2015

Eva Quintero

IDS 4934-001 (25590)

April 8, 2015

Contributions of Animal Research to Public Health: A Look in the Past and into the Future

Introduction

For centuries animals have been used for biological research and expanded our

knowledge of medicine and public health. This paper will focus on the history, ethics, and

scientific developments associated with animal research specifically in relation to the public

health system. This paper will also contain information regarding new technological

advancements and improvements in the field of animal research.

There are many ethical and real world issues associated with animal experimentation.

However, even with today’s advances in technology, animals continue to be used for the

development of new life-saving drugs and medical procedures. Animals share many

physiological and genetic similarities with humans, making them ideal models for biological

studies. Throughout history, animal research has contributed to the maintenance and promotion

of public health. Therefore, the use of animals in a responsible and ethical manner for

biomedical research is needed in order to make further advances in human health. Animal

testing is a necessary means for advances in scientific knowledge particularly regarding the

surveillance and prevention of disease in public health.

History of Animal Research

I. Animal research is hardly a new concept and has a surprisingly long history. Aristotle is

believed to be one of the first known to have performed experiments on living animals (Hajar,

2011). Likewise, a Roman physician named Galen dissected goats and pigs to learn of their

anatomy and physiology, a practice which later earned him the title “the father of vivisection”

(Lloyd, 2008). The first observations of great importance to modern science were made in the

1600s, when William Harvey used animals to describe the blood circulatory system (Lloyd

2008). These are only a few examples of how animals have allowed us to better understand the

mechanisms of the human body.

Ethics

II. Despite this, there is an ongoing debate about the ethics of animal experimentation. Many

people feel that it is wrong or selfish to treat animals as tools in order to gain scientific

knowledge. On the contrary, others believe that the benefits that arise out of experimentation

outweigh any harm done to the animal. There are some who consider health as an “asset shared

by all species, animal and human, that would be guaranteed by a single medicine guided by

biomedical research” (DuCrot, 2011). In other words, both animals and humans share the overall

benefits that arise from animal experimentation.

Throughout its history, the practice of using animals for biomedical research has come

under severe criticism by society and more recently by animal rights groups and animal activists.

Those who oppose animal research would agree that animals have a moral status equal to that of

humans and therefore feel that it is wrong to needlessly hurt other animals. In the 17th century,

English philosopher John Locke fully recognized that animals were capable of feeling pain and

certain emotions and stated that “children should be brought up to abhor the killing or torturing

of any living thing in order to prevent them from later becoming capable of cruel actions to

fellow humans” (Franco, 2013).

There are many modern day organizations that strongly oppose the animal research

including People for the Ethical Treatment of Animal (PETA) and the Animal Liberation Front

(ALF). These organizations focus their attentions on protecting animals from cruelty and abuse,

removing the status of animals as property, and ending animal testing. Many times, animal rights

activists have carried out raids to release animals from laboratories and farms. There are

documented cases where organizations such as the Oxford Arson Squad have participated in acts

of physical violence, arson, and property damage to animal research facilities (Animal extremists

'more violent', 2005). The humane treatment of research animals is certainly a legitimate point;

however, total elimination of animal testing would significantly withhold the discovery of new

medicines, treatments, and other scientific developments.

In today’s society, the concept and understanding of animal health research is changing,

along with the perception of scientists' personalities. In the 1950’s scientists were regarded in

high esteem even though they were not completely understood. In recent times, however,

scientists are often stereotyped as remote, withdrawn, secretive, and unpopular. There is a

common misconception that scientists deliberately inflict harm, pain, distress, or death on

laboratory animals. Andrew Rowan puts it well when he states “There is a constant tug of war in

the public mind between perceptions of the scientist as hero and as villain” (1995). In other

words, scientists are both admired for their contributions to public health but criticized for their

methods involving animal use.

Animal Welfare Regulations

III. According to Rachel Hajar, “issues such as ‘cruelty’ to animals and the humane

treatment of animals are valid concerns, and hence, the use of animals in experimentation is

greatly regulated” (2011). These regulations include but are not limited to pain management and

the use of anesthesia for animal subjects, providing appropriate living conditions, and requiring

proper training to those who handle the animals.

Those in favor of animal experimentation would argue that there are many principles and

regulations involved with animal research that research institutions and organizations must

adhere to which are designed to ensure the best possible treatment of the animals used in a study.

