Live poultry brought into the area last month was infected with avian flu and officials are trying to round up the birds so they can be destroyed before infecting other birds, Maryland and federal officials said yesterday.

About 370 chickens and other birds owned by Ralph Knox of Taneytown were confiscated by the Washington Humane Society Dec. 8 after District Police arrested Knox's grandson for peddling the live birds from a truck without a permit, according to Jean Goldenberg, executive director of the Humane Society. She said that many of the birds appeared ill. She said that all 198 chickens were destroyed and sent to labs in College Park, Salisbury, Md., and Ames, Iowa, for examination.

Meanwhile the other birds, including pigeons, guineas, doves and game birds known as chuckers, many of which appeared healthy, were given to persons in Maryland who offered to take care of the birds, said Goldenberg.

Later it was discovered that the chickens had been infected with avian flu, a highly contagious and often deadly disease in birds that affects the upper respiratory tract. The disease does not affect humans and cannot be contracted from eating diseased birds, officials said.

Dr. John Shook, a veterinarian for the state agricultural department, said the 300 to 500 birds on Knox's Taneytown farm will be destroyed, along with birds owned by an Upper Marlboro collector who adopted some of the birds from the District Humane Society. State officials are still trying to trace some pigeons placed elsewhere in Maryland by the Humane Society.

"There will be no threat to the Maryland poultry industry if we react quickly," said Shook.

The strain of the disease found in Knox's birds is similar to the one that was responsible for the death or destruction of more than 60,000 chickens in Cecil County early last year, part of an epidemic that swept through the poultry industry in Pennsylvania, Virginia and Maryland.

The last isolated case of the virus in the three states was reported in April 1984 and the area quarantine was lifted in October, according to Nancy Winswald, a veterinarian for the U.S. Department of Agriculture. She said this is the first outbreak in Prince George's County, which has few poultry farms.

"The risk would be worse if the birds went to the Eastern Shore where there are so many farms," Winswald said.

The state and federal departments of agriculture are attempting to find the source of the flu by finding out where Knox bought the birds. Officials are also attempting to track down people who may have bought birds from Knox's grandson before the Humane Society confiscated the birds, but Shook said that task is more difficult because Knox did not keep lists of customers and did business on a cash basis.