World Veterinary Day 2020
Environmental protection for improving animal and human health

Dr K Rashbehari Singh *

World Veterinary Day (WVD) 2020 will be celebrated globally on the 25th April 2020 on the theme of, 'Environmental protection for improving animal and human health' and it is an opportunity to highlight the contributions of veterinarians to the health of animals, society and the environment.

Environmental Health

Environment is the complex of physical, chemical, and biotic factors (such as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determine its form and survival.

On the other hand, environmental health is the branch of public health concerned with all the aspects of the natural and built environment affecting human health. Environmental science, environmental and occupational medicine, toxicology and epidemiology are the major sub disciplines of environmental health.

Together For One Health

One Health is the idea that health of the people is connected to the health of animals and our shared environment. We can achieve the best health for everyone by working together. The One Health Commission, the One Health Platform, and the One Health Initiative Team initiated International One Health Day in 2016 and the day was celebrated around the world every year on November 3.

Zoonotic diseases (infectious diseases caused by bacteria, viruses, or parasites that spread from animals, usually vertebrates to humans), can be spread between animals and people. Animals can spread more than half of all infections people can get e.g. rabies, Salmonella, and West Nile virus.

Environmental issues such as harmful algal blooms or lead contamination also can affect the health of both animals and people. Another emerging threat to the health of people and animals is antimicrobial resistance, and resistant germs often spread through our shared environment.

Our relationship with animals and the environment changes as the population of the earth grows. People live closer together, travel more often around the globe, alter the environment, and have different relationships with animals for companionship, food, and more. It is easier for diseases to spread between animals and people with all of these changes.

Animals sometimes give early warning signals of potential human outbreaks. Proper tracking of diseases in animals helps to keep the domestic and wild animals healthy, and this in turn helps to prevent illnesses and disease outbreaks in people.

Everyone, from pet owners, travellers, and farmers to anyone who buys and eats food or drinks or swims in water will be affected by One Health issues. In order to improve the health of people, animals, including pets, livestock, wildlife and the environment for One Health approach, it is essential for the experts to work together.

Disease experts, laboratorians, human healthcare providers, veterinarians, physicians, nurses, scientists, ecologists, and policy makers are involved in One Health work. Working together allows us to have the biggest impact on improving health for both people and animals. All of this work can help to predict, prevent, and control zoonotic disease outbreaks that threaten human and animal health, and can address other threats that affect humans, animals, and our shared environment.

A concept document was coauthored in 2010 by the World Health Organization (WHO), the Organization for Animal Health (OIE), and the United Nations Food and Agriculture Organization (FAO) , stressing the need for the three global human and animal health organizations to cooperate in a One Health model to address zoonotic diseases and other health risks at the human-animal-ecosystem interface.

Cooperation and collaboration among human, animal, and environmental health professionals appear likely to change the landscape of public health and clinical practice related to the prevention and control of zoonotic diseases and the recognition of animals as sentinels of environmental health hazards.

The present global outbreak of COVID-19 which is originated from Wuhan, Hubei Province of China is a glaring example for the need of One Health approach while managing animal and human diseases and our shared environment.

Human, Animal, And Environmental Health

Demographic changes in human and animal populations

Increasing human population of the earth impacts not only our health, but that of food and companion animals and of our environment. Increased meat consumption, globalization of the food supply, and migration of humans and animals all play a pivotal role in how we address current and future challenges.

Human and food animal populations

The parallel increase in global human and food animal populations and their effects on wildlife and ecosystem health are creating such unprecedented linkages between global human health and animal health.

Insufficient availability of grazing land, the need for greater, more efficient livestock production, and a desire for increased biosecurity results in rapid transition toward concentrated animal-feeding operations and other intensive forms of livestock farming.

Movement of humans and animals

There is an unprecedented global movement of animals because of worldwide trade in wild and exotic pets, some of which are illegal. This movement carries a risk of infectious-disease importation. Current mechanisms for quarantine and inspection for checking the diseases may not be adequate to prevent future novel introductions of disease.

Humans who have contact with animals in a remote area of a developing country can board a plane and travel to an industrialized country the following day, because of the ease of global travel. Thus, zoonotic diseases have greater potential than ever before to initiate global outbreaks in humans.

Animal workers

More than one billion people worldwide who work on a daily basis with food animals or their products, which include farmers, abattoir workers, and market workers, are at particularly high risk. Risks to such workers include injury, allergic exposures, exposures to organic dusts, and chemicals from confinement operations as well as infection such as zoonotic influenza, Methicillin- resistant Staphylococcus aureus (MRSA), brucellosis, Rift Valley Fever, and Escherichia coli.

These workers are less organized compared with industrial workers and they do not have access to preventive occupational safety and health programs or personal protective equipment when they perform tasks that may involve intense exposures to blood and body fluids and other animal materials. In addition to this, animal workers can be the bridge between zoonotic pathogens and the general human population.

