Two more monkeys have tested positive for exposure to a dangerous bacterium at the Tulane National Primate Research Center near Covington, officials said Friday, even as state and local authorities complained about Tulane withholding information about 177 potentially exposed monkeys.

The two new monkeys showed an immune response to the bacterium but had no symptoms of infection by Burkholderia pseudomallei, which is native to southeast Asia and Australia and can cause melioidosis, a potentially fatal disease in humans and animals.

Scientists at the primate center have been researching potential vaccines to protect against the bacterium, but that research was being conducted on rodents in a highly secured lab.

In November, however, two monkeys showed signs of the disease and eventually had to be euthanized, leading to an investigation into how the bacterium escaped from the lab. During that investigation, two more monkeys tested positive for exposure, and another one became ill and had to be euthanized.

Friday’s announcement that two more monkeys showed antibodies consistent with exposure to the bacterium brings the total of confirmed exposures to seven. The two latest monkeys will be retested to confirm their positive tests, officials said.

How the bacterium escaped the lab remains unknown, but the investigation has focused on the center’s veterinarian clinic. All of the monkeys that have showed signs of exposure were treated in one room of the clinic, Tulane University spokesman Michael Strecker said.

The most recent pair of monkeys to test positive were in the clinic during October and November, the federal Centers for Disease Control and Prevention said.

The latest news followed a Thursday story in USA Today that said 177 monkeys that were treated in the clinic during the period when the bacterium is thought to have been at loose there were returned to their cages in the center’s 5,000-strong monkey breeding colony, greatly expanding the number of potential exposures.

Tulane officials have said they have tested nearly 400 monkeys, but the latest revelation means the testing will have to be expanded, Strecker said.

The USA Today story also quoted St. Tammany Parish President Pat Brister as saying it was “unacceptable” that she was learning about the 177 monkeys from a reporter and not from Tulane.

“It certainly raises a red flag to me that I’m not hearing everything from them,” Brister told USA Today.

Brister’s comment echoes statements she made nearly a month ago after the initial reports about the first two monkeys’ infection and the possible infection of a U.S. Department of Agriculture investigator who had been sent to the center to investigate the problem.

The first two monkeys showed signs of infection in November, but Brister didn’t learn of it until mid-January, when she was asked about it by a WWL-TV reporter. Several weeks later, Brister held a rare Saturday news conference to announce that an investigator who had been to the center might have been exposed to the bacterium while there. That turned out not to be the case, but when asked, Brister insisted that such a breakdown in communication wouldn’t happen again.

Her spokesman said Friday that her comment quoted in USA Today would stand as evidence for how she felt things were being handled by Tulane.

“We have some concerns,” spokesman Ronnie Simpson said.

Parish officials plan to bring those concerns before the other members of the so-called Unified Command: the stable of federal, state and local entities sharing information about the center. That group includes the CDC, USDA, Environmental Protection Agency, Louisiana Department of Health and Hospitals, Governor’s Office of Homeland Security and Emergency Preparedness, Louisiana Department of Agriculture and parish government.

Tulane also is a member of the Unified Command.

“I know that better communication within the Unified Command will be discussed next week,” when CDC officials are again scheduled to visit the site, Simpson said.

Brister wasn’t the only Unified Command member who learned of the 177 potentially exposed monkeys from the media.

Mike Steele, a spokesman for GOHSEP, said he had been asking Tulane how many monkeys might have been exposed.

“Somebody tried to get that number on the conference call this week, and I have heard it asked before,” he said. “I know that’s a question we have tried to have answered, and they have not answered it that I am aware of.”

Steele said he personally had asked the question and never received an answer.

“To the best of my knowledge, they never supplied anyone at GOHSEP with those totals,” he said of the 177 potentially exposed rhesus macaques.

Parish Councilman Marty Gould, in whose district the primate center lies, said Tulane has been holding back information. “The problem is that we are finding out information that Tulane just hasn’t disclosed,” he said. “It’s very disturbing.”

Gould praised the communication from state and federal agencies, but he said he and his constituents are upset with how Tulane has handled the situation.

Tulane spokesman Strecker said members of the Unified Command were aware as far back as January that animals were being moved from the clinic to the cages, but that was before the clinic was suspected as the source of the infections. He refused to respond directly to the comments of Brister, Steele and Gould.

However, Strecker and primate center Director Andrew Lackner have insisted throughout that there is no threat to public health.

The bacterium can be spread only through direct contact and isn’t an airborne pathogen. A raft of tests on air, soil and water near the center, as well as blood tests on monkeys and high-risk employees at the center, have come back negative for the bacterium. Another report in USA Today, however, questioned whether those tests — especially those on the soil — were adequate.

All of the center’s research into “select agents,” a group of pathogens considered to pose a potentially severe threat to human, animal or plant health, has been suspended at the direction of the CDC.

The center sits on a 500-acre campus just south of the Abita River. Colonies of the bacterium can develop in soil after being introduced there through animal or human waste, officials have said. Once there, it can be spread by water runoff after a rain.

After a human is exposed to Burkholderia pseudomallei, it can take years before symptoms appear. Once diagnosed, however, it is treatable with antibiotics.

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