Animal use in research has long been a highly controversial and veiled field, particularly in the United States. In the 2010 fiscal year alone, an estimated total of 1,134,693 research animals covered under the Animal Welfare Act were reported to have been used within the United States. (See http://www.aphis.usda.gov/animal_welfare/efoia/downloads/2010_Animals_Used_In_Research.pdf). However, the Animal Welfare Act excludes coverage of birds, mice, and rats, species that comprise the majority of the research animal population, making 1,134,693 only a fraction of the total animals used in research in 2010. Additionally, the proliferation of FDA-regulated medical products has made it increasingly difficult to deny the influence of biomedical animal research in our daily lives. Despite its presence in the life of the average consumer, animal testing remains a sensitive area due to the ethical concerns its raises in valuing the human lives and comfort over that of animals. Animal research as a practice is allowed by trust of the public that researchers will use such privileges for medical advancement and benefit of mankind. As such, varying aspects of animal use in research are regulated by multiple governmental bodies such as the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS), the National Institutes of Health (NIH), and the Food and Drug Administration (FDA).
This paper will examine the various federal regulations on animal biomedical testing within the United States as well as the industry’s standards and trends. The first four sections examine the FDA requirements for medical products in the United States, federal animal welfare regulations, the general structure of a research facility, and industry regulations for animal use. The second half of this paper examines the species of animals used in research as well as their source of purchase. Accepted methods of euthanasia per species are also examined. By comparing the options available for a research facility to animal use regulations in the United States, it is hoped that the structure of animal welfare in the laboratory can be understood from both economic and legal motivations that influence animal research use today.
I. Medical Research Animals
Most biomedical animal testing in the United States focuses around preclinical testing. Preclinical trials are usually completed in order to determine the safety of a medical product, drug or medical device, before progressing to human trials, known as clinical trials. Despite advances in non-animal testing, many products today still use animals as an initial means of testing.
A. Preclinical and Clinical Trials
For both drugs and devices, the process of developing a medical product from conception to market in the United States will often involve multiple trials before receiving Food and Drug Administration (FDA) approval for sale. For the most part, preclinical biomedical trials for both drugs and devices aim to determine the safety of the product before progressing to human testing in clinical trials. While some products are able to pass initial testing with pre-existing data, many products today are still tested using animal models prior to being used in human trials. The primary reason for the use of animal subjects lies in the difficulty of effectively and realistically simulating complex living organisms through alternative means. While most products are ultimately geared for human use (some tested products are for use in domestic animals), preclinical trials serve the function of ensuring that a product is safe enough to be tested with a human subject. Once the medical product is deemed safe and efficient for its purpose by the FDA, researchers are allowed to continue testing in human clinical trials. (See Drug Development and Review Definitions at http://www.fda.gov/Drugs/DevelopmentApprovalProcess/HowDrugsareDevelopedandApproved/ApprovalApplications/InvestigationalNewDrugINDApplication/ucm176522.htm).
B. FDA Requirements for Medical Devices
Medical devices are defined by § 201(h) of the Federal Food, Drug and Cosmetic Act (FDCA). Medical devices encompass typical implanted devices such as stents or pacemakers, but can also include products such as surgical tools and prosthetics.
FDA requirements that a medical device must fulfill before arriving to market differ depending on their classification. Dependent on the classification, a medical device may be subject to more regulations. Classification of a medical device is usually affected by the risk posed to the user, its intended use, and also its indications for use. An intended use is defined by the FDA as referring to ‘the objective intent of the persons legally responsible for the labeling of devices’ that may be determined by the labeling, advertising, or statements of those persons or their representatives. 21 CFR § 801.4. It is important to note that the intended use of a product may change after it has already reached the market. More importantly, classification of medical devices is largely affected by the risk posed to the patient, requiring more regulatory controls the more risk-based the device.
There are three regulatory classes under the FDA for medical devices. Medical devices are subjected to an increasing extent of regulatory control as they are categorized between Class I, Class II, and Class III respectively. Accordingly, Class I devices tend to be devices that pose little risk to the patient while Classes II and III increase in risk. All classes of medical device are subject to baseline requirements of the FDA, regardless of their classification. (For more information, see "Classify Your Medical Device" at http://www.fda.gov/medicaldevices/deviceregulationandguidance/overview/classifyyourdevice/default.htm).
Medical devices are differentiated from drugs as being defined as not achieving their primary intended purpose through chemical action within or on the body and are not dependent on being metabolized by the body to achieve their primary intended purpose. FDCA § 201(h).
C. FDA Requirements for Drugs
Drugs are usually evaluated by the FDA’s Center for Drug Evaluation and Research (CDER). Drug trials for new medications are generally conducted in two mammalian species (one non-rodent) before they can progress to human clinical trials. With as clinical trials progress, the focus of the research shifts from determining the safety of the drug to also include studying whether it is effective for its purpose. (See "Drug Development and Review Definitions" at http://www.fda.gov/drugs/developmentapprovalprocess/howdrugsaredevelopedandapproved/approvalapplications/investigationalnewdrugindapplication/ucm176522.htm). Following a company’s preclinical and clinical trials, the FDA reviews submitted data for approval to determine whether to drug’s proposed benefits outweigh its risks for use. Drugs are continually monitored after entering the market for potential new adverse reactions. (For more information, see "How FDA Evaluates Regulated Products: Drugs" at http://www.fda.gov/AboutFDA/Transparency/Basics/ucm269834.htm).
