BOZRAH -- State Department of Agriculture officials should know by week's end if birds at one of New England's largest egg farms are infected with avian influenza. 

Eastern Connecticut egg farms continue to maintain strict biosecurity measures while testing for the potentially devastating disease, Bruce Gresczyk, state Department of Agriculture acting Commissioner, said. 

The strain of the so-called "fowl plague" is not harmful to humans, but is easily transmitted among fowl through mucus or manure, he said. It is not passed through eggs. 

State and local agriculture officials began an investigation at the end of February to determine if chickens at a Bozrah-based farm were infected. 

At least two of the facilities managed by Kofkoff Egg Farm are under quarantine, according to officials. The farm is headquartered in Bozrah, but also has sites in Lebanon, Franklin and Killingly. 

"The good news is a lot of birds (tested) are not infected," Gresczyk said after preliminary testing. 

But officials still have nearly 400,000 blood samples and tracheal swabs of the birds to test. 

"This is a massive undertaking," he said. 

Kofkoff officials did not return calls Monday. 

State officials estimate Kofkoff handles as many as 4.7 million birds, a large portion of the state's nearly $100-million-a-year egg industry. 

Gresczyk, who declined to confirm the location of the farm, said "it's clearly one of the biggest farms in New England." 

If a breakout is confirmed, the disease could be eradicated through vaccination or by destroying the birds. 

In 2001, 16,000 chickens raised for human consumption on a Scotland farm were destroyed and burned at local incinerators. 

"To depopulate 4 million birds would decimate the industry," Michael Darre, an animal science professor and poultry specialist at the University of Connecticut, said. "That's pretty much every egg-laying chicken in the state." 

As was the case in 2001, the potential outbreak has led Japan to temporarily ban poultry imports from the United States. 

Darre said egg-laying hens on an egg farm typically are transported at the end of their egg-laying cycles. 

Most do not see human consumption, but rather are processed out-of-state as by-products for animal food or fertilizer, Darre said. 

While the potentially affected birds are quarantined, vehicles and people traveling from other egg farms are disinfected as part of the biosecurity measures. 

"If they figure one has it, all have it for security reasons," Darre said. 

Gresczyk said waterfowl and other wild birds such as turkey have the potential to be carriers. If avian influenza is discovered, the next step is finding the source.