Zoo Worker’s TB Infection Tied to Lax Policing of Rules

Lax enforcement of longstanding policies to protect workers apparently led last year to at least one employee of the San Diego Zoo being infected with tuberculosis by a Tibetan macaque.

Although zoo officials say the problems have been corrected, a federal inspection in February found that workers who had contact with animals continued to do so without gloves, boots and other protective gear.

And, on Friday, at least two key officials were not aware that zoo policy requires workers who come into contact with animals to be tested every six months to see if they have acquired TB or other diseases from their charges.

Last summer, after three of the macaque monkeys died or were put to death because of TB, four employees at the zoo hospital were found to test positive for the disease. Three had not been tested for years, so it was not known whether they were infected at work.

Tested Negative at First

However, the fourth, a keeper at the hospital, apparently acquired her case from a macaque, because she tested negative for TB shortly after the animals arrived in the hospital in March, 1987, said Don Jannsen, director of veterinary medicine.

The zoo had rules that might have kept the worker from being exposed, and might have made it easier to tell if all four TB infections were caused by the macaques, but they were not enforced, zoo officials admitted.

“The policy has been on the books. But the problem we have had is the enforcement of the policy,” said Dave Mathaias, manager of safety and health the past year. “The adherence to the policy has been left too much to a discretionary decision.”

Jannsen, who moved to his post from the Wild Animal Park a few days after the macaques arrived at the zoo, said workers at the hospital seemed to view wearing masks, gloves and protective clothing as voluntary even though they were working with quarantined animals. In May, he issued a set of written rules requiring such clothing and other protective measures.

But, because keepers can develop a personal relationship with the animals, especially primates, such procedures are hard to enforce, he said.

“Those are still animals that can infect us with diseases, but they’re the ones you want to touch and want to let them touch you,” Jannsen said.

“It’s more difficult than it is in a laboratory facility, where the animals are very much less personal,” Jannsen said. “And for that reason probably the standards for primate care in zoos is not to wear a mask and gloves every time you handle a primate.”

OSHA Found Violations

In February, OSHA inspected the zoo and found that keepers were not wearing protective clothing when handling animals and cleaning their enclosures. The agency said the violations of worker safety regulations were “causing or likely to cause death or serious physical harm” and fined the zoo $1,060. The zoo is contesting the citations.

Although regular TB testing of employees is not an issue in the OSHA case, it has made the macaque incident more difficult to sort out.

Mathaias said the zoo has begun enforcing a policy requiring TB tests every six months for employees who work with animals. But the message apparently remains unclear.

Martha Baker, manager of public relations for the Wild Animal Park, said Friday afternoon that she and the park’s head veterinarian understood that TB tests are voluntary there.

Bacterial Disease

Tuberculosis is a bacterial disease of the respiratory system. When a victim coughs, the germs are expelled into the air where they can be inhaled by someone else. However, close contact, usually indoors, is necessary, said Dr. Dixie Snider, director of the division of tuberculosis control for the U.S. Centers for Disease Control. A person can be infected but not be contagious for an indefinite period of time.

“Instances in which there is transmission from animals to man are considered rare,” Snider said. “One of the things that I think is standard practice is that those who work with primates are skin-tested on a regular basis.”

At the San Diego Zoo, the macaques arrived from China last March and were put into a required 33-day quarantine at the hospital, Jannsen said. An initial TB test on one animal was positive, but further tests showed no problem.

At about the same time, Jannsen suggested to his new employees that they should be tested for TB if they hadn’t been. Some--including the keeper who later tested positive--followed his advice.

Thirty days later, a second set of tests showed two macaques with signs of TB that were not confirmed by further tests. But the two animals were kept in quarantine just to be sure. “In July or August we were going to repeat the diagnostic tests, and at that time the first animal had an advanced case of TB, an active case. The animal died during the exam,” Jannsen said.

After an exam showed an active case in the second animal, it was put to sleep. The same was done to a third when X-rays showed it had lesions in its lungs.

The three other macaques remain in quarantine in a research area at UC San Diego, Jannsen said, and have been treated with preventive antibiotics. They may be returned to the zoo quarantine in the next couple of months and eventually put on display, he said.

It was after the first animal died that a broad range of employees at the hospital were tested, and four found to have positive TB tests. None has an active case of TB, so they are not contagious.

Picked Up Records

One, secretary Kay Munduate, said the closest she ever came to one of the animals was in picking up records from the treatment room where the animals were examined. She isn’t so sure she got TB from a macaque. “You could get this anywhere,” she said.

Snider said there have been a few cases of TB being transmitted without close contact, for instance through a ventilation system aboard a Navy ship. Sometimes TB also can result in drainage from the neck that, theoretically, can transmit the disease. However, the macaques did not have outward signs of disease, Jannsen said.