III. Federal Regulations and Agency Standards on Animal Testing
Regulations on animal testing are set forth by several different sources. For the most part, most federal regulations are established and enforced by two main agencies: the United States Department of Agriculture’s Animal and Plant Health Inspection Services (APHIS) and the Food and Drug Administration (FDA). The National Institutes of Health (NIH) also sets forth regulations through the Public Health Service Policy, but these do not necessarily apply to all research institutes. As agencies serving different public interests, regulations stemming from each agency tend to serve a different purpose but have an influence on animal biomedical testing standards.
A. The USDA: Animal Welfare Act and Animal Welfare Regulations
Most federal animal research regulation stems from the Animal Welfare Act (AWA) and additional regulations under Title 9, enforced by the United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS). The Act and regulations maintain standards for animal care and use in multiple different industries, including biomedical research. In addition to federal regulation, researchers are also responsible for complying with state and local laws dependent on the jurisdiction. It is important to note that, while the Act defines the term ‘animal’ as to include most species of warm-blooded animals used in research alive or dead, species that constitute the majority of animals used in research such as birds, rats, and mice are excluded. Several cases have arisen from this exception in an effort to broaden the scope of the AWA to cover these excepted species, particularly mice and rats which constitute the overwhelming majority of research animals. (See Alternatives Research & Development Foundation v. Glickman, 101 F.Supp.2d 7 (D.D.C.,2000), holding that the AWA does not grant the USDA ‘unreviewable discretion to determine what animals are covered under the AWA').
The Act and regulations establish baseline humane standards to be used within research facilities in the United States. Animal biomedical research is regulated from multiple aspects within the Act, from the composition of the staffing within the institution to the minimum standards of veterinary care and housing for animals. The most notable roles within any animal biomedical research institute are listed and defined within the act as the Institutional Official (IO), Attending Veterinarian (AV), Institutional Animal Care and Use Committee (IACUC), and the Principal Investigator (PI).
Institutional Official – 9 C.F.R. § 2.30
The Institutional Official is defined by the regulations for legal purposes as the individual authorized to commit that the research facility is in compliance with the requirements of the Animal Welfare Act.
Attending Veterinarian - 9 C.F.R. § 2.33
Research facilities are required by 9 C.F.R. § 2.33 to have an Attending Veterinarian (AV) on staff who is largely responsible for ensuring appropriate veterinary care for facility animals. The AV is expected to also work with the Principal Investigator (PI) to minimize pain and distress to animals, ensuring adequate pain relief and, if appropriate, euthanasia if pain or distress cannot be relieved. Given these responsibilities, the AV must be provided with enough authority within the facility to ensure that adequate veterinary care is provided at all times to that animals from all aspects of animal care and use. Adequate veterinary care is defined by the Act as “what is currently the accepted professional practice or treatment for that particular circumstance or condition." Additionally, the AV must be a voting member of the Institutional Animal Care and Use Committee (IACUC). It is important to note that the Act includes a limitation in which recovered animals may not be used in more than one major operative procedure unless justified by scientific reasons by the PI, as a routine procedure, or for the well-being of the animal as determined by the AV, unless otherwise individually approved by the Administrator of the USDA’s Animal and Plant Health Inspection Service (APHIS). While the Act does provide minimum standards for housing such as type of enclosure, temperature, feeding, watering, and exercise provided, much discretion is ultimately left to the AV dependent on what they determine to be for the well-being of the animal, rendering the majority of the Act’s baseline restrictions much more flexible than they would appear.
The facility itself is responsible for ensuring that there are adequate personnel, equipment, and methods to provide adequate veterinary care to animals. Guidance must be provided to principal investigators and other personnel regarding the care and use of the animals of the facility in terms of ‘handling, immobilization, anesthesia, analgesia, tranquilization, and euthanasia. 9 C.F.R. §2.33 (b)(4). Finally, daily health observations for animals and adequate pre- and post-procedural care are mandatory.
Institutional Animal Care and Use Committee (IACUC) – 9 C.F.R. § 2.31
Each research facility is required to appoint an IACUC to review the facility’s animal program and procedures. Membership is determined by the Chief Executive Officer of the research facility. It is important to note that at least one member of the IACUC must be a Doctor of Veterinary Medicine who has at least some responsibility for activities involving facility animals. The IACUC is largely responsible for review and inspection of the facility’s animal program, including any complaints regarding the care and use of facility animals. Additionally, the IACUC has the power to modify, approve, suspend or withhold approval on activities related to the care and use of facility animals, including methods of research. The IACUC reports its findings to the Institutional Officer regarding the facility’s compliance or violations of Act requirements. A plan report with scheduled dates for correction must be issued for noted program deficiencies. If the deficiency remains uncorrected, APHIS and any Federal agency funding the research must be notified within 15 business days, making this role largely self-regulating within research facilities. Ideally, the IACUC ensures that studies are using only as many animals as needed, responsibly, and that the proposed method is humane.
