Maryland health officials are expanding their search for people who had contact with a rabid 6-week-old Jersey calf at a Prince George's County educational center.

Authorities say that in addition to about 70 children who recently visited the Hard Bargain Farm Environmental Center in Accokeek, they believe that other visitors include residents of Prince George's, Charles and Montgomery counties and Washington.

"Local health departments are reaching out to all known contacts who've visited the farm during this time period and we need the public's help to make sure no potential contact is missed," Dr. Katherine Feldman, chief veterinarian for the Maryland Department of Health and Mental Hygiene, said in a statement.

"It's critical that we identify everyone who has been close enough to this calf to come in contact with its saliva," Feldman added.

Officials have said they are not sure whether any of the children who recently visited had touched the tan Jersey calf, which has a white spot on its face and another on its hindquarters. Officials also want to know if any of the children, or anyone else, bottle-fed the calf, which has been euthanized.

Rabies is a deadly disease transmitted by saliva from infected animals. Treatment includes a series of shots over a two-week period.

While rabies is mostly found in the wild, in such animals as raccoons, foxes and bats, it can show up in domesticated animals, the state Health Department cautioned in the statement. Officials said that in Maryland, nearly 400 animals were diagnosed with rabies last year.

People who have visited the farm since Dec. 21 are urged to call their local health department:

* Washington residents should dial 311.

* Montgomery County residents should call 240-777-1755 and leave a contact number on the recording.

* Prince George's County residents should call 301-583-3750.

* Charles County residents should call 240-216-4055 or 240-299-4693.