H5N2 Bird Flu Spreading

OMAHA (DTN) -- It was a busy week for the H5N2 highly pathogenic avian influenza as the flu spread to more turkey farms in northern states as well as Canada.

Dr. John Clifford, USDA's chief veterinarian, said in an interview Friday that USDA continues to examine how commercial turkey flocks are being infected. USDA is looking at the affected operations to see the levels of biosecurity measures in place.

Clifford said the epidemiology would hopefully determine if the cases are simply pinpoint introductions where turkeys came in contact with a wild bird or if there are human causes to the clusters of cases in some parts of Minnesota.

"We need to be able to continue to do our epidemiological work to make sure whether we are getting pinpoint introductions or any kind of lateral spread," Clifford said.

Studies by USDA's Agricultural Research Service have shown turkeys are far more susceptible to the influenza than chickens. Thus, large turkey production areas are becoming hotbeds for the virus.

Most of the birds were indoors, but heating or ventilation and airflow all could have led to the spread of the influenza. Water fowl may not get in, but feces from wild birds could. Producers are taking increased biosecurity measures to avoid limiting exposure.

"One of the things we are emphasizing is the importance to clean the trucks, any kind of vehicle, or person entering that facility," Clifford said. "We need the personnel clean going in and out of there to use proper practices with regards to prevention of the virus."

That includes assuring clean footwear in and out of the poultry house. "Obviously we have not and the industry has not been able to stop this virus from spreading," he said.

Minnesota now has had 13 cases scattered over nine counties in southwest and south-central parts of the state. On April 8, a flock of 300,000 turkeys was found positive. On April 10, four flocks totaling 189,000 were confirmed infected in the state in Cottonwood, Lyon, Stearns and Watonwan counties. In total, more than 800,000 turkeys in Minnesota farms have died or had to be euthanized.

South Dakota also reported two turkey flocks infected this week as well, totaling 87,000 birds.

More than 40 countries have banned poultry imports from states that have been infected by the bird flu. Missouri and Arkansas reported infected commercial turkey operations in March.

Minnesota raises about 45 million turkeys a year. It's a $750 million industry for the state. Only North Carolina matches Minnesota in turkey production and value.

Clifford said the chain of movement of the H5N2 virus is unexpected. The influenza was derived, or "reassortant" from strains of the H5N8 virus that came from Asia into the Pacific Flyway. USDA reported to the World Organization for Animal Health (OIE) that H5N2 was a reassortant -- a term for mixing genes -- and led to the H5N2 that is carried by wild birds but attacking susceptible commercial turkey farms.

Clifford said the movement and mixing of H5N8 in wild birds crossing through various Asia and North America flyways is unique. It has mixed now twice with N1 and N2 strains.

"We've seen this H5N8 move through a large number of international flyways, which, to my knowledge is the first time we've seen that," Clifford said.

Veterinarians and the industry will have to see if H5N2 dies out in the warmer weather or returns next winter. If it does come back, it's likely the strain would be in all four flyways and affecting commercial turkey operations in other major states such as North Carolina. Clifford noted that cases this week included turkey farms hit by H5N2 in Ontario, Canada, suggest the virus is already moving farther east.

"The indication is that it's already in the Eastern Flyway as well," Clifford said.

Information on poultry biosecurity: https://www.bah.state.mn.us/…

Chris Clayton can be reached at Chris.Clayton@dtn.com

Follow him on Twitter @ChrisClaytonDTN

(ES/AG)

Copyright 2015 DTN/The Progressive Farmer. All rights reserved.