For instance, there are many studies that focus on behavior, genetics, diet and exercise among

others that do not cause pain or suffering to the subject. Another principle involves the use of

less complex organisms whenever possible such as fish, birds, and fruit flies. The use of these

organisms would be preferred over mammals in regards to a moral standing, although sometimes

the use of mammals is necessary to the study and cannot be avoided. It is important for society to

understand that laboratory animal facilities are regulated by government agencies and require

researchers to provide justification for using animals.

One of the biggest changes to animal research was the integration of the 3 “R’s, which

serve as guiding principles for the ethics of animal experimentation. The three R’s encourage

individuals to 1) replace animals with non-living models when possible (2) reduce the number of

animals used to obtain sufficient data to answer the research question; and (3) refine animal use

practices to minimize pain and distress, and to enhance the welfare of an animal used (Hajar,

2011). These guidelines have helped buffer some of the negative attitudes of those who feel

uncomfortable with animal experimentation by advocating humane experimental techniques.

By employing the 3Rs when continuing to use animals for scientific research, the scientific

community can affirm its moral conscience as well as uphold its obligation to society to further

the advancement of science for civilization and our public health system.

With a better understanding of the methodologies involved in animal research it is

important to recognize the significant impact that animals have made in public health and

modern medicine. Some of the major influences of animal experimentation on public health

include the development of vaccines, life-saving drugs and treatments, and data regarding

diseases of the past as well as current medical conditions. The development and production of

vaccines and antitoxins led to a dramatic increase in the number of animals used in biomedical

research (Franco, 2013).

Contributions of Animal Research to Public Health

IV. The use of animal models has led to the creation of vaccines for diseases like polio,

measles, whooping cough, and others. By the early twentieth century, bacterial diseases had been

studied extensively and the use of antibiotics was beginning to take effect. Viral diseases,

however, were not as well understood. During the 1950s, decades of laboratory research on the

polio virus had improved scientists’ ability to study it and to cultivate it in animals. Without

proper treatment, prevention consisted mostly of advice to avoid beaches, swimming pools, and

crowds during the summer season.

According to the CDC, polio crippled around 35,000 people each year from 1940 to 1950

in the United States alone, making it one of the most feared diseases of the era (Polio, n.d). By

injecting cultured fluid from the polio virus into mice and monkeys, scientists were able to

reproduce paralysis typical of polio in the subjects and ultimately developed a vaccine used to

treat the disease (Hansen, 2009). Without the use of animal models, the virus may have

continued to spread and crippled thousands more people. Franco states that “by the end of the

nineteenth and beginning of the twentieth century, the pharmacopeia had effective, scientifically

tested drugs, a landmark that allowed for an increasing number of people to understand the

importance and validity of scientifically sound medical knowledge and, with it, the relevance of

animal-based research” (2013).

Another important topic of concern regarding animal research involves diseases that can

be transmitted from animals to humans. These diseases are referred to as zoonotic, and have

impacted society throughout history and continue to cause problems. Animals are seen

throughout our public health system. Apart from serving as research models, they also represent

sources of food as well as forming a part of our daily lives as companion animals. These

relationships with animals expose us to a number of animal diseases that can be acquired by

humans including rabies, brucellosis, leishmaniasis and echinococcosis. These diseases continue

to occur in many countries causing the deaths of millions of people every year.

Studies show that animals may also be healthy carriers of agents that are pathogenic for

humans but which do not affect the health of the animal (for example, Salmonella and

Campylobacter) (Ducrot, 2011). Regarding zoonotic diseases, animal research provides a

mutually beneficial outcome for both animals and humans by eliminating the disease in both

groups.

One of the most noteworthy cases of animal research involving zoonotic diseases was

that of Louis Pasteur and his influential work on immunology, specifically for the rabies virus.

Louis Pasteur was a French chemist and microbiologist who hypothesized that microorganisms

could be the causative agents of many diseases that affected humans and other animals (Franco,

2013). His study of microorganisms allowed him to develop the “pasteurization” method which

would destroy bacteria found in food that would cause it to spoil. Furthermore, he was able to

identify several types of zoonotic diseases including Staphylococcus, Streptococcus,

Clostridium, as well as the causative agents of anthrax (Franco, 2013).

Rabies in particular was a concerning disease for both animals and humans in the 19th

century. The virus itself causes acute inflammation of the brain and when left untreated leads to

violent movements, a distinct fear of water, an inability to move parts of the body, confusion,

and loss of consciousness (Rabies, 2013). After symptoms appear, rabies almost always results in

death.