Principal Investigator - 9 C.F.R. § 2.31
The Principal Investigator (PI) is responsible for the research proposal involving animals. The PI may not necessarily be an employee of the research facility. Additionally, the PI is capable of providing the IACUC with written justifications for any research activity noncompliant with the Act which the IACUC may or may not approve. The proposal must also meet the listed requirements for approval. Most importantly in terms of animal welfare regulations, these requirements mandate that ‘procedures involving animals will avoid or minimize discomfort, distress, and pain to the animals’ § 2.31 (d)(1)(i) and that alternatives will be considered to procedures that may cause more than momentary slight pain or distress to the animals § 2.31(d)(1)(ii). Procedures should not unnecessarily duplicate previous experiments § 2.31 (d)(1)(iii) and that, unless excepted by scientific reasons, required as determined by the attending veterinarian or other special circumstances, no animal should be used for more than one major operative procedure from which it is allowed to recover § 2.31.(d)(1)(x).
A proposal for any activity involving animals must include:
- Identification of the species and the approximate number of animals to be used; §2.31 (e)(1)
- A rationale for involving animals, and for the appropriateness of the species and number of animals used; § 2.31 (e)(2)
- A complete description of the proposed use of the animals; § 2.31 (e)(3)
- A description of procedures designed to assure that discomfort and pain to animals will be limited to that which is unavoidable for the conduct of scientifically valuable research, including provision for the use of analgesic, anesthetic, and tranquilizing drugs where indicated and appropriate to minimize discomfort and pain to animals; and § 2.31 (e)(4)
- A description of any euthanasia method to be used. §2.31 (e)(5)
All facilities that keep animals included under the scope of the AWA must be licensed or registered with APHIS. In addition to internal regulation mandated by the AWA, APHIS is also capable of conducted unannounced compliance inspections of any licensed or registered facility. Facility managers or owners are notified of any deficiencies found by the inspector. Inspectors may determine whether there is adequate housing conditions, sanitation, and veterinary care within the facility. Additionally, inspectors may also review animal records for identification, acquisition, and disposition to ensure accurate and complete documentation. Violations of a serious nature or uncorrected repeat citations in future inspections may lead to license suspension, confiscation, and penalties. (See "Compliance Inspections" at http://www.aphis.usda.gov/publications/animal_welfare/content/printable_version/fs_compliance_inspection.pdf).
B. The FDA: Good Laboratory Practice Compliance
While the AWA is enforced through the USDA, the FDA also regulates animal biomedical research in some aspects. It is important to remember that the purpose of the FDA is to protect the public health by ensuring that medical products are safe, effective, and accurately represented to the public. Consequentially, while the USDA focuses primarily on the welfare of the animals within the facility, the FDA’s regulation of research facility works to prevent the falsification of results and data to ensure products entering the market are safe and effective. The FDA’s regulatory jurisdiction includes, and is not limited to drugs, biologics (e.g. vaccines, blood products, tissue products, etc.), medical devices, and veterinary products. (See http://www.fda.gov/AboutFDA/Transparency/Basics/ucm194879.htm).
21 C.F.R. § 58 focuses on good laboratory practice (GLP) for nonclinical laboratory studies, which includes both in vitro and in vivo experimentation. Whereas in vitro (in glass) usually refers to experiments conducted in an isolated environment such as test tubes and petri dishes, in vivo (in living) refers to experiments conducted in living subjects, including animals. Much like the AWA and the USDA, the FDA is capable of sending its employees to conduct facility inspections to ensure compliance with good laboratory practices. Similarly, GLP standards include several personnel requirements for a research facility, including training and education standards for employees. More importantly, GLP requires that a facility have a quality assurance unit responsible for ensuring compliance with GLP standards for each conducted study.
In terms of animal care, GLP standards mandate standards for housing, such as sufficient rooms for any necessary quarantine, appropriate ventilation, and sanitation. Facilities that house animals are expected to ensure a clean environment free of animal waste, vermin, odors, and disease. Newly acquired animals must be isolated and evaluated for health. GLP standards also require that animals be free of any diseases or conditions that could interfere with results of a study (note that this is largely dependent on whether a study focuses on a pre-existing condition or wound). Any water or feed provided to animals must be analyzed periodically to ensure that there are no contaminants. (See 21 C.F.R. § 58 et seq. at http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRsearch.cfm?CFRPart=58).
GLP standards focus mostly on the documentation for a facility to prevent falsification or inaccuracy of results. The concept ensures that there is a paper trail for any and all procedures done to animals, including the quality of their feed. While the focus of these standards is to ensure that a safe product is developed, there is also a secondary effect for animal care within facilities in which records may show the quality of animal care given. With full compliance, most data about any individual animal’s health status and history in a facility should be traceable in documentation from arrival to death.
It is important to note that not all studies conducted within research laboratories are required to be GLP studies. Not all testing facilities may be GLP-certified. GLP standards are meant to encompass “studies that support or are intended to support applications for research or marketing permits for products regulated by the Food and Drug Administration." GLP standards for documentation, however, are still recommended as a standard testing facilities should strive to uphold regardless of the type of study as a good practice.
C. The NIH: Public Health Service Policy on Humane Care and Use of Laboratory Animals
The Public Health Service Policy on Humane Care and Use of Laboratory Animals implements the Health Research Extension Act of 1985, directing the Secretary of Health and Human Services to set forth guidelines for the proper care and use of animals in research. (See Introduction at http://grants.nih.gov/grants/olaw/tutorial/intro.htm).
