US-based scientists are using more non-human primates in research than ever before, according to data from the United States Department of Agriculture (USDA).

As reported by animal welfare science journalist David Grimm, government documents released in late September show that the numbers of primates used for scientific activities rose 22 percent between 2015 and 2017. In 2017, the total number of primates included in biomedical investigations was 75,825. Of these, 44,624 were used in studies that did not involve pain, 30,057 were included in activities that inflicted pain but offered drug-based pain relief, and 1,144 experienced pain with no relief. An additional 34,369 were held at various facilities but not used in research.  

Compared with the 2010 figures, demand for cats, dogs, pigs, and all other animals – excluding mice and rats, which are not subject to the same regulations – has been declining or holding steady at the most. Indeed, recent advances in computer modeling and the advent of innovative cell and tissue-based body system models – known as "organs-on-a-chip" – would imply that, ethics aside, the need for animal testing should be diminishing. Last year, the FDA announced a multi-year research agreement with an organ-on-a-chip company to develop and test their platform. The agency plans to first assess how well a liver chip can mimic the real deal during evaluations of medicines, disease-causing food-borne bacteria in foods, and chemicals in personal care products. The initiative will soon be expanded to include kidney, lung, and intestine chip models.

“Many of these tissues or cells are from human origin, which researchers would agree are often more relevant than animal cells,” Erin Hill, president of the Institute for In Vitro Sciences, a nonprofit laboratory that develops non-animal testing methods, told Healthline in February. “These technologies hold the promise of being more human-relevant and predictive and are often faster – and therefore cheaper – than animal models.”

In a report released just days before the USDA’s tallies, the National Institutes of Health (NIH) wrote that the demand for the most commonly used primates – rhesus macaques, marmosets, and baboons – is likely to continue growing.

The NIH stated that the increasing demand for primates stems largely from research groups focused on addiction, HIV and AIDS, the brain, and Alzheimer’s disease who want a model as close as possible to humans.

In response to the ongoing public outcry over animal testing, Cindy Buckmaster, board chair of the animal research advocacy group Americans for Medical Progress, told Science: “The public wants more cures, but fewer animals. They can’t have it both ways.”

[H/T: Science Magazine]