ONE WORLD, ONE HEALTH: PREVENT ZOONOSES, STOP THE SPREAD
*Dona Mary Eldhose1, Aravindh S2, E. Angelin Shyona3
- Department of Animal Nutrition, College of Veterinary and Animal Science, Pookode
- Department of Veterinary Physiology, OUAT, Odisha
- Livestock Product Technology, West Bengal University of Animal & Fishery Sciences
Introduction
The One Health approach is a collaborative and interdisciplinary strategy that unites multiple sectors to promote optimal health outcomes. By recognizing the intricate connections between humans, animals, plants, and the environment, this approach aims to address health threats at their intersection. Through a unified and sustainable approach, One Health seeks to balance and optimize public and animal health, food security, ecosystem sustainability, and fair-trade practices. This concept has its roots in the work of Rudolf Virchow, a 19th-century pioneer in the field. The One Health approach facilitates collaborative disease surveillance, outbreak control, and prevention of zoonotic diseases, enhancing food safety and security and reducing antimicrobial resistance.
Global public health concerns are posed by zoonoses, which are infections that are spread from animals to humans. All kinds of animals, including household pets, livestock, and wildlife, can carry these infectious diseases. Humans can contract them by direct contact, eating or drinking contaminated food or water, or by being bitten by mosquitoes or ticks. Notably, over 75% of emerging disease pathogens are zoonotic, with 60% originating from domestic or wild animals and 80% posing a bioterrorism concern. These pathogens can spread through direct contact, contaminated food and water, or environmental exposure, highlighting the importance of a unified approach to protect human and animal health.
Effective preventive measures are vital, as demonstrated by zoonotic outbreaks like the recent COVID-19 pandemic, which is thought to have started in bats.
Veterinary medicine, public health, ecology, and global governance are just a few of the fields that must be included in an all-encompassing, multidisciplinary approach to zero-day diseases. To avoid disease spread, it is important to implement sustainable practices in agriculture and wildlife management, improve biosecurity in animal farms and markets, and conduct stringent surveillance to identify possible outbreaks early. Additionally, educating communities about safe interactions with animals and adopting hygienic practices in food handling are pivotal in reducing transmission risks. Due to the fact that zoonotic illnesses transcend national boundaries and species distinctions, international collaboration and information exchange are essential in the fight against them. In an increasingly linked world, we can lessen the effects of zoonoses and protect public health by emphasizing preventive measures, funding research, and encouraging cooperation between the human and animal health sectors.
The Role of Environmental Factors in Zoonotic Disease Emergence
Climate change, deforestation, and environmental pollution are altering ecosystems, causing the spread of zoonotic hosts and vectors. Rising temperatures are stimulating the reproduction of pathogens and vectors, while environmental stress is weakening wildlife immunity, leading to the shedding of pathogens into the environment. The decline of biodiversity is linked to an increased risk of zoonotic diseases, compromising the dilution effect that reduces pathogen spread. Environmental changes are attracting animals to urban habitats, creating new opportunities for disease transmission. The distribution and behavior of mosquito vector species are being affected by environmental changes, leading to the expansion of zoonotic malaria in Southeast Asia. Deforestation is creating ideal environments for mosquito vectors, bringing infected macaques into close proximity with humans. Climate change is also increasing the transmission of foodborne pathogens, as warmer temperatures optimize their growth rate. Extreme weather events are contaminating water sources with harmful pathogens, nutrients, and toxins, elevating the disease burden due to waterborne pathogens.
Emerging and re-emerging waterborne zoonotic pathogens, such as Campylobacter, E. coli O157:H7, Cryptosporidium, and Leptospira, have been documented in recent decades. The interplay between human activities, environmental changes, and animal-mediated diseases demands urgent attention to mitigate the risks of zoonotic disease transmission.
The Impact of Human Activities on Zoonotic Disease Transmission
Habitat destruction and fragmentation, driven by human activities like agriculture, urbanization, and deforestation, lead to an increase in species that thrive in human-dominated environments. This, in turn, enhances human contact with wildlife, facilitating the transmission of zoonotic pathogens. Land use changes and wildlife exploitation are key drivers of biodiversity loss, which also fuels the spread of zoonotic diseases. In urban areas, the dynamics of zoonotic parasite transmission are not well understood, but factors like abundant food resources and the presence of pets may play a significant role. Urbanization leads to a higher frequency of contact between humans and wildlife, increasing the risk of parasite transmission. Deforestation alters wildlife communities, increasing the potential for zoonotic spillover. The growth in human population and deforestation have contributed to the rise in zoonotic outbreaks, particularly in tropical regions. Deforestation disrupts natural habitats, leading to the migration of animals like bats into new areas, increasing human contact with zoonotic viruses. The relocation of animals from their natural habitats to urban areas, such as in petting zoos and tourist parks, creates a zoonotic risk factor similar to deforestation. The transportation and sale of infected animals away from their native regions also increase the risk of zoonotic transmission, allowing pathogens to switch hosts.
