An animal clinic worker at the Tulane National Primate Research Center in Covington has tested positive for exposure to a potentially deadly bacterium that escaped from a high-security lab at the center and infected several monkeys, officials said Wednesday evening.

The results of blood tests on the worker showed antibodies consistent with exposure to Burkholderia pseudomallei, which is native to southeast Asia and Australia and can cause melioidosis, a potentially fatal disease.

The worker’s blood had barely enough antibodies to trigger a positive result, and further tests are needed to confirm the initial positive reading, according to a statement from the federal Centers for Disease Control and Prevention. Confirmation could be received as early as next week.

The employee has no symptoms, the statement said.

In addition, blood tests on 67 rhesus macaque monkeys at the center showed another that had antibodies consistent with exposure to the bacterium, bringing the total of confirmed exposures to eight. Like the previous seven — three of which became infected and were euthanized and four of which showed signs of exposure but have not become sick — the eighth monkey had been treated in a room at the primate center’s clinic.

That treatment room is the focus of a probe led by federal investigators from the CDC and the U.S. Department of Agriculture. Investigators are seeking to learn how the bacterium — which is on a list of pathogens deemed to pose a potentially severe threat to human, animal or plant health — got out of the lab. While the investigation is ongoing, Tulane has been ordered to shut down its work with all such pathogens, known as “select agents.”

Investigators began looking into the problem after two monkeys were diagnosed in November with infection from the bacterium. Both were eventually euthanized. The monkeys were not part of any experiment. In 2014, experiments involving Burkholderia pseudomallei at the center were being conducted only on rodents, officials have said.

Rather, the infected monkeys were part of the center’s nearly 4,000-strong monkey breeding colony, a collection of mostly rhesus macaques that are kept outside in large cages.

In early February, officials said an investigator who had been at the center reported symptoms of melioidosis and checked herself into a hospital. Blood tests confirmed antibodies consistent with exposure to the bacterium, but later tests suggested that her exposure had occurred during earlier travel to areas of the world where the bacterium is endemic.

The bacterium can be carried for years before any symptoms manifest themselves. The symptoms often mimic those of other diseases, which sometimes makes proper diagnosis difficult. But if properly diagnosed, the disease is treatable with antibiotics.

Fear that someone may try to weaponize the bacterium is why it appears on the list of select agents.

A raft of tests on soil, air and water near the center have been negative so far, and even though some have criticized the scope of the testing, the CDC has said it’s unlikely there is any threat to the general population.

Follow Faimon A. Roberts III on Twitter, @faimon.