A prestigious laboratory in Texas already under federal investigation after inspectors determined it didn't do enough to prevent the suffering of primates is facing more scrutiny after animals in another study were found dead.

In the latest probe, the U.S. Department of Agriculture's Animal and Plant Health Inspection Service cited the Galveston National Laboratory last month for problems including improper data collection regarding animal observations and failure to promptly notify an attending veterinarian of an animal's death. This came after federal inspectors learned that 19 guinea pigs died during a study at the lab, one of the nation's leading research facilities seeking vaccines for some of the most lethal diseases.

"The institution has taken appropriate corrective actions to prevent recurrence," the National Institutes of Health said Friday in a written statement.

Findings in a USDA inspector's report echo concerns included in the federal investigation that the National Institute of Allergy and Infectious Diseases launched last year. A preliminary report issued last year in that probe found test animals weren't properly observed. If left unobserved the animals can suffer from the effects of diseases like anthrax and Ebola before being euthanized.

"This problem is not limited to one project or even to one species," Michael Budkie, executive director of Ohio-based Stop Animal Exploitation Now, said Friday. "Basically what this is showing is that the problems are systemic."

But officials at the University of Texas Medical Branch, where the lab is located, deny any far-reaching problems and say the welfare of animals there is a primary concern.

"We deal with some of the most dangerous diseases on the planet," said Toby Boenig, UTMB vice president and chief compliance officer. "It's our intention to intervene before the animal dies from the disease."

Studies at the lab are often conducted to determine how effective a vaccine may be against a pathogen, lab administrators say. A series of protocols are used to maintain strict controls on a study.

Some studies may evaluate a vaccine against the late stages of a disease in an animal. Others may determine the effect on another species when a vaccine is introduced earlier.

"When you get to a certain stage of a disease, at what point can you still use a vaccine and save lives?" asked Dave Niesel, UTMB chief research officer.

Niesel mentioned the Liberian man who in 2014 was discharged from a Dallas hospital because staff didn't realize he had been stricken with Ebola. Treatment was delayed and the man grew sicker as the disease spread through his body, Niesel said. "So one of the key questions the world wants to know is where along the progression can lives still be saved?" he said.

The preliminary report from the federal investigation of the Galveston lab found a variety of procedural errors with the primate study conducted at the facility. The lab had a contract with the National Institute of Allergy and Infectious Diseases to develop a strain of the Marburg virus that could be used on Macaque monkeys to find a cure. Eight monkeys were found dead in their cages in 2014; four others were euthanized.

The Marburg virus has similarities to Ebola and is among the most virulent pathogens known to infect people, according to the World Health Organization.

The federal probe's preliminary report found dozens of irregularities, some considered minor and others more serious. They ranged from incomplete training files for some employees to data that was not recorded and operating procedures that were not followed.

The federal investigation is ongoing and penalties could range from federal action that ensures compliance, such as additional training for employees, to loss of funding from federal agencies.

Lab officials acknowledge minor infractions occurred and said they have been corrected. But they argued the majority of claims, including that animals were allowed to suffer, were unfounded.

Niesel said in the wake of findings from last year, the lab has hired additional staff and made a series of changes, including increased observation of animals. Those changes had not been fully implemented when the guinea pigs died late last year.

A spokeswoman for the National Institutes of Health, which contracts with many labs on animal testing, did not respond to questions about whether the number of deaths at the Galveston lab is consistent with those at other labs.

"This is not frivolous work. We are actually trying to stem the tide against some of the world's most dangerous viruses," said UTMB spokesman Raul Reyes, later adding, "We never set out to intentionally harm an animal."

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