Prevention and Control Measures for a Healthier World
Prevention is defined as inhibiting the introduction of a disease agent into an area, a specific population group or an individual. Control efforts consist of steps taken to reduce a disease problem to a tolerable level and maintain it at the level. Safe and appropriate guidelines for animal care in the agricultural sector help to reduce the potential for foodborne zoonotic disease outbreaks through foods such as meat, eggs, dairy or even some vegetables. Standards for clean drinking water and waste removal, as well as protections for surface water in the natural environment, are also important and effective. Education campaigns to promote handwashing after contact with animals and other behavioral adjustments can reduce community spread of zoonotic diseases when they occur. Eradication is the final step in a disease control program. It consists of the elimination of a disease producing agent from a defined population or geographical area.
Vaccination
Vaccines offer a dual benefit, protecting both the individual who receives them and the broader community. Widespread immunization significantly reduces the likelihood of non-vaccinated individuals encountering harmful pathogens, thereby breaking the chain of disease transmission. This phenomenon, known as ‘herd immunity,’ relies on a critical mass of immunized individuals to safeguard public health. The most effective vaccines boast a triple advantage: long-term protection, cost-effectiveness, and safety, making them easy to implement on a large scale. However, the anti-vaccine movement poses a significant challenge to immunization efforts, spreading misinformation and fueling vaccine hesitancy. To combat this, governments must launch targeted information campaigns to address public concerns, dispel misconceptions, and counter harmful ‘fake news’ about vaccines, ultimately promoting a culture of vaccination and public health.
Development of new antimicrobial drugs
Overuse of antibiotics in human and veterinary medicine has led to the evolution of resistant infections, endangering the efficacy of therapy. Because of the agriculture sector’s significant reliance on antibiotics, the issue has been allowed to persist and resistant bacteria have been able to enter the food chain. A comprehensive approach is necessary to fight this situation. This involves educating stakeholders about the dangers of antibiotic resistance, encouraging the prudent use of antibiotics, and funding creative research. Together, we can find ground-breaking ways to stop the spread of infections that are resistant to drugs and protect public health. In this quest, it is imperative to adopt sustainable agriculture techniques, alternative medicines, and robust monitoring systems.
Reduction of contact with wildlife and livestock
Animal-to-human pathogen transmission is frequently associated with human behaviors that are motivated by cultural and economic motives, such as intense animal husbandry, poaching, and environmental degradation. It is critical to have policies in place that restrict human connection with wild animals and livestock, such as sustainable agriculture methods, environmentally friendly land use, and responsible wildlife management, in order to lower the chance of new infectious diseases arising in people. We can prevent the spread of disease and safeguard public health by implementing these measures.
Biodiversity preservation and containment of climate change
The microbial landscape is greatly impacted by the dynamic interactions that occur in the environment between humans, animals, and microorganisms. These interactions affect the distribution, abundance, and diversity of microorganisms. In a similar vein, microbes influence the distribution, behavior, and abundance of animal species, hence modifying the dynamics of ecosystems, including the interactions between predators and prey. The ecology of pathogens and the genesis of infectious diseases are influenced by these complex interactions. Thus, maintaining the equilibrium of host-pathogen interactions, lowering the likelihood of infectious disease outbreaks, and fostering ecological resilience all depend on sustaining biodiversity.
Reservoir Neutralization
Other sources of infection gradually diminish in importance or vanish if the reservoir’s infection can be eliminated. Three techniques are employed to neutralize the reservoir: eliminating sick persons, making infected individuals “non shedder,” and modifying the surroundings. A herd’s infection can be eradicated by testing the animals and killing those that test positive. Equine dourine and glanders, as well as bovine brucellosis and tuberculosis, have all been effectively managed with this approach. Mass treatment is an additional technique to neutralize the reservoir by eliminating contaminated individuals. Typically, mass therapy is limited to a geographical setting where all animals or humans who may be affected are treated without first undergoing tests to determine who is actually infected. Providing sufficient restroom facilities in conjunction with education would prevent the spread of Taenia saginata from feedlot employees to cattle.
Reducing Contact Potential
Reducing the likelihood of contact is a fundamental strategy for preventing the direct transfer of an infectious agent from an infected person to a vulnerable host. Three strategies are employed: population control, quarantine of potentially infected individuals, and isolation and treatment of patients. Two benefits come from isolating a sick, clinically ill animal: it lessens the likelihood of the animal coming into contact with a vulnerable person and makes treatment and disinfection easier. This strategy has major shortcomings and frequently fails since it relies on early and accurate diagnosis from efficient disease control programs centered on isolating and treating individuals to avoid the spread of infectious disease agents. Programs for population control are additional strategies for lowering contact. Dog feces leave behind ascarid ova at parks and beaches with kid-friendly sandboxes. If consumed, these ova can produce visceral larvae migrans (VLM) and hookworm larvae that can pierce the skin and produce coetaneous larva migrans (CLM). Although controlling cat mobility is significantly more challenging, CLM, VLM, and toxoplasmosis are additional issues associated with cats as a source of soil contamination.
Conclusion
A multifaceted strategy that incorporates scientific research, public health initiatives, and international collaboration is needed to prevent zoonoses in the modern world. We can successfully reduce the danger of zoonotic disease outbreaks by encouraging cooperation between the human and animal health sectors, improving surveillance systems, and supporting sustainable farming practices. It is also essential to educate and raise public knowledge on the proper care of animals and the consumption of animal products. In the end, preventing zoonoses from endangering both human and animal populations in our globalized society requires proactive steps and international cooperation. It also establishes network among public health, medical, veterinary laboratories, and research centres working with zoonotic pathogens.
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