Alison Young

USA TODAY

More than 175 monkeys that were potentially exposed to a bioterror bacteria inside a major Louisiana research complex were returned to their outdoor cages before officials knew the deadly pathogen was on the loose from a lab accident.

The new admission by the Tulane National Primate Research Center, in response to repeated questions from USA TODAY, raises further questions about contamination of the environment outside of the massive research campus north of New Orleans. The bacteria, which is not found in the United States and can cause severe disease in people and animals, can live and grow in soil and water.

"Some animals were released from the vet clinic early on, but the key thing is that all the animals have been traced," said Tulane spokesman Michael Strecker. Testing of the animals is ongoing to determine if they have been exposed to the bacterium, Burkholderia pseudomallei.

The primate center is next to wetlands, near a river and neighborhoods and across the street from a school.

If infected, animals that become ill can shed the bacteria in their urine and feces and the organism can colonize soil and water, said Jay Gee, a research biologist and expert on the pathogen at the Centers for Disease Control and Prevention. The colonies can spread to other areas if carried by water runoff when it rains.

Soil scientists from the U.S. Department of Agriculture are currently studying the bacteria's ability to survive in North America, Gee said Thursday. USDA officials could not be reached.

The USDA has previously said it is still studying whether the situation at Tulane's primate center in Covington, La., poses a risk to agriculture. The CDC has said there is no evidence at this time of a public health threat.

The veterinary clinic on the primate center's 500-acre campus north of New Orleans is the current focus of federal and state investigations as the likely place where five monkeys were infected or exposed to the bacteria around November or December. None of the monkeys were involved in experiments with the bacteria – and the pathogen should never have been in the clinic or anyplace else outside the high-security lab where Tulane was doing vaccine-development research.

Officials do not know when or how the bacteria got out of its lab, despite weeks of investigation by the CDC and numerous state and federal environmental, agriculture and emergency management agencies.

In response to repeated questions from USA TODAY since Tuesday about how many animals had passed through the veterinary hospital during the period of suspected contamination, Strecker replied on Wednesday: "No animals are being released from the hospital until the results of testing are known."

After further questioning, Strecker on Thursday afternoon said that 177 rhesus macaque monkeys had been treated and released from the hospital during the period of concern, which spans from November to February. He emphasized that all of the animals are being tested to determine if they have been exposed to the bacteria. It was unclear Thursday evening how many of these 177 monkeys have test results back yet.

So far, Tulane has sent samples to the CDC from more than 340 monkeys that either spent time in the veterinary hospital or that had lived with animals in large outdoor cages that later tested positive for the bacteria while in the hospital. Results are back on more than 160 of the samples, Strecker said, and have identified five monkeys that were exposed. Three of the monkeys, rhesus macaques, became so ill they were euthanized. Two others are currently healthy though tests have detected antibodies to the bacteria indicating they were exposed.

People and animals exposed to the bacteria can take one day to several years to show signs of disease. Most of those exposed by contact with contaminated water or soil will never show signs of illness, Gee said, but the bacteria can hide for years in the body. Much is unknown about which people will be sickened and which won't, though diabetes and cirrhosis of the liver are among conditions that may make a person vulnerable to developing symptoms.

Burkholderia pseudomallei can cause a wide range of symptoms, from fever to localized skin infections to deadly pneumonias. For those who develop disease from the bacteria, the fatality rate can be as high as 50%. Successful treatment with antibiotics can be long and difficult in severe cases, said Henry Walke, CDC's branch chief for special pathogens.

Pat Brister, president of St. Tammany Parish, where the lab is located near homes, expressed frustration that she was learning about the 177 monkeys from USA TODAY rather than directly from Tulane. "It is unacceptable to me that I'm hearing this information from you," she said Thursday night. "It certainly raises a red flag to me that I'm not hearing everything from them."

Strecker said Thursday night that the movement of animals to the outdoor cages from the hospital is an issue known to the "Unified Command," the group of local, state and federal agencies working on the investigation and response. The parish has a representative in the group, he said.

Brister said the parish is considering holding a public meeting to help answer the growing number of questions that local residents are asking about the bacteria and the investigation.

Meanwhile, as a precaution, other research facilities across the country are testing animals they have received recently from the Tulane primate center, which breeds and supplies macaques for use in projects nationwide. In December, before the lab breach was known, Tulane sent a group of Chinese-origin rhesus macaques to an out-of-state research facility, Strecker said Tulane officials contacted the facility, which he wouldn't identify, as soon as they knew there was an issue.

"We have since learned that some of these animals have been sent on to other institutions," Strecker said. The CDC has contacted the other institutions and is helping with testing. All of the shipped animals tested so far have been negative for exposure to the bacteria. Tulane did not say how many animals were shipped.

None of these Chinese-origin macaques were in Tulane's veterinary hospital during the period of suspected contamination, Strecker said. These animals are kept in a different area of the outdoor breeding colony from most of the other monkeys at the facility, which are Indian-origin rhesus macaques, he said.

In other developments, test results released on Thursday indicate that a federal investigator was not exposed to the bacteria while investigating the lab accident at Tulane in January. The CDC said tests show her level of antibodies remain the same as they have for several weeks, indicating her exposure is not new. The inspector has traveled to an undisclosed part of the world where the bacteria is commonly found. The bacteria is mostly found in Southeast Asia and northern Australia.

Officials with the Louisiana Governor's Office of Homeland Security and Emergency Preparedness have asked for federal help investigating potential soil contamination around the facility.

Although a limited number of soil and water tests have not detected the bacteria outdoors, USA TODAY reported Sunday that studies indicate that too few samples were taken to detect what can be an elusive bacterium. Tulane says it believes the soil testing was adequate because samples were taken in areas where monkeys perch and their waste falls.

For full coverage of USA TODAY's ongoing investigation of laboratory safety and security, go to biolabs.usatoday.com.

Follow USA TODAY investigative reporter Alison Young on Twitter: @alisonannyoung.