The Office of Laboratory Animal Welfare (OLAW), located within the National Institutes of Health (NIH), interprets and enforces the Public Health Service (PHS) Policy. The PHS Policy applies to any use of live, vertebrate animals used in activities supported or conducted by the PHS. Note that, unlike the AWA, this would mean that the PHS Policy has broader protection to include species like mice, rats, birds, and reptiles, although this protection only extends to activities funded by or conducted by the PHS. PHS agencies include agencies such as the Center for Disease Control and Prevention and the FDA. Any research facility that forms a contract or receives a grant from the PHS would also fall under the scope of this policy. Much like the AWA, the PHS Policy also puts facilities in a position to self-regulate by self-reporting and monitoring with an internal committee. Failure to do so could result in withdrawal of funding.
The PHS Policy also relies on the Guide for the Care and Use of Laboratory Animals (discussed below), a widely-known guide within the industry, for its regulations mandating that it be used as a basis for a facility’s animal care and use program. Compliance and consistency with the AWA and American Veterinary Medical Association Guidelines on Euthanasia are also requirements of the PHS Policy. The PHS Policy extends to various aspects of facility management, including the veterinary care program, staffing and training, disaster planning, and animal housing specifications.
In order to receive funding from the PHS, the institution must have a written Assurance which is submitted to OLAW in order to demonstrate that their facility is adequate to the PHS guidelines. These Assurances vary in terms of the length of time before their expiration, after which the institution must renew their Assurance in order to continue to receive funding. Without an approved Assurance, no funding or PHS-conducted research is permitted to continue at that facility. Although the PHS Policy lacks the force of law, there is still an incentive for some research institutions to comply with its standards.
Facilities are expected to submit yearly reports to OLAW as well as notifications of any serious policy violations. Yearly reports are expected to contain any changes in the facility’s accreditation status, animal care and use program, and IACUC.
The Public Health Service Policy on Humane Care and Use of Laboratory Animals is available at http://grants.nih.gov/grants/olaw/references/PHSPolicyLabAnimals.pdf.
D. State Anti-Cruelty Laws
State anti-cruelty laws in application to medical research depend on jurisdiction. Some states exempt scientific research from state action for animal cruelty, although conditions for these exemptions may vary. For example, while Oregon and Maryland exclude scientific activities entirely from the scope of state anti-cruelty laws, Texas and Kansas law require a showing that such experiments are “bona fide." A few states do not specifically exempt scientific or medical research from their animal cruelty provisions such as Minnesota and Wyoming. However, these activities would likely not meet the required mens rea for intentional cruelty. In any event, a successful prosecution for animal cruelty under state law for biomedical research is unlikely. In Taub v. Maryland, the Maryland Court of Appeals held that the “legislature recognized that there are certain normal human activities to which the infliction of pain to an animal is purely incidental and unavoidable…” to which cruelty laws do not apply. Moreover, the court found that the regulation by the federal Animal Welfare Act and National Institutes of Health places animal research beyond the scope of Maryland state law. Taub v. Maryland, 296 Md. 439 (Md.,1983). It is also important to note that, given the disceet nature of the animal research industry, it is unlikely for these types of cruelty cases to arise unless reported by someone working within the industry. In Taub v. Maryland, the initial investigation of the laboratory was based off information provided by a former laboratory employee. Note that the PHS Policy does not obviate state law that has stricter standards for animal welfare. (See http://grants.nih.gov/grants/olaw/references/phspol.htm#PublicHealthServicePolicyonHumaneCareandUseofLaboratory).
IV. Self-Imposed Industry Standards for Animal Testing: AAALAC and The Guide
As noted with the AWA, most regulation of animal testing facilities is internal with random compliance inspections from external parties. Biomedical animal research is still a tight-knit industry in which reputation carries weight. In addition to federal standards, the organizations within the industry itself have produced their own standards for animal care and use. While these standards may not hold the same legal authority as those mandated by the USDA and FDA, individual facilities risk losing their reputation in violation of these standards, particularly for facilities that rely on study sponsors for business. Given the relative amount of freedom that research laboratories are accorded in the AWA, self-imposed industry standards may help in guiding a facility by providing baseline accepted and recommended practices. As a result, several private organizations within the industry formed to provide accreditation or certification programs in order to promote certain standards of animal care. Such programs help to distinguish institutions as quality organizations and aid to bolster the reputation and credibility of certified facilities. One of the most well-known accreditation programs within the industry is the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).
A. Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC)
AAALAC uses Three Primary Standards in evaluating facility animal care and use programs internationally. Of the three, the most well-known within the American preclinical industry is the Guide for the Care and Use of Laboratory Animals (commonly referred to as “the Guide”). The Guide is published by the National Research Council, with the most recent revision being in 2011. The other two primary standards used by AAALAC consist of the Guide for the Care and Use of Agricultural Animals in Research and Teaching and the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes. It is important to note that participation in AAALAC’s accreditation program is not mandatory for facilities, but acts as self-imposed industry regulation in addition to local and federal guidelines. Despite this, AAALAC’s accreditation program has become well-known within the animal research industry, particularly with the larger academic and commercial institutions.
Facilities apply voluntarily for accreditation with AAALAC. Once it is determined that a facility has an accreditable animal care program, AAALAC representatives are dispatched to the facility for an on-site inspection. The AAALAC’s Council on Accreditation then makes the final decision as to whether the institution will be accredited. Following award of an accreditation, the institute must submit annual reports each year providing updated program information, detailing any changes to the facility’s animal care and use program. On-site inspections from AAALAC are conducted every three years for accreditation renewal.