In his experiments, Pasteur infected rabbits and dogs with the rabies virus in his attempts

to find a cure. The public heavily slated Pasteur’s use of animals, particularly dogs. It was

known, however, that Pasteur was perceptive to animal suffering and used several techniques to

limit the animals’ pain or distress. He made sure that animals were anesthetized whenever

possible to prevent unnecessary suffering and he even use what we now call “humane endpoints”

or euthanasia if he thought the animal was experiencing too much discomfort (Franco, 2013). In

the end, Pasteur was able to create the first vaccine for rabies, one of his many direct

contributions to public health using animal research. The vaccine was also a major development

for veterinary medicine as it saved countless animals from acquiring rabies and enduring the

horrific symptoms.

Similarities Between Animal Models and Humans

V. Yet another reason why animal use is so crucial to our understanding of medicine and

disease is because of their genetic and physiologic resemblance to humans. Many animals,

specifically mammals, share many anatomical and genetic similarities with humans, making

them good models for biological studies. In today’s animal research facilities, rodents such as

mice and rats have been the primary models for studying specific aspects of human pathogenesis

and immunity (Lanzas, 2010). In fact, rodents are the most commonly used laboratory animals,

making up nearly 80% of the total of animals used in the European Union, followed by cold-

blooded animals (fish, amphibians and reptiles, making up a total of 9.6%) and birds (6.3%)

(Franco, 2013).

Historically, Nuno Franco states that “the toning down of the opposition to animal use in

the life sciences had also something to do with the emergence of rodent species as a recurrent

animal model in research” (2013). Seen as sources of disease and considered pests, rodents like

mice and rats were despised by the public and therefore made them less worthy of moral

consideration. Scientists took this as an opportunity to use this to their advantage and began to

adopt them as their research models. As it turns out, rodents make excellent research models not

only for their anatomical and physiological similarities but also for their inexpensive housing

costs and care. For genetic studies, rodents reproduce easily and scientists are able to quickly

obtain results over a short period of time.

“In 2002, the mouse became the second mammal, after humans, to have its whole

genome sequenced” (Franco, 2013). Studies have shown that 75% of mouse genes have

equivalents in humans, making them an essential model for human medicine (2002 Release: The

Mouse Genome And The Measure of Man, 2012). Knowing that mice carry virtually the same

sets of genes as humans allows scientists to experimentally test and learn more about the

function of human genes, ultimately leading to better understanding of human disease and the

development of treatments and cures. The improvements in the genome research project, along

with other technologies, have opened unlimited possibilities for the understanding of gene

function and their influence in several genetic and non-genetic diseases.

While rodents are making a significant impact in the laboratory, farm animals are serving

as natural models for a wide range of human infectious diseases at the veterinary and agricultural

level. Veterinary public health is focusing on using farm animals to better understand pathogens

that are shared by both livestock and humans. According to a recent study, more than half of

human infectious diseases are caused by multi-host pathogens for which farm animals are often

natural hosts and serve as infection reservoirs for humans (Lanzas, 2010). The use of farm

animals is becoming increasingly popular for studying infectious disease dynamics at the

population level.

Human health is inextricably linked to animal health and production. Farm animals make

up a substantial part of our diet, therefore it is critical to maintain their health and continue to

promote the importance of food safety in public health. For instance, veterinary public health is a

branch of the World Health Organization that focuses on the diagnosis, surveillance,

epidemiology, control, prevention and elimination of zoonotic diseases (Veterinary public health,

n.d.). In doing this, it is incorporating animal research into farm animals and agriculture.

Veterinary public health is also directly involved with the management of health aspects of

laboratory animal facilities and diagnostic laboratories to ensure the wellbeing of animals being

used for biomedical research.

Medical Advancements and Animal Research

VI. Every day, animal research is reaching new heights and expanding our knowledge of

modern medicine. Some of the newer developments in animal research include the new

production of biological products and medical devices as well development of life-saving drugs

such as cancer-fighting agents. Animals have even been used as models in clinical trials for

successful organ transplantation.

Modern technology has brought about a vast amount of new and beneficial devices,

particularly in the field of medicine. Devices such as surgical robotics are being seen in operating

rooms more and more frequently. M. Michael Swindle defines robotic surgery as the “use of a

remote console by a surgeon distant from the patient allowing the user to operate by means of a

virtual three-dimensional procedure” (2007). Robotic surgery with the da Vinci Surgical System

was approved by the Food and Drug Administration in 2000 (Robotic Surgery, n.d). The

technique has been rapidly adopted by hospitals in the United States and other parts of the world

for use in the treatment of a wide range of conditions. Robotic surgery has revolutionized the

idea of minimally invasive surgery and has proven to be very useful for common procedures

such as hysterectomies, cholecystectomies, nephrectomies, prostatectomies, among others.

