A juvenile black bear on exhibit at a northeast Iowa petting zoo died Friday, and a laboratory confirmed on Saturday it had died of rabies. That places at risk some people who came into contact with it.

The bear, named Chief, was at the Swenson Wild Midwest Exotic Petting Zoo on the Rick Swenson farm near Clermont. In the past month, up to 400 people are estimated to have had possible contact with the animal, including about 150 people at an August 14 barnwarming near the town of Holy Cross.

However, merely having touched or even petted the bear would not have placed people at risk. To be exposed to the rabies virus, they must have contact with the bear's saliva, which then must get into the body through a cut, bite, nip or body opening such as the nose, eyes or mouth. That is considered likely to have occurred because Chief was known to playfully nip and lick zoo visitors.

The zoo's guest book showed that visitors had come from as far away as California and Australia, but most were from Iowa and nearby states. People who have had such contact with the bear since July 30 should see their doctors immediately. Some may be required to receive a rabies vaccination, which amounts to five shots of the vaccine and one to two shots of immune globulin in the shoulder over a period of a month. The shots are similar to childhood immunizations or flu shots. Rabies is 100 percent fatal for humans. Vaccine is the only way to prevent the disease.

Rabies has for many years been a public health problem. However, the number of Iowa cases (153) declined last year from the year before (160). Twenty-four persons have died from rabies in the United States since 1981; 21 of those were due to bat-related strains of the virus. None of those deaths were in Iowa, which hasn't had a rabies death since 1951.