2. Animal Care Standards
The Guide itself includes several chapters on various aspects of animal care such as ethics, staffing, training, and veterinary and facility standards. It also includes species-specific requirements and recommendations for animal housing and environments. It is important to note that there is a difference between regulations listed in the Guide as ‘should’, ‘must’, or ‘may’. (See p. 8 in The Guide). Whereas ‘must’ indicates a mandatory AAALAC requirement, ‘should’ indicates that the regulation is a strong recommendation but may be waived if circumstances justify. ‘May’ indicates a suggestion to be considered by the facility. Thus, the Guide provides several guidelines of varying strengths much like the AWA, giving some discretion to facilities as to how to run their programs.
3. The Three Rs
The Guide revolves around one of the key principles to animal testing – The Three Rs. (See p. 4-5 in The Guide). The Three Rs represent the three goals researchers must keep in mind when designing experiments, particularly when using animals: replacement, refinement, and reduction. Replacement means that any researcher should consider if there are alternate methods such as replacing animal subjects with animals lower on the phylogenetic scale or non-living alternates. Refinement indicates that a study must be designed with all reasonable measures to ensure that there is absolute minimization of pain and distress. Finally, reduction stresses that researchers should strive to minimize the number of animals needed in their study, whether by lowering the number of subjects to be used or by maximizing the amount of information to be learned from each animal. It should be noted that the Three Rs do not always take precedent over scientific inquiry. Some studies may inevitably result in chronic or severe pain in animals, but refinement indicates that researchers must provide appropriate justification if not a humane endpoint to euthanize the animal for their choice in such a study design. Reuse of animals without good reason is also not recommended for the well-being of the animal. Additionally, animal reuse may also have an effect on the accuracy of data.
Interestingly, the Guide also provides additional recommendations for social housing and environmental enrichment for animal housing. While the Guide strongly recommends that single housing of a social species should only be done as an exception, the Guide does not provide a definition for what constitutes a social species. (See p. 64 of The Guide). The Guide also recognizes that individual animals may simply sometimes be socially incompatible, leading to stress and injury if housed together. If individually housed, it is also recommended that environmental enrichment be provided, such as a toy, in order to ensure that the animal has mental and motor stimulation while housed. Since toys that may benefit one species may stress another, the IACUC should be responsible for reviewing the facility’s enrichment program and determining appropriate species-specific stimulation. (See p. 53 of The Guide).
The Guide for the Care and Use of Laboratory Animals is available at http://www.aaalac.org/resources/Guide_2011.pdf.
V. Animal Models
Non-human species frequently used in research are referred to as model organisms. Choice of species may often be dependent on the goal of a research study. Certain species are preferred for the similarity of their body systems to humans, making any knowledge or results from experimentation applicable to humans. Additionally, a researcher may consider using a smaller species if a large number of subjects are needed. Another concern could be whether a species’ temperament is well-suited to the study design as some species may be more active or skittish. The following are only some of the commonly used vertebrate species in testing today and their functions. (Note that this list does not include the invertebrate species that are also used in biomedical research.)
A. Mice and Rats
Mice and rats compromise an overwhelming majority of lab animals. Given the exclusion of mice and rats from AWA coverage, it is difficult to track the exact number of mice and rats used each year. The American Anti-Vivisection Society estimates that 95% of laboratory animals are mice and rats, making up to 100 million animals. (See http://aavs.org/animals-science/animals-used/mice-rats/#.VBb226R0zIU). One benefit of using mice and rats is their cost-efficiency. Both species take little space and can be housed in large groups on cage racks. Additionally, both can be easily bred, making them a relatively cheaper alternative than most other species. Given their short life-span, mice and rats are not usually recommended for long-term studies. Both of these species are also very prone to genetic mutations later in life, often developing tumors as they age due to an extended lifespan from living under care. Given these qualities, mice and rats are preferred for carcinogenic, aging, and genetic studies. The relatively short lifespan of a mouse or rat allows for a researcher to observe the development of cancer or the effects of aging over the entire lifespan of the subject. Mice and rats may also be bred to be genetically altered, allowing researchers to develop models with the genetic disorder or disease they are studying.
It is important to note that mice and rats are not covered under the AWA although there are some recommendations for rodents in the Guide despite their status as one of the most popular model organisms for biomedical research. The contrast between the popularity of rodent use in the laboratory compared to the extremely limited protection given to these species has been a large point of contention in the debate for laboratory animal protection. Most current protections for mice and rats are only available as voluntary standards although FDA regulations may establish a baseline standard of care.
Though slightly larger animals, rabbits are also popular as small and relatively nonexpensive animals. As a prey animal, rabbits are naturally inclined to a docile although skittish temperament, allowing for easy handling. (See Calasans-Maia MD, Monteiro ML, Áscoli FO, Granjeiro JM (2009). "The rabbit as an animal model for experimental surgery," Acta Cir Bras 24: 325–328, available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3283968/). Because of their powerful hind legs, extra care must be taken in learning how to handle them, as a panicked rabbit can easily break its spine with its kick if not held properly. Rabbits are particularly prone to stress and should be kept in a quiet environment separate from other animals, particularly predator animals.
