ROLE OF THE VETERINARIANS AND ONE HEALTH IN THE FIGHT AGAINST ZOONOSES
Dr. Smruti Smita Mohapatra
Junior Research Fellow,
Verghese Kurien Centre of Excellence (VKCoE),
Institute of Rural Management Anand,
Anand, Gujarat
https://www.pashudhanpraharee.com/847-2/
Introduction
One health is defined by the One Health Commission as “the collaborative effort of multiple disciplines to obtain optimal health for people, animals, and our environment.” The One Health Initiative Task Force (OHITF) defines one health as “the promotion, improvement, and defense for the health and well-being of all species by enhancing cooperation and collaboration between physicians, veterinarians, and other scientific health professionals and by promoting strengths in leadership and management to achieve these goals.” The one health approach plays a significant role in the prevention and control of zoonoses. 75% of new emerging human infectious diseases are defined as zoonotic, meaning that they may be naturally transmitted from vertebrate animals to humans. New and reemerging zoonoses have evolved throughout the last three decades partly as a consequence of the increasing interdependence of humans on animals and their products and our close association with companion animals. Zoonoses is the single most critical risk factor to human health and well-being, with regard to infectious diseases. This gives significant credence to the importance of examining health effects across species, in order to fully understand the public health and economic impact of such diseases and to help implement treatment and preventive programs by veterinarians. Thus one health concept is a broad term that covers a variety of subcategories identified as bioterrorism, animals as predictors for disease, and the psychological bonds that can exist between an animal and a human.
One Health approach
One Health issues include zoonotic diseases, antimicrobial resistance, food safety and food security, vector-borne diseases, environmental contamination, and other health threats shared by people, animals, and the environment. Considering the possible origin of the current pandemic, the intensification of research on high human activity and intense contact with wildlife, should become a priority in the prevention of emerging diseases. Potential new pandemics such as COVID-19 pose serious health threats in hotspots. The contact between wildlife and human activities can have consequences in rich countries. It is necessary to reunite the forces and capacities of all of the involved actors and entities to avoid chaos and lack of control in the case of new emerging zoonotic diseases. The knowledge obtained through monitoring eventual ecological/epidemiological changes and the experience of previous studies in all knowledge areas will be effective tools to predict, prevent, and anticipate outbreaks by impacting zoonotic diseases such as COVID-19. This summarizes the veterinarian’s role in public health, framed in the One Health concept.
Zoonoses: A global health concern
Zoonoses determine the status of the one health approach and its applications to zoonoses. Considering one health scopes, these were the common subject areas covered: zoonoses, agriculture, food safety, environmental health, and global health. These categories were condensed from a larger, more complex list provided by the One Health Initiative Task Force. One health is linked to agriculture, environmental health, zoonoses, global health and food safety. The scopes of global health and environmental health can be improved by prevention of the zoonoses, which produces an area of concern. The issues relating to one health, while in their genesis involved zoonoses and food safety, were identified as environmental and global health issues in the reporting and publications. While this shows evidence of the profound efforts to boost environmental and global knowledge about one health, it also demonstrated the limited body of knowledge of zoonoses, agriculture, and food safety.
Zoonoses, agriculture, and food safety are all interconnected topics in that they all directly impact the health of humans. In the last 30 years, there has been an average of one newly discovered emerging infectious disease every year. A total of 335 emerging infectious diseases were identified between 1940 and 2004. Considering that more than 60% of infectious diseases are zoonotic, they have an important and increasing impact on human health. Agriculture, livestock production, and food safety practices are intimately linked with the prevention and control of zoonoses through the one health approach. Developed countries, by virtue of their greater institutional facilities and veterinarians, train personnels and financial resources are able to address the issues of one health approach. This is extremely beneficial as it enables a nation to gain an awareness of one health initiatives and the added synergistic value of this approach. The One Health Initiative Task Force has reported that while the developed countries prevail in making one health discoveries, it is the developing countries that suffer the most from the effects of zoonoses. It has been estimated that 70% of the reasons for poverty in Africa can be attributed to poor livestock production practices. Zoonotic infections significantly impact animal production further jeopardizing human and animal livelihoods.
Role of the veterinarians
The one health approach, according to the One Health Initiative, has been utilized to accelerate biomedical research discoveries, enhance public health efficacy, expeditiously expand the scientific knowledge base, and improve medical education and clinical care. The increasing encroachment of people and livestock into wildlife habitats provided a multifaceted need to study bats and offer understanding for study at the human-wildlife interface. Bats are an important reservoir and vector for spread of a number of emerging infectious diseases and they are associated with zoonoses with global public health significance such as Lyssa, Hendra and Nipah viruses, SARS like coronaviruses, and Ebola and Marburg viruses. The importance of wildlife as reservoirs of human diseases has been widely recognized for most of the parasitic zoonoses, including American and African trypanosomiasis, leishmaniasis, giardiasis, cryptosporidiosis, balantidiasis, fascioliasis, opisthorchiasis, clonorchiasis, paragonimiasis, schistosomiasis, echinococcosis, taeniasis, diphyllobothriasis, sparganosis, dipylidiasis, trichinellosis, toxocariasis, strongyloidiasis, and Ancylostoma caninum and A. braziliense infections. Molecular phylogenetic methods used to examine the genetic diversity and species composition of these parasites in humans and their domestic and wild reservoir, paratenic, definitive, and intermediate host species have shown that they are in many instances identical. African trypanosomes identified in wildlife in the Serengeti in Tanzania and the Luangwa Valley in Zambia which harbour a wide range of trypanosomes are the same species which infect humans and livestock. The one health concept has successfully replaced the disease centered approach to zoonoses with a system based approach that aligns multiple disciplines, working locally, nationally, and globally, to attain optimal health for people, domestic, and wild animals and the environment.
Zoonotic diseases pose both major health threats and complex scientific and policy challenges, to which the social, cultural, and political norms and values are essential to address successful control outcomes. The need to employ one health is illustrated in the cases of H5N1 avian influenza in which control failed due to the lack of addressing the complex dynamics of zoonotic diseases. Rapid Response Briefing reported on the ebola haemorrhagic fever outbreak which occurred in Uganda in 2012. The one health approach, employing disease surveillance, management, and eradication through collaboration between veterinarians dealing with livestock and wild animal populations and ecologists examining ecosystem biodiversity and public health experts, may have yielded a more rapid resolution to the outbreak The application of the one health approach has been recognized as a critical need by international organizations as well as the preferred approach to address global health issues. The recent call for proposals for funding recognizes the lack of knowledge sharing and an artificial barrier that separates the fields of human and animal health. The Grand Challenges in Global Health specifically identified that advances in drug and vaccine discoveries for human diseases can be applied to provide tools and approaches for animal diseases that still plague developing countries. It is also noted that knowledge in veterinary medicine and animal nutrition and husbandry could provide insights into human nutrition and growth.
Veterinary microbiology, physiology, immunology, and behavioural ecology must be applied to asymptomatic animal hosts. They can demonstrate which mechanisms could explain the absence of clinical signs and can provide effective and applicable responses to humans. At the same time, they are specific animal models, which provide ideal conditions for the reproduction of the disease showing similarity to human responses and should be used to carry out vaccine and treatment tests before being applied to humans. Besides, prior knowledge of the etiologic agent, its intrinsic characteristics, and ecology can facilitate the faster development of vaccines and therapy drugs in cases of emergency and health risk. The probability of success in any zoonotic disease control/eradication programme should be a major consideration. Pre-requisites for success include: effective methods for stopping or reducing agent transmission, high socio-economic importance, epidemiological features that allow good case detection, good surveillance for measuring progress and providing information that can be used to make changes as required.
Coordinated and sustainable human and veterinary surveillance programmes for zoonoses and animal related hazards. Clearly epidemiology must be used as the primary guide for veterinary public health policies based on prevention. Surveillance is one of the key issues and is defined as the ‘ongoing scrutiny of all aspects of occurrence and spread of a disease that are pertinent to effective control, prevention and eradication’. Comparative medicine, in addition to in vitro analyzes, covers field studies in the prevention of zoonosis perspective for the development of research related to the control of zoonosis. One health encompasses zoonotic infections, food safety, and even health delivery systems. There is also an integrated epidemiological and economic framework for assessing zoonoses using a “one health” concept building on the medical focus of zoonoses. In recent times the one health concept has been expanded to encompass the health and sustainability of the world’s ecosystems. The one health approach considers inextricable linkages beyond the human, animal, and environmental interface. Collaboration between veterinary, medical, and public health professionals to understand the ecological interactions and reactions to flux in a system can facilitate a clearer understanding of climate change impacts on environmental, animal, and human health. Climate change causes issues such as emerging infectious diseases, food security, and national sustainability planning. These issues intensify the importance of interdisciplinary and collaborative research. Evidence for expanded application of one health compared to separate sectoral thinking is growing and this integrative thinking is increasingly being considered in academic curricula in schools of medicine, veterinary medicine and public health, clinical practice, ministries of health, livestock and agriculture, and international organizations. The one health approach to zoonoses however remains an average priority for health care professionals. The impact of zoonoses on animal health has been largely neglected but the effects on public health usually drive control initiatives on zoonoses. The zoonoses prioritization exercise must involve veterinarians who can train health professionals expanding the limited knowledge of infectious diseases identified zoonoses as an area of priority. Veterinarians can play a role in making the local public health agencies aware who are mostly unprepared and potentially unaware of their responsibility to be the initiator of the work on zoonotic disease information intelligence. The advancement of the one health approach has increased the discussion and reporting on the topic. There remains a lack of knowledge and application of the integrated approach to health care by the health care professionals. Reaching the goal of control, and elimination and/or ultimate eradication of zoonoses pose a significant challenge for the future. Standardized interlaboratory test validation, intersectoral collaboration and establishment of an international one health diagnostic platform are considered to be important strategies. The sharing of best practices on diagnosis of zoonoses and the further refinement of new, cheaper, multispecies tests which can be interpreted by minimally trained individuals could contribute to a greater level of intersectoral integration, control, and elimination of zoonoses. The future of one health is a one world approach with the continued effort towards integration of the contributing parts that form the health.
Conclusion
The one health approach continues to be a highly investigated concept, via the pursuit of scholarly resources involving the health of humans, animals, and the environment. The veterinarian needs to assume a position of leadership in research and actions that primarily involve prevention and surveillance, which must be undertaken as an important part of maintaining public health, especially related to emerging and re-emerging zoonoses. Successful public health interventions require the cooperation of human, animal, and environmental health partners. Professionals in human health (doctors, nurses, public health practitioners, and epidemiologists), animal health (veterinarians, paraprofessionals, agricultural workers) and environment (ecologists, wildlife experts) need to communicate, collaborate on, and coordinate activities. Other relevant players in a One Health approach could include law enforcement, policymakers, agriculture, communities, and pet owners. No one person, organization, or sector can address issues at the animal-human-environment interface alone. By promoting collaboration across all sectors, a One Health approach can achieve the best health outcomes for people, animals, and plants in a shared environment. There is a need to increase research on zoonoses, food safety, and agriculture and to improve the understanding of the one health concept. This could be achieved by introducing more scholarly resources in developing countries by the further development of the Internet and the free availability of online information on one health. The use of Massive Open Online Courses (MOOC) available to developing countries is now being offered to deliver courses on the approach and applications of one health. This is critical because most of the public health and economic impacts that occur within the concept of one health occur in developing nations. The lack of basic health infrastructure in developing countries means that everything else suffers as a result, namely, the environment, human, and animal health and well-being. The greatest acceptance of one health is seen where it is having significant impacts on control of infectious diseases. There is also a continuing need for further efforts towards integration with the global community serving as the unit of a one system approach. Practices such as zoobiquity and translational medicine are effectively applied in some countries with more stable economies for other diseases and would help to prevent zoonotic pandemics such as COVID-19. The exchange of experiences and the adoption of professional containment activities such as those which are customary in veterinary practice, like isolation and quarantine measures, could be useful. Veterinary practices are widely and rigorously used because they represent the main principles for preventing the entrance and spread of diseases in naïve animal populations. Surveillance measures represent the main strategy, considering these preventive needs. Active surveillance is important in the investigation of the potential pathogens of animals and the potentials of possible emergence in humans. Veterinarians are especially important in wildlife surveillance, which becomes a fundamental parameter in the control of emerging zoonoses because ecological changes, molecular variations of infectious agents, and wild animal-man interactions represent the main factors for the emergence of new pathogens. Therefore the collaboration between veterinary communities linked to the monitoring of wildlife and human medical communities is crucial in the development of preventive strategies against zoonoses and improving one health.
