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Senior officials at the US National Institutes of Health (NIH) have concluded that a major chimpanzee research centre did not violate the biomedical agency’s breeding moratorium, despite 130 infants being born at the centre to NIH-owned parents between 2000 and 2010 (see 'Lab bred chimps despite ban').

The assessment, carried out by the NIH’s Office of Extramural Research and obtained by Nature under the US Freedom of Information Act, argues that the New Iberia Research Center (NIRC), part of the University of Louisiana at Lafayette, did not violate the 17-year-old moratorium for two reasons. First, its 3–4% mortality rate during the period matched those of other NIH-supported chimpanzee centres. Second, the centre did not make additional charges to the NIH as a result of the births.

“Based on…a decrease in census and no increase in cost…NIRC has not violated the [NIH] moratorium,” the document states. It also argues that the NIRC’s contraception programme — which it says led to a 13% average annual conception rate in the years leading up to 2010, down from 50% in 1995 — “is within acceptable limits” for preventing pregnancy in the federally owned colony. It notes that the NIRC has assumed ownership of the infants, as is required under its written agreement with the NIH.

The Louisiana centre houses approximately 350 chimpanzees, of which the NIH owns 111. The agency pays the centre more than US$1 million a year to maintain its own animals and to support about 100 other chimps. Because of the high costs of lifetime maintenance of chimpanzees, the NIH has had a breeding moratorium in place since 1995. During the period in question, the NIRC used contraceptive methods that included: housing males and females separately when social groupings allowed; performing vasectomies on selected males; and using the implantable progestin Norplant and intrauterine devices.

Ongoing efforts

James Blanchard, the interim director of the NIRC, said in an email this week that the NIRC’s conception rate for the past two years has been less than 1%. This, he wrote, “is a reflection of our ongoing efforts to provide responsible management of the NIH chimpanzee colony.”

But Kathleen Conlee, vice-president for animal-research issues at the Humane Society of the United States, which first learned of the births through public-records laws, says that the criteria used by the NIH to determine whether the ban was breached — whether the centre’s costs or total census increased — are “unacceptable”. “How NIH has interpreted whether the NIRC bred chimpanzees is very misleading,” she says. “It should be based on whether breeding occurred.”

Conlee notes that an NIH working group is now determining criteria for the agency’s funding of future chimpanzee research, responding to a report made last year by the US Institute of Medicine that concluded that invasive research is largely unnecessary. In addition, Congress is considering a bill that would end invasive research in great apes (see 'Bill to end US chimp research advances'). In this context, Conlee says, NIH officials “are driven to not appear as if they weren’t properly monitoring the situation”.

But Gregory Kaebnick, a bioethicist at the Hastings Center in Garrison, New York, says that the drop in the reproduction rate during the moratorium indicates that “the chimps were breeding, but the NIRC arguably was not breeding them”.

However, he adds, “Though what NIH is doing here is comprehensible, within the letter of the law, there’s a certain amount of foot-dragging. Ultimately, they need to come to terms with the larger ethical debate.”