HARTFORD, Connecticut (AP) -- Connecticut officials said Thursday they have quarantined 4.7 million chickens as they investigate a possible outbreak of avian influenza at an egg farm, a move that prompted Japan to temporarily ban U.S. poultry imports. 

Acting Agriculture Commissioner Bruce Gresczyk said samples from the farm have been sent to a laboratory in Iowa and results are expected next week. 

"This is a devastating disease to poultry but zero risk to humans or any mammal," he said. He also said the disease does not affect eggs and there are no problems with any products the farm has on the market. 

Gresczyk said the particular strain suspected is considered a low-grade pathogen and in some cases is not fatal to chickens. 

But if influenza is confirmed, the state may have to destroy the flock, Gresczyk said. State officials began investigating last week. 

Gresczyk would not disclose the name of the farm, but the apparent outbreak  occurred at Kofkoff Egg Farm, said Michael Darre, a state poultry specialist and  animal science professor at the University of Connecticut. The farm controls more than 90 percent of the state's egg market and produces 12 million eggs every week. 

No one at the farm returned messages Thursday. 

The egg industry is among the top agriculture businesses in Connecticut, with annual receipts of between $60 million and $100 million. 

A strain of avian influenza was disc overed in eastern Pennsylvania. 

That strain resulted in the destruction of 17 million birds in addition to hundreds of thousands that died from the disease, according to Pennsylvania veterinarian and poultry consultant Dr. Dave Kradle. 

That strain also was considered a low-risk pathogen but quickly mutated to something more serious. It resulted in a statewide surveillance program in Pennsylvania that remains in place today, Kradle said. 

As a result of the Pennsylvania outbreak, Connecticut tightened its security in the industry, Darre said. But wild birds such as ducks and geese can be carriers and Connecticut is on a major migratory flight path.