Human concerns with diseases that affect animals can be traced back form the earliest documented dates of the earliest human interactions with animals, which is manifested in the early understandings of magic and religions. Diseases affecting animals are still a concern mainly because of the resulting economic losses that they cause as well as the likely role that they play with respect to transmitting diseases to humans. This concerns led to the establishment of the veterinary medicine, which is concerned with studying, preventing, and treating diseases found in domesticated, wild, and animals utilized for scientific research purposes. Preventing, controlling, and eradicating diseases among animals are of economic importance are mainly agricultural concerns. On the other hand, preventing and controlling diseases that can be transmitted from animals to humans (zoonoses), particularly the diseases in pets and wild animals, is primarily a human health concern. Moreover, diseases affecting animals are increasing their importance, especially with respect to the impact they have on reducing the supply of animal-protein for humans. As a matter of fact, the World Health Organization (WHO) and the United Nations Food and Agricultural Organization (FAO) have initiated efforts aimed at solving the problem associated with the deficits of proteins amidst the significant increase in the population of the world. This paper performs a critical analysis of the statement “nonhuman animals are increasingly a source of disease of diseases that endanger people.” The paper argues that although diseases in non-human animals endanger people, they also contribute to an increased understanding of human diseases.
The first danger to humans posed by diseases affecting animals related to the negative impact they have on the supply of animal-protein for humans. The prevalence of chronic hunger and manipulation globally is about 50%. Moreover, insufficient diet is attributed to the deaths of thousands of people on a daily basis. In the 1980s, the world population was about 4.6 billion, and the time, food safety was still a concern. Presently, the population of the world is 7 billion, which is an indication of the need to increase the animal-food supplies. Increasing the animal-food supplies can be achieved by devising ways of controlling the diseases affecting animals globally, and particularly among the developing countries in Africa and Asia that are experiencing the most rapid increases in population. The bulk of the information relating to animal studies, nonetheless, relates to domesticated animals like sheep, cattle, and pig, which are considered relatively insignificant sources of food in these countries. Surprisingly, there is scanty information regarding the diseases affecting the alpacas, llama, yaks, elephants, camels, water buffalos, and goats – all of which are domesticated animals that are significant sources of animal foods in developing nations. Developing methods to help in controlling and eradicating diseases affecting non-human animals are urgently required in these developing nations. An estimated 33 percent of the urban poor and the 75 percent of the rural poor are dependent on livestock as the sources of manure, income, and food. Therefore, the losing a single milking animal, for instance, can have devastating impacts on these households, and in extreme situations, can lead to the deaths because of diseases that affect non-human animals. Generally, diseases affecting non-human animals are exacerbating the prevalent problem of chronic hunger and malnutrition across the world; hence, endangering people.
Besides worsening the already existing problem of hunger and malnutrition, diseases in non-human animals have resulted in heightened public concerns regarding the safety of foods. This has resulted in consumers perceiving food-producing animals as a risk that tends to dent their confidence in foods that are derived from non-human animals even when the risks on human health is non-existent or insignificant. Examples include the Avian Influenza crisis in Asia, the Foot and Mouth Disease and the Bovine Spongiform Encephalopathy crises in Europe. Developed countries have tried to minimize the risks posed by foodborne pathogens through the implementation of stricter animal control measures. For instance, food cannot be produced from diseased animals. Also, animals are inspected to determine whether they have infections before being slaughtered. An inference that can be derived from this observation is that diseases affecting animals pose a threat to the safety of food supplies, which in turn endangers people. Globally, the burdens posed by diseases in non-human animals have been found to be highest in India, Nigeria, and Ethiopia – all of which have the largest number of malnourished populations and poor people rearing livestock.
Although numerous effective methods have been developed to control the spread of diseases in non-human animals, considerable amounts of milk and meat supplies are lost annually across the world. In nations lacking sufficient animal-disease control measures, it is estimated that 30-40% of protein is lost due to diseases in non-human animals. Moreover, poor animal husbandry practices are also contributing to these losses. It can be seen that losses in animal-food supply remain a significant threat despite the establishment of effective animal-disease control measures.