Rabbits have gained fame as the iconic research animal due to their use as subjects for eye irritancy tests for the cosmetic industry. Although these tests have been in decline, rabbits are still used today for various other areas of research. Most notably, rabbits are used for antibody production. (See "Rabbits" at http://ori.hhs.gov/education/products/ncstate/rabbit.htm). Currently, there are no alternatives to producing antibodies outside of a living system although rabbits are not the only species to be used for this purpose. Harvested antibodies can be used to create probes to detect certain targeted molecules in later research. Other areas of study in which rabbits are used are for cancer, cardiovascular diseases, dermatology, ophthalmology, and osteology. (See "Rabbit" at http://www.animalresearch.info/en/listing/255/rabbit/).
Swine are an increasingly popular model organism due to their similar physiology to humans. Larger pig breeds tend to be more expensive and difficult to house given the amount of room needed to accommodate such large animals, lending to the popularity of minipig breeds as well.
Pigs are usually used for studies focusing on the cardiovascular, urinary, or digestive systems. Swine hearts tend to be much larger than other subject alternatives like the dog and, in some breeds, are analogous to the size of the human heart. Given the rapid growth of individual swine, the pig is ideal as a model for growing hearts although researchers should be aware how large some breeds of the animals may become over long-term studies. Swine kidneys are also more similar to human kidneys than those found in most other species. There are also several pig breeds that are especially prone to developing diabetes, making them excellent models for studies focusing on the disease. Additionally, swine skin is remarkably similar to that of humans, making them equally suited for skin studies such as wound or plastic surgical studies. (See "Swine as models in biomedical research and toxicology testing," Swindle MM, Makin A, Herron AJ, Clubb FJ Jr, Frazier KS. Vet Pathol. 2012 Jul;49(4):738, available at http://vet.sagepub.com/content/49/2/344.full).
D. Sheep, Goats, and Cows
Ruminants are another type of farm animal commonly used in research. It is important to note that ruminants are more complex in terms of sedation and anesthesia. Due to the configuration of the ruminant digestive system, ruminants are prone to regurgitating when sedated, particularly for long periods of time. (See "Small Ruminant Anesthesia," Sharon Kaiser-Klingler, RVT VTS, avaiable at https://www.acvs.org/files/proceedings/2012/data/papers/170.pdf). Care should be taken to assure that sedated ruminants do not aspirate any regurgitated fluids while under. Another concern is in bloating. As ruminants are constantly re-chewing and fermenting their food, gas buildup can often cause sedated animals to bloat severely if they are under for an extended period of time. For these reasons, ruminants are not particularly suited for long surgical procedures without a skilled anesthetist. Much like the rabbit, these ruminant species are known for a docile temperament, although they may still injure handlers if frightened by kicking with their sharp hooves. Separate long-term housing for social ruminants may also prove to be particularly stressful to individuals. (See "The Sheep" at http://www.adelaide.edu.au/ANZCCART/publications/A9_SheepFactSheet.pdf).
Ruminants are used for areas of research such as endocrinological, cardiovascular, and immunological studies.
E. Cats and Dogs
Cats are frequently used for neurological or viral studies. (See "Cats" at http://ori.hhs.gov/education/products/ncstate/cat.htm). Dogs are usually suited for cardiovascular, dental, and musculoskeletal studies. (See "Dogs" at http://ori.hhs.gov/education/products/ncstate/dog.htm). Both species can sometimes be more easily trained if needed than farm species. Despite constituting a very small portion of research animals, cats and dogs remain the most controversial laboratory animals due to their association as companion animals. For further discussion on sourcing of animals, see Section VI.
F. Non-Human Primates
Non-human primates are also a minority used in research. (See "Primates in Biomedical Research," published by the California Biomedical Research Association, available at http://ca-biomed.org/pdf/media-kit/fact-sheets/fs-primate.pdf). Humans and other primates are undoubtedly physiologically similar. Given their complex social and cognitive abilities, non-human primate testing also tends to elicit far more controversy than most other laboratory species. Coincidentally, the AWA also lists specific care requirements for the psychological care of primates due to their classification as higher species. (See § 2143b of the AWA and 9 CFR § 3.75 - § 3.92). Due to their similarity to human physiology, non-human primates are used as models for toxicology, neurological, and immunological studies. (See "Primates" at http://www.animalresearch.info/en/designing-research/261/primates/).
VI. Source of Testing Animals
The AWA makes it unlawful for any research facilities to purchase animals from anyone other than authorized operators of auction sales and licensed dealers or exhibitors (§2137). The USDA licenses animal dealers within the U.S. by class. The USDA breaks down licenses for animal dealers into two classes: Classes A and B. (For more, see "Licensing and Registration Under the Animal Welfare Act" at http://www.aphis.usda.gov/animal_welfare/downloads/aw/awlicreg.pdf).
A. AWA Licenses
Class A dealers breed and deal in animals that they themselves have bred and raised. Many of these dealers that serve research institutes are often specialized Class A dealers that breed animals specifically for the purpose of research. These animals are usually preferred for studies since they often have detailed health records since birth as well as any data about parental lineage. Due to these animals being bred for research, most variables that may affect the results of research can be significantly reduced by knowing the animal’s individual and inherited health history that is usually tracked by the breeder/dealer in their regular course of business.
In the context of animal research, Class B dealers are usually of more concern as purveyors of ‘random source animals’ (see below). It is important to note that not all Class B dealers sell to research institutions – Class B dealers are licensed dealers who may sell random source animals for research, exhibition, or as pets. This article only addresses Class B dealers to the extent of their relevance in the context of animal research. A list of Class B dealers can be obtained through a FOIA request or at http://www.aphis.usda.gov/animal_welfare/efoia/downloads/reports/B_cert_holders.pdf.
