last week, it has been reported that a village poultry flock in the north of Viet Nam has been wiped out by the H5N6 high-path virus.

Taiwan has reported five new outbreaks of avian flu – four at poultry farms and one at a processing plant.

On a more positive note, Japan has been declared free of avian influenza and the Netherlands has lifted poultry movement restrictions following a single outbreak of low-pathogenic avian flu in poultry last month.

Also offering hope for the future, a team of Chinese scientists has had some success using a novel oral vaccine to protect poultry against the highly pathogenic H5N1 virus.