Two monkeys have died at the Harvard Medical School’s New England Primate Research Center in the past three months, resulting in the suspension of all new experiments at the Center indefinitely.

These most recent deaths boosted the total number of primates deaths in Harvard research facilities to five in the past 19 months, leading Dean of the Medical School Jeffrey S. Flier to halt experimentation at NEPRC.

A cotton-top tamarin monkey died Sunday at the NEPRC, the Boston Globe reported Wednesday. The cause of death is under investigation. According to the Boston Globe, the monkey did not have a water bottle in its cage, which may have been a factor in its death.

In December, a squirrel monkey died from dehydration at the NEPRC, located in Southborough. In response to the squirrel monkey’s death, the United States Department of Agriculture cited the Medical School in a Feb. 3 report for failing to adhere to the Animal Welfare Act.

The report states that an additional monkey was also dehydrated but responded to treatment and recovered.

In the report Paula S. Gladue, a veterinary medical officer inspector who conducted the Jan. 31 inspection, cites NEPRC for failing to ensure that the monkey’s water dispenser was functioning properly.

USDA spokesperson David Sacks wrote in an email to The Crimson that the recent primate deaths have put the Medical School on the USDA’s radar because the recent deaths are “not the norm” at research facilities. “We are very concerned with this string of monkey deaths,” Sacks wrote.

Sacks added that the USDA is currently conducting an investigation and will determine the penalty for the Medical School. A USDA citation can result in a warning letter to the offending institution or a fine of up to $10,000.

“These are indeed serious non-compliances at Harvard, and the university knows it needs to do a much better job of ensuring the welfare of its animals,” Sacks wrote. “We will continue to closely monitor their research facilities in the days and months ahead.”

Flier said that the animal deaths are “absolutely unacceptable, deeply regrettable and personally disturbing to me.” Flier also said he plans to implement a three-step plan to correct the failing protocol.

In addition to freezing new research on primates, Flier will create a team of veterinary staff and supervisors who will monitor animals and procedures more frequently.

Additionally, the Medical School is commissioning an independent review committee of outside experts to assess and advise the NEPRC’s corrective efforts.

In October of last year, NEPRC was cited by the USDA for multiple violations of the Animal Welfare Act—namely the Oct. 2011 death of a primate that died soon after escaping from its cage. The primate was then captured with a net by NEPRC staff, and died after undergoing an imaging procedure. At a separate research facility, a primate died in Feb. 2011 due to anesthesia overdose.

In June 2010, a primate was found dead in a cage after it allegedly went through a mechanical washer.

—Staff writer Nathalie R. Miraval can be reached at nmiraval@college.harvard.edu.

—Staff writer Rebecca D. Robbins can be reached at rrobbins@college.harvard.edu.