Class B dealers encompass brokers, bunchers, and operators of auction sales, allowing them to purchase and sell animals to research facilities as well. Animals procured from Class B dealers are often referred to as ‘random source’ animals due to their varying backgrounds. Animals from Class B dealers may have been purchased from individual breeders, shelters or pounds, or other licensed breeders. Additionally, animals purchased from Class B dealers are often more nonexpensive compared to those bred and raised by Class A dealers. Lack of control as to the sources of animals acquired by Class B dealers has recently led to concerns of lost or stolen companion animals, particularly dogs and cats, being sold into research institutes. The number of Class B dealers has declined significantly in recent years, with only nine licensed dealers selling to research facilities in the fiscal year of 2009. (See http://www.aphis.usda.gov/animal_welfare/inspections_type.shtml). The decline is likely both due to the lack of control over variables for random source animals as well as the lack of demand for cat and dog subjects. (For more, see Overview of U.S. Animal Welfare Act).
B. State Laws on Research Animals
Several states address the selling of impounded dogs and cats to research facilities within their laws. Tennessee bars the purchase of dogs or cats by research facilities except from licensed dealers, public pounds, humane society, or from a breeder of research animals. Use of cats or dogs in Michigan for scientific testing of drugs or medicines is banned in Michigan without a license issued by the commissioner of public health. As such sources of testing animals for research facilities may depend on the jurisdiction.
VII. Methods of Euthanasia
Euthanasia is a regular occurrence with scientific research, either at the endpoint of a study or in order to end. 9 C.F.R. § 2.31(d)(xi) notes that “methods of euthanasia must be in accordance with the definition of the term set forth in 9 C.F.R. § 1.1, unless a deviation is justified for scientific reasons, in writing by the investigator. The regulation also states that “…recommendations of the AVMA panel on euthanasia should be followed." 9 C.F.R. § 1.1 defines euthanasia as “the humane destruction of an animal accomplished by a method that produces rapid unconsciousness and subsequent death without evidence of pain or distress, or a method that utilizes anesthesia produced by an agent that causes painless loss of consciousness and subsequent death." Methods of euthanasia vary by animal for a combination of reasons for physiological differences, cost-efficiency, and regulatory compliance. State laws may also vary as to which methods of euthanasia on which species are permissible. (See https://www.avma.org/Advocacy/StateAndLocal/Documents/euthanasia_laws.pdf for more information).
As referred to in Title 9, the American Veterinary Medical Association (“AVMA”) provides several guidelines for animal euthanasia by species. The AVMA Guidelines fore the Euthanasia of Animals is available at https://www.avma.org/KB/Policies/Documents/euthanasia.pdf. Common methods of euthanasia are usually by injectables, inhalants, or physical means.
For the majority of larger species such as ruminants, swine, dogs, and cats, it is usually considered an acceptable method to deeply sedate the animal before administering a lethal drug or drug cocktail intravenously. Physical methods such as gunshot or penetrating captive bolts are also listed for each species, but many states vary as to whether these methods are permissible within their jurisdiction.
For laboratory rodents, injectables are listed as an acceptable method. AVMA guidelines recommend that rodents be euthanized away from the sight or smell of other rodents. Inhalants are also acceptable given that death is confirmed. Euthanasia of this method may sometimes be preferred for large populations, unfortunately sometimes for reasons of cost and time-efficiency. While considered an unacceptable method for larger species, placement in gas chambers without anesthetic is considered an acceptable method of euthanasia for rodents. Euthanasia by inhalants is often coupled with a physical method to ensure that the animal is truly deceased as some rodents are known to wake up. Physical methods are also used for rodent euthanasia – the most common being cervical dislocation and decapitation. Cervical dislocation is often used for mice or smaller rats and benefits from speed and no need for additional lab equipment or supplies. A flat edge is usually placed gently on the back of the animal’s neck before the technician tugs its tail quickly and firmly. The result if done correctly is usually rapid dislocation and immediate death. It is important that technicians be trained properly in using this method, as hesitation or poor technique can result in a botched dislocation, leaving the animal in pain and distress. Decapitation using specialized guillotines may also be used. With either physical method, it is the discretion of the individual facility whether to anesthetize prior to its use. Some studies may require tissues collected from the animals to be uncontaminated by chemical agents, hence the need for a physical method. For rodents younger than 7 days of age, indirect contact with cool surfaces is also sometimes used to induce gradual death by hypothermia. (See https://www.avma.org/KB/Policies/Documents/euthanasia.pdf).
Rabbits are especially difficult due to their tendency to hold their breath around unfamiliar or unpleasant odors. Injectables are usually the accepted route of administration for these animals. However, inhalants may be used under the recommendation that the animal first be under anesthesia or sedated in order to reduce stress. Cervical dislocation with rabbits may also be used, although special devices may be needed due to their large size. Penetrating captive bolts are also listed as an acceptable method with conditions. (See https://www.avma.org/KB/Policies/Documents/euthanasia.pdf).
It is important to note that while all of these methods are listed as acceptable, it is also up to the discretion of the individual research facility whether to take extra non-required steps in ensuring a death free of pain and distress for the animal, such as additional sedation or anesthetic before the suggested method of euthanasia. Similarly, although the AVMA may list a method such as gunshot as acceptable under conditions, this would not indicate whether it has widespread use as it only lists the method as an option.
VIII. Problems and Controversies
Animal testing often elicits a strong emotional response from the public. On one hand, the concept of voluntarily inflicting pain and even death on another living being is ethically abhorrent. On the other, scientific medical advances from testing and research have contributed to a higher standard of living for many lives. Additionally, the inherent distrust between the public and the scientific community has led to tension between both parties.
A. Alternative Models
Over the past several years, proponents for alternative models to animal models have increased with support from well-respected scientific institutions such as Johns Hopkins University. In some cases, advances in the technological fields have allowed for the eventual replacement of animals with non-living alternatives. However, animal use in the biomedical industry still remains the prevailing standard for most research. The reasoning for this approach is in the current knowledge available. Given the current status of the technology, the complex reactions found within an organism’s system is still too complex and unknown to accurately simulate. While non-living alternatives are possible for certain studies, animal models are still considered the only possible option currently available to accurately obtain results. The Guide’s principles in the Three Rs implore researchers to consider using the minimal number of lives possible as well as to consider alternative options before beginning a study. It is important to note that animal biomedical research remains, above all, an industry. Despite regulations and ethical concerns, there are still economic incentives that remain for some research facilities to act otherwise.
B. Coverage of Animals
As previously noted, much discretion is often given to the individual facility as to the details of its animal care and use program. Additionally, much of research that is funded commercially will fall outside of PHS Policy regulations, excluding any animal welfare protection for mice, rats, and birds which make up the majority of research animals. AWA’s regulations can also only be disregarded if reasonable scientific justification is given, In an ideal world, this would be sufficient protection for covered animals. However, scientific justification often can encompass a large variety of reasons. In a commercial environment, it is unfortunately sometimes too easy to give in to economic factors or temptations and find reasons to circumvent regulations. As can be seen with existing federal regulations, most animal welfare protection in research relies on facilities self-monitoring and self-reporting. Although this is enough for well-managed and honest facilities, it is important to remember that regulations exist most importantly to limit the activities of the worst offenders.
C. Animal Release
Several concerns exist in the release of laboratory animals. At times, research facilities may encounter issues with surplus animals, usually been purchased as back-up animals to studies that were never performed or cancelled. Without a purpose, extra animals serve to consume facility resources (e.g. food, medication, staff time) and housing space and may sometimes be euthanized for disposal. Depending on the facility, sometimes these animals are used to at least educate and train staff on basic surgical procedures before euthanasia.
One major concern with the release of these laboratory animals from the testing facility is the potential public backlash, particularly if the location of the facility is revealed. As such, most institutions are unwilling to make themselves publicly known, choosing instead to either euthanize or discreetly adopt out animals through employees. It is important to remember that the majority of animals in research consist of rats and mice, followed by farm animals. Of the small percentage of research animals that are adoptable, there is also the concern as to whether released animals would be suited to life outside the laboratory. Most laboratory animals are acquired through Class A dealers who breed the animals specifically for research. As a result, many of the animals have been raised within a laboratory environment from birth, leading for the need for some to adapt to outside conditions. For some animals, this may mean adapting to noisier surroundings, learning to socialize with other animals, or how to tackle new problems such as stairs or drinking from a bowl rather than an automated fountain. Dependent on the breeding facility, this could also mean the animal was raised with a smaller degree of human socialization and may have already developed several behavioral issues.
Several facilities do have adoption programs to dispose unused animals, allowing them to conserve their economic resources while also avoiding additional deaths. However, like many aspects of an animal care and use program, this is largely dependent on the individual facility. Currently, there are few if any incentives for facilities to release unused suitable animals for adoption and a high risk in doing so, as discussed above. Although re-homing laboratory animals is a large risk endeavor for research institutions, there are few if any explicit regulatory prohibitions on the release of companion animals. As with most research institutions, the organization’s IACUC would usually be the starting point to implement an in-house adoption program. For more information, see https://awionline.org/awi-quarterly/2010-spring/adoption-can-be-option-animals-after-their-use-research.
As discussed, most regulations on animal testing are either based on a self-reporting scheme or through voluntary standards adopted by individual research facilities. For most institutions, preservation of a lifelong relationship with the USDA or FDA for as long as they remain within the industry is enough incentive to comply. While this regulation may be enough for respectable institutions, current legal protections for research animals leave much to be desired if only to curb the activities of the worst offenders. When compliance is based on trust between regulatory bodies and facilities, one must examine the economic incentives that may drive research institutions to act one way or another. It is important to remember that medical research, at least within the United States, remains, first and foremost, a business. Many of the current guidelines, including the Three Rs, indicate at least a desire for researchers to proceed in a direction that could eventually reduce the number of animals used if not use alternative means entirely (or at least animals that are considered to be lower on the phylogenetic scale). However, apart from ethical concerns, there appear to be few actual economic incentives for facilities to do so.
Public debate has also been lacking in the discussion for laboratory animal protections. Given the strong emotional response from the public at the mention of animal use in testing, research facilities are given no incentive to openly go about their activities at the risk of backlash. The tension between both the scientific community and the public at large has also led to differing opinions as to what is the realistically and economically feasible approach to the reduction of animals used in research as well as the necessity of certain procedures while may inflict pain or distress on an animal. As such, the world of biomedical animal research still remains largely behind closed doors, veiled from public review.