By Allison Floyd
Lax biosecurity helped spread avian influenza through a handful of Midwestern states this spring, but the wind also seems to be a factor in transmitting the disease from one farm to another, the U.S. Department of Agriculture said after a study of more than 80 infected poultry operations.
Migrating wild birds originally brought the virus to commercial poultry flocks, but other factors have spread the disease from farm to farm in 20 states, killing more than 43 million birds that either got sick or had to be culled.
No one cause is statistically significant enough for scientists to label it the main way that the virus is spreading, USDA said in a news release.
“The losses are in the hundreds of millions of dollars,” said Auburn University poultry science professor Joseph Giambrone, who called the losses to the national poultry industry staggering. “We can expect a reduction of at least 10 percent in egg laying production and a similar drop in turkey production nationally.”
The recent outbreak began in Canada and spread south along migratory flyways as wild birds deposited waste. But the virus then spread from farm to farm in other ways, USDA found.
“While wild birds are the original pathway for the virus’ introduction into the United States, it appears the virus was spreading in other ways as well, given the number and proximity of farms affected by HPAI (highly pathogenic avian influenza),” USDA said. “For instance, the report provides evidence that a certain cluster of farms was affected by identical viruses, pointing to possible transmission among those farms.”
Genetic tests also show that the virus was getting a foothold in commercial flocks in different areas at different times. In other words, it hasn’t spread from one flock to another to another.
In the USDA Animal and Plant Health Inspection Service report released Monday, the agency confirmed several observations of biosecurity lapses at infected farms:
- sharing of equipment between an infected and noninfected farm;
- employees moving between infected and noninfected farms;
- lack of cleaning and disinfection of vehicles moving between farms;
- reports of rodents or small wild birds inside the poultry houses.
- But, the virus may also spread in the wind.
“APHIS found that air samples collected outside of infected poultry houses contain virus particles, indicating that the virus could be transmitted by air. In addition, preliminary analysis of wind data shows a relationship between sustained high winds and an increase in the number of infected farms approximately five days later,” the agency found.
While poultry producers in the Southeast have been spared from the virus, scientists and industry leaders are warning producers to be vigilant and expect the virus will begin to spread again when wild birds begin to fly south in fall.
“All our Alabama poultry growers have biosecurity measures in place,” said Alabama Extension poultry scientist Ken Macklin. “Biosecurity measures are the first line of defense against avian influenza and other poultry diseases.”
“These cases in commercial poultry operations in the upper Midwest have mostly been linked to a failure of biosecurity,” said Macklin. “Growers may have thought they were following biosecurity guidelines fully, but it seems that there were lapses.”
Macklin said the potential production loss is why Alabama producers are working hard to keep their flocks free of the disease. According to Auburn University research done in 2012, poultry and egg production and processing contributed more than $15 billion to the state’s economy and employed more than 86,000 people.
“The virus can survive for days especially if it is in water,” said fellow Auburn poultry scientist Ken Macklin. “In water, the virus can survive up to 100 days with a water temperature of 63oF. But when water temperatures reach the 80s, the virus can survive for less than a month.”