Individual Unknown:

the use of cats in research

By Crystal Schaeffer, AAVS Outreach Director

AV Magazine Spring 2006, Individual Unknown

I have been lucky enough to share my home with several feline companions over the years. When I was young, Suzie, a grey Persian, was a beloved playmate, tolerating my game of dress up in exchange for playing her favorite pastime, catch the pink catnip mouse. Callie was a medium-haired calico who, despite her highly independent nature, loved to be in the presence of her human companions. However, she seemed to forever hold a grudge against me after I brought home Blonde, an FIV (feline immunodeficiency virus)-positive male buff tiger who once lived a rough and tumble life as a stray and who appreciated the company of Callie, despite her distaste for him. And Lexie, a three-legged white cat with brown tiger markings who suffered from an anxiety disorder and a chronic digestive malady that forced her to take several medications, always greeted me with a forward tumblesault. When I think of each of these feline companions, I have cherished memories of them and appreciate how each individual touched my life in her or his own way. Of course, all five looked very different. But all five had very different personalities and needs, too.

As an anti-vivisectionist, I think of cats who are living in laboratories. They often live in near barren environments with little stimulation and affirmative human attention. There are no sunny spots on which to lie, no special comforting corners in which to hide, no opportunity to express their individualism. I cannot imagine how confining, how stifling it must be to exist but not be considered an individual, an entitlement deserving of all, yet given only to those lucky enough to live in loving homes. This is what animals in laboratories face. They are numbers; they are ‘tools.’ They are not individuals.

The Numbers

According to U.S. Department of Agriculture (USDA) statistics kept from 1973-2004, the peak year for cat use was in 1974 when 74,259 cats were utilized in research. The most recent information available indicates that in the year 2004, over 23,500 cats were used in research and testing, and scientists reported that 9,188 of these individuals experienced pain and/or distress. (These figures do not include the tens of thousands of cats who are used in breeding colonies or dissection.)

Over the past two decades, there has been a declining trend in the use of cats in research, with numbers plateauing near 25,000 in recent years. Additionally, according to a 2004 USDA report of specific animals used in research, cats are in less demand than dogs, non-human primates, and pigs, whose numbers are well over 50,000, and guinea pigs, who are used ten times more frequently. However, it is important to note that in research areas in which the use of cats is declining, they are likely being replaced with smaller, cheaper, easier to ‘manage’ animals such as mice and rats, who do not fall under the umbrella of the Animal Welfare Act, legislation requiring specific standards to be met for the care and use of certain animals in laboratories.

‘Tools’ of the Research Trade

Although cats are utilized in research to investigate a variety of human diseases, they are especially popular in HIV and AIDS studies and are often used as models of human conditions in the area of neurology and related fields. In fact, cats have been used so often in this area that they are usually the species of choice because so much is known about their neurological functions. Unfortunately, this type of research is extremely invasive and almost always results in the euthanasia of the cats after they are subjected to gruelling vivisection procedures.

HIV and AIDS
Cats are commonly used in HIV and AIDS research due to a pair of AIDS-like feline viral diseases, feline leukemia virus (FeLV) and FIV. The use of cats is more related to logistical and practical considerations such as that "cats fulfill desired handling, housing, and availability criteria for effective AIDS models," rather than to shared disease characteristics. Cats are also relatively inexpensive (compared to non-human primates, who are also used in HIV/AIDS research) and easy to obtain, regardless of whether they were ‘naturally’ infected with FeLV/FIV or are specific pathogen-free animals whom researchers can purposefully infect as they choose.

The differences between the feline model of HIV/AIDS and the human condition vary. For example, unlike HIV, FeLV is transmitted to other cats primarily via saliva. Clinically, only 30 percent of FeLV exposed cats progress to the full-blown disease state, with the majority recovering from natural exposure. This is not the situation with human exposure to HIV. Additionally, FeLV also gives rise to a variety of disease expressions not commonly associated with AIDS. Due to significant differences between FeLV and HIV/AIDS, less emphasis has been placed on using this model.

Like FeLV, the primary route of FIV infection is by exposure to saliva. However, unlike FeLV, FIV cannot be effectively transmitted within cat populations without the presence of co-factors such as FeLV, creating a serious dilemma for data interpretation, because FeLV by itself has the ability to produce significant immunosuppression. FIV infected cats are characterized by such general clinical signs as dullness, swollen lymph nodes, anorexia, weight loss, and infections. Clinical observations of FIV infected cats do mimic those associated with HIV in humans. However, mortalities in laboratory FIV experiments are characterized by such a wide range of pathologies that the only apparent common link is FIV. In contrast to HIV, virus-specific protection against FIV is possible in cats, and a larger percentage of infected individuals survive. Additionally, as with the non-human primate SIV viruses, natural FIV infections in wild cat species are widespread but do not kill the animals.

