Delaware officials said in a statement that testing continued yesterday inside and outside a six-mile radius around two farms that were found to be infected.
Also, cautionary measures such as quarantining, cleaning and destroying of birds will continue for the next two weeks.
No new cases were reported to federal or state agencies yesterday, a government holiday. A farm in Lancaster County, Pa., tested positive over the weekend and was quarantined.
The strains of bird flu discovered on commercial farms in Delaware and Pennsylvania and in live bird markets in New Jersey are different, but none are considered harmful to humans who come in contact with the birds or eat the meat or eggs, health officials said.
The U.S. Department of Agriculture plans to continue to press the 11 nations that have banned U.S. poultry products to reopen their markets.
The USDA is "working to assure our trading partners of the safety of U.S. poultry," Bobby Acord, administrator of the department's Animal and Plant Inspection Service, said in a statement over the weekend.
"The [avian influenza] strain in affected states is not the same strain of the virus that is affecting birds and some people in Asia.
"The Asia strain is highly pathogenic avian influenza, and the United States has not had an incidence of HPAI for 20 years," Acord said.