For a long time, animals have been acknowledged to play a role in causing human disease. For as long mankind has existed on earth, humans have been jabbed, kicked, stung, or bitten by animals. Additionally, early man succumbed to illness and death through consuming flesh obtained from dead animals. Recently, it has been established that numerous invertebrate animals have the capability of transmitting causative disease agents from human to human as well as from non-human animals to humans. In this respect, animals act as carriers, agents, and hosts of disease; thus, are crucial in causing and spreading human disease. Since about 75 percent of known animal diseases are relate domesticated animals such as pets, the risk increases. Nevertheless, diseases in wild animals have also been found to facilitate the spread of human disease. Zoonoses denote the naturally occurring diseases manifested in both human and non-human animals. The transmission of such diseases like the bird flu, occurs between humans and non-human animals, and have detrimental impacts on the health of both humans and non-human animals. Researchers have reported that 13 of the diseases that affect animals account for an estimated 2.2 deaths among humans each year. Moreover, it is reported that the bulk of these deaths and illnesses are documented in middle-income and low-income countries, with Nigeria and Ethiopia in Africa, and India having the highest number of deaths.
A range of zoonoses ranging from avian flu to the tapeworms that cause cyst present a significant risk to the health of humans. Therefore, it is imperative to target the countries that have been hardest hit by diseases that affect non-human animals in order to protect global health and reduce the extreme poverty and illness levels among the poor livestock keepers of the world, who are about 1 billion. Furthermore, it has been estimated that an estimated 60% of all diseases that affect humans and 75% of emerging infectious illnesses are attributed to diseases in non-human animals. The majority of diseases that affect humans derived from animal diseases come from livestock such as camels, sheep, goats, cattle, and pigs. Zoonoses have severe impacts with respect to human deaths, human disease, and livestock disease and deaths. Some of these zoonoses that have a considerable role in human disease include anthrax, hepatitis E, zoonotic sleeping sickness, brucellosis, zoonotic tuberculosis, leishmaniasis, rabies, cysticercosis, leptospirosis, and zoonotic gastrointestinal disease among others. In sum, it can be been seen that animals are a source of disease have a potential danger on humans.
Whereas diseases affecting animals endanger humans through their roles in causing and transmitting human disease and reducing the supply of animal protein, they are also beneficial in the sense that they contribute towards understanding human disease. There is no doubt that the role played by domesticated animals in causing diseases that can be transmitted between animals and humans is well understood, the role played by diverse wild animals that have less association with humans in causing zoonoses is not understood well. It is worth noting that the discovery of diseases like plague, viral infections of the brain and yellow fever and other diseases that affect humans and domesticated animals are essentially diseases that originated from wild animals and exist independently. However, these discoveries have heightened the interest and significance of exploring wildlife diseases.
Despite veterinary and human medicine are separate medicine fields, veterinary observations have been found to contribute to the medical knowledge, especially that which is pertinent to human beings. Only a few species of animals, out of at least 1.2 million that been discovered have been used in research despite the possibility that, for each known human disease, there is a similar disease that affects animal specifies. The important role played by veterinary medicine in human health is increasing in significance because of the utilization as animals that serve as biomedical models that have the same disease as that affecting humans. The usage of animals as biomedical models is significant since the research focusing on the majority of chronic and genetic animals cannot be performed with human subjects.
Hundreds of thousands of animals such as monkeys and mice are utilized in research labs in the United States alone. Through animal studies, novel surgical techniques have been developed. Moreover, animal studies have been helpful to test the safety of drugs. Additionally, they have been helpful in conducting nutritional research. Using animals have also provided important insights that have helped to understand chronic degenerative illnesses since these diseases can be introduced in animals through experimentation and then studied. The significance of chronic degenerative illnesses like cardiovascular diseases and cancer has grown in tandem with the increase in the number of infectious diseases that have been controlled effectively. Some of the diseases found in animals that are similar to those occur in humans are the chronic emphysema that affects the horse; gastric ulcers that affect swine; urinary stones affecting cattle and dogs; cataracts that affects the eyes of mice and dogs; hydrocephalus and ski allergies affecting numerous animal species; blood coagulation affecting dogs; and hereditary deafness affecting numerous small animals, and so on. Therefore, studying animals with diseases that are same as those that affect humans has been instrumental in increase the body of knowledge relating to human diseases and nutritional knowledge. Animal studies have also been extensively used in the development of surgical techniques for organ transplantations, testing of novel medications, and techniques for open-heart surgery and shock.
It is evident that non-human animals are a prominent source of diseases affecting people. Diseases that affect animals have detrimental impacts on the supply of animal food; hence, exacerbating the problem of hunger and malnutrition globally. Also, zoonotic diseases have also reduced the confidence that people have in food derived from animals. Zoonotic diseases also play a crucial role in causing and transmitting diseases since animals act as carriers, hosts, and causative agents of disease. Despite these threats to human health, studies on non-human animals are providing important insights that enhance the understanding of human disease. On the whole, when diseases in animals are effectively controlled coupled with extensive animal studies, animal studies can be beneficial to humans.