Some HIV/AIDS research using FIV feline models focuses on drug development such as that at the Scripps Research Institute, which is investigating drug sensitivity and resistance, despite the fact that cats metabolize proteins (a potentially important drug ingredient) differently than humans. Researchers at North Carolina State University, Raleigh are conducting vaccination studies using cats who are infected with FIV vaginally, a method of transmission that does not occur naturally. Neuropathology associated HIV/AIDS research using FIV positive cats is being conducted at Tulane University and the University of Calgary, among others. And, in a much criticized project, Lawrence Mathes of Ohio State University has received hundreds of thousands of taxpayer dollars through the National Institutes of Health the past several years to addict cats with FIV to methamphetamine “to evaluate the synergistic effects of FIV infection and chronic METH with acute binges on immune function, viral interaction,” and various neuropathologies, despite the fact that cats do not get HIV and do not naturally ingest narcotics nor respond like humans as a result of exposure.

Paralysis and Spinal Cord Injury
Despite their differing locomotion patterns, cats and other animals such as dogs and rats are routinely used as models for spinal cord injuries in humans. Researchers do not use animals whose spinal cords have been damaged accidentally; rather, they induce trauma to the spinal cords of healthy cats in the laboratory. Some cats receive treatments, which may include electrical stimulation, surgical reconstruction, feline fetal central nervous system tissue grafts, and steroids. However, no effort is made to repair those cats who serve as the experimental ‘control,’ and studies can last as long as two years. Most cats are euthanized at the end of these studies to examine their brains and spinal cords.

Methods of intentional spinal cord injury (SCI) include hot water injury, scalpel or cryogenic lesioning, compressive trauma, electromechanical devices, extradural cuffs, and ‘weight-drop techniques.’ In one study conducted at Palmer College of Chiropractic in Iowa, anesthetized adult cats suffered “spinal manipulative loads” to L6 vertebrae via a wave-patterned force delivered in various durations and magnitudes equivalent to up to 100 percent of their body weight.

Other cats are injured in order to assess the degree of damage sustained to normal neurological function (i.e., their ability to walk when placed upon a treadmill, to maintain balance, to control bladder functions, etc.) or the accuracy of the method of injury in creating an animal model of spinal cord injury. For example, at the University of Pittsburgh and the University of Alberta, scientists are purposely inflicting spinal cord injuries on cats who are subjected to electrical stimulation and then forced to try to bear weight and/or walk on their paralyzed or partially paralyzed hind limbs. In another study at the University of Utah, researchers investigated the potential restoration of the peripheral nervous system in individuals suffering from SCI, using selective stimulation of the cat sciatic nerve as a model. Seven cats were anesethized, and the muscles of their right legs were separated and the sciatic nerve exposed so that electrodes could be attached to the area. While the researchers were somewhat successful in stimulating movement, the practicality and risk of conducting such a procedure on a person lessen the impact of the results, especially since the anatomy and physiology of cats differ greatly from humans.

Other Areas
Cancer, Parkinson’s disease, genetic disorders, and epilepsy are some of the other areas in which cats are used as models for human conditions and ailments. Felines are also used as models for sleep and brain function, including sleep disorders and the effects of medication on sleep. Several studies of breathing patterns during sleep to understand sleep apnea in humans have been conducted on cats whose brain stems have been severed.

As with many of the studies mentioned above, in research investigating hearing loss, scientists intentionally impair cats’ ability to hear, or breed white cats who are genetically predisposed to deafness. In one study of sound localization conducted at the University of Wisconsin, Madison, scientists compared the accuracy of restrained cats to those who were permitted to move their heads, in order to study the correlation of eye position and auditory responses. Cats have also long been the subjects of vision research and visual impairments such as ‘cross eye’ and ‘lazy eye.’ Often, the visual problems are not naturally occurring but instead induced by covering the eye with material or stitching the eye shut, with kittens frequently being used to monitor visual development. At the University of California, San Francisco, cats have tetrodes, bundles of electrodes that aid in the recording of brain activity, surgically implanted on their heads in an effort to study cross eye, lazy eye, and neurological disorders brought about through stroke. At the conclusion of the experiment, the cats are killed and their brains dissected for further analysis.

Conclusion

Cats are utilized in a wide variety of research disciplines and are popular as models for human conditions, including HIV/AIDS. But in order to conduct these experiments, cats are subjected to many troubling procedures, particularly in the vast field of neurological research. In laboratories, animals such as cats are repeatedly used in unnecessary investigative studies, reduced to being ‘tools’ of the research trade and numbers as data in charts and journal articles, despite the existence of alternative testing methods.

As I pat my feline companion Ty, who has just sat back on his haunches and stretched upright, batting his front paws like a little bear, stopping only when I scoot over to share my seat, I am again reminded of how this individual with a big personality enriches my life. Moreover, I truly believe Ty enjoys his life, not just because he has the freedom to do what he wants but rather because he has the freedom to be who he wants. I can think of no better inspiration to continue advocating for animals in laboratories.

Schaeffer, Crystal. (Spring 2006). AV Magazine. Pages 10-13.

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