For example, wives of swine workers have demonstrated elevated rates of seropositivity to swine influenza viruses. The lack of protection these workers receive during handling of animals may therefore have global public health consequences.

Health of companion animals

With the rise of human populations, there is also swelling of the world's population of companion animals, indicating the strength of the human-animal bond. There are positive health effects from such attachments, including improvements in physical and mental well-being.

With the increase of the global population of companion animals, there is increase global demand for pet food, which constitutes another market for animal products, which is associated with risks to both animals and humans of infection with Salmonella spp. and other pathogens.

Considering the importance of companion animals in our life, it is required to create better guidelines for interaction between human and animal health professionals regarding companion animal issues.

Developing and testing pilot mechanisms of collaboration between veterinarians and human health care providers and defining the role of the veterinarian in the human health care team are required. Updating medical school curricula to introduce interprofessional communication and collaboration is also required.

Environmental health and hazards

To sustain life, all organisms depend on their environments for energy and materials needed such as clean air, potable water, nutritious food, and safe places to live. More than medical technology, advances in agriculture, sanitation, water treatment, and hygiene have had a far greater impact on human health.

Lack of basic necessities of life is a significant cause of human mortality. The risk of cancer, heart disease, asthma, and many other illnesses increases by environmental hazards, which can be physical, such as pollution, toxic chemicals, and food contaminants, or social, such as dangerous work, poor housing conditions, urban sprawl, and poverty.

There may be adverse environmental effects because of the activities that promote health and extend human life. Use of pesticides and fertilizers, soil salinization, waste produced by livestock, carbon emissions from food manufacturing and transportation, deforestation etc. damage the environment.

Overpopulation resulted from reduction in mortality from starvation or disease, stresses the environment in many different ways by increasing use of fossil fuels, clearing of land, generating pollution and waste, and so on.

Emergence and management of zoonotic diseases

Many infectious diseases have emerged in recent decades with often devastating consequences for global health and impacts on trade and economies. Examples are SARS, Nipah virus, avian influenza, and MRSA. Seventy five per cent of emerging infections in the past two decades are zoonotic in origin.

Therefore, human-animal linkages play a key role in infectious-disease emergence. The spillover of pathogens from wildlife reservoirs and changing animal farming practices are both driving the emergence of infectious disease from animals.

In both immunocompetent (having a normal immune response) and immuno compromised (having an impaired immune system) individuals of both developed and developing countries, knowledge of linkages between zoonotic infection and chronic disease will help better define the true burden of illness due to zoonotic diseases.

Biotechnology advances are needed for identification of previously unrecognized zoonotic pathogens in the etiology of chronic diseases. Development of simple, rapid, economical, and user-friendly diagnostics for zoonotic disease, preferably at bedside or pen-side, with appropriate sensitivity and specificity to enable treatment and control of zoonotic pathogens is required.

Changing animal farming practices

Intensive animal farming practices produces large amounts of animal waste that may contain pathogens. These inadvertently amplify the growth and spread of pathogens, the genetic reassortment of new strains, including new strains of influenza in swine and poultry populations.

Antibiotics have been added to commercial animal feed as growth promoter, since the year 1950, and this practice has become established in many parts of the world. Studies have found that the patterns of antimicrobial resistance in human infections with Salmonella and other agents more closely parallel the use of antimicrobial agents in animals than in humans, suggesting that agricultural use of antibiotics has led to a human public health risk from antimicrobial-resistant pathogens.

Pathogens from wildlife populations

Wild animals serve as reservoir of many pathogens without causing significant morbidity or mortality. With increase human population, there is encroachment on wildlife habitats, and humans continue to make contact with wildlife through hunting or trade in wild animals. This increases the risk of pathogen spillover into human populations.

Hunters enter wildlife habitats for catching and butchering of wildlife species either for selling in low-biosecurity markets or for home consumption. In this practice, the hunters and their community are exposed to a range of viral and bacterial pathogens from nonhuman primates and other species.

Intensification of agriculture and wildlife reservoir spillover are often related. There was global spread of highly pathogenic avian influenza in poultry populations. The spread of the virus was due to the movement of the virus in wild bird populations, as well as the movement of poultry itself.

Lack of proper biosecurity measures at live-animal markets, backyard livestock and poultry production and processing and increased poultry production in these areas may also play a role in the amplification of novel strains of animal influenza.

Animals play the role as vectors of zoonotic diseases through a variety of potential pathways, including direct contact, tick and mosquito vectors, and the food supply. In this case, control of zoonotic disease would focus on animal control measures such as quarantine, culling, and animal vaccination.

Shared environmental risk of animals with humans would expand control measures to include managing landscape and land-use change to benefit both animal and human populations.