April 24 Marks World Day For Laboratory Animals: Raising Awareness To End Animal Testing

Photo credit: ADI

World Day for Laboratory Animals (WDLA), observed on April 24, was established in 1979 by the UK’s National Anti-Vivisection Society, now known as Animal Defenders International (ADI). The day continues to draw attention to the more than 100 million animals who suffer in laboratories worldwide each year.

According to the most recent U.S. government annual report summary, 42,880 dogs; 12,004 cats; 115,043 rabbits; 134,086 guinea pigs; 104,808 nonhuman primates; 147,378 other mammals; and 45,005 pigs were used for experimental purposes. This figure does not include the countless mice and rats who are also subjected to testing.

Meanwhile, progress is slowly being made to address animal experimentation. The UK government has set out a “roadmap” to end certain tests. In the United States, ADI has sent a letter to the United States Pharmacopeia (USP), urging the organization to phase out animal-based testing in pharmaceutical safety assessments. Letters to the Food and Drug Administration and members of Congress will follow, encouraging new legislation to bring testing in line with modern science.

“Right now, we stand at a critical time for the elimination of animal experiments, with the UK government setting out a roadmap for ending certain tests, such as the 100+ year old pyrogen test on rabbits and the forced swim test on rats, banned,” explained ADI Founder and President Jan Creamer.

“The U.S. Food and Drug Administration (FDA) has outlined an even more ambitious ‘roadmap’ to end outdated animal methods, although with less clear-cut targets. The Colombian government is working on the compulsory replacement of certain tests (under a ban on cosmetics testing on animals secured by ADI). As these measures come together, we could be standing on the brink, or the biggest shift away from animal experiments, the world has ever seen.

“Critical to this progress is the increasing acceptance across science, regulators, and governments, that animal experiments are unreliable and outdated science.”

The letter focuses on pyrogen testing, used to detect fever-causing contaminants in medicines, where outdated methods such as the Rabbit Pyrogen Test (RPT) and horseshoe crab–derived Limulus Amebocyte Lysate (LAL) test are still referenced. ADI highlights that these methods present scientific limitations and rely on animal use, despite the availability of more advanced alternatives.

ADI is calling for a transition toward non-animal, human-relevant testing approaches, including the Monocyte Activation Test (MAT), which uses human immune cells, and recombinant technologies such as recombinant Factor C (rFC), a synthetic alternative to horseshoe crab blood. These methods are widely recognized for their improved reliability, sustainability, and relevance to human biology.

The proposal emphasizes that regulatory frameworks in Europe have already removed the Rabbit Pyrogen Test in favor of modern in vitro methods, demonstrating that such a transition is both achievable and effective. ADI argues that updating USP standards would help align the United States with international scientific progress and support global harmonization of pharmaceutical testing.

Sadly, animals continue to be used even though we already understand the critical differences in how species respond to chemicals, drugs, and other products. Results can be influenced simply by an animal’s presence in a laboratory, as well as by factors such as age, diet, and even bedding material. Findings have also been shown to vary between laboratories.

Due to species differences, animals often respond differently to substances such as drugs, and are therefore an unreliable way to predict effects in humans. For example, more than 90% of drugs that show promise in animal trials fail in human trials. Human diseases that do not naturally occur in animals are artificially created; these “models” do not accurately replicate human conditions and can produce misleading results.

There is no justification for continuing to use animals in experiments when so many effective, reliable, and humane alternatives are available.