Swine are routinely used as models for robotic surgeries for several reasons. Swine share

many anatomical similarities to humans which make them ideal models for robotic surgical

procedures, which require training both using in vitro and in vivo models (Swindle, 2007). Pigs

have all of the same thoracic and abdominal organs as humans with only minor differences in a

few organs. The most common areas of interests include the cardiovascular, urinary,

integumentary, and digestive systems. Retroperitoneal fat is almost absent in the pig which

facilitates laparoscopic procedures in the abdominal cavity as well allowing medical students and

doctors to enhance their techniques on an animal model before transitioning to a clinical setting

(Ruurda 2003). . Some of the benefits of minimally invasive surgery include: fewer

complications, such as surgical site infection, less pain and blood loss, quicker recovery, and

smaller, less noticeable scars. Technology of this kind is expected to continue to evolve and

improve with the help and use of animal models.

Swine have also effectively served to provide a better understanding of the cardiovascular

system. According to the literature, “the size of the heart and blood vessels in sexually mature

Hanford minipigs is more analogous to the size in humans than is either the dog or the nonhuman

primate” (Swindle, 2012). In fact, studies found that the blood supply to the coronary arteries and

the blood circulatory system of pigs is similar to 90% of the human population making them

ideal candidates for cardiovascular system studies (Swindle 2012).

The use of swine in the biomedical research has created a profound effect in both the

surgical environment as well providing further insight on the anatomical structures and functions

of the human body. Michael Swindle respectfully acknowledges the use of swine in the

laboratory when he states that “a brief review can only scratch the surface of the potential for

swine research models, but it illustrates the versatility of the pig and the wide variety of studies

in which pigs can be used” (2012).

Without a doubt, the use of animals in biological research has changed the history of

human medicine. The study of animals of all different species has made it possible to overcome

disease and created the foundations for a better public health system. The question remains, how

long will animal research continue to be necessary for the benefits of science and modern

medicine and when will it be deemed appropriate to discontinue the use of animal models?

Controversy Regarding Retired Animal Research Models

VII. A recent article discusses the controversy of the retirement of hundreds of non-human

primates that are being held for potential medical experimentation. According to the article, the

National Institutes of Health is responsible for hundreds of chimpanzees distributed throughout

several government research facilities, many of whom are aging and have been intentionally

infected with HIV or hepatitis (Bonifield, 2015). Although a few of the chimps have been

relocated to sanctuaries for retirement, more than 300 of them remain at the research facilities

and several have already died waiting on approval for their release.

It is unfortunate for these chimpanzees to be kept in laboratory confinement especially

since the NIH has admitted that scientific advances have rendered the use of non-human primates

largely unnecessary for research (Bonifield, 2015). However, due to the health complications of

the animals, the release of the chimpanzees is a complicated process. The majority of the chimps

have been infected with HIV or hepatitis. These diseases require daily treatments or medications

that could not be easily administered at the sanctuaries.

The unusual circumstances of these chimpanzees creates a dilemma associated with the

long term effects of research studies and brings up the ethical problems regarding the quality of

life of the animals. These are the challenges that society faces concerning animal models for

research and many times it is uncertain what should be the best approach to these types of

situations. Ultimately, scientists should make every effort to obtain the most relevant data and

information from these animals and attempt to use alternative and more efficient models for

upcoming projects.

Conclusion

Overall, there is an overwhelming amount of evidence illustrating how animal models

have impacted our public health system and contributed to our understanding of modern

medicine. The purpose of this paper was to illustrate the necessity of animal research for medical

advancements and improvements in our public health system as well discuss the history, ethics,

and numerous contributions animal models have made to biomedical science.

With each century came new changes and developments that improved both the lives of

humans and animals. From discovering life-saving vaccines that helped eradicate disease to

improving surgical skills of today’s doctors, animals have undoubtedly impacted the scientific

community. Still, animal research remains a controversial matter. It is crucial to acknowledge

that when used appropriately, animal medicine can save both the lives of humans and other

animals. Moreover, government agencies have made strenuous efforts to ensure that animal

models used in biological research receive the best treatment and quality of life. New regulations

and principles regarding animal experimentation have allowed society to be more accepting of it

and encouraged researchers to refine their studies so that they can obtain the most data from each

experiment. If used in an appropriate and responsible manner, animals used in biomedical

research can continue to serve as a leading scientific means of medical advancement and remain

an ongoing source of improvement to our public health system.

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