One World, One Health, Prevent Zoonoses, Stop the Spread
Animals have played a vital role in the evolution of humans. The hunter-gatherers began domesticating animals for food, agriculture, transportation, war, security, recreational activities, etc. and gradually settled down. This resulted in increased contact of humans with animals and the sharing of habitat. With this, the transmission of diseases from animals to man and man to animals became frequent leading to the spread of zoonotic diseases. According to the World Health Organization (WHO), Zoonotic diseases are defined as diseases and infections that are naturally transmitted between vertebrate animals and man, and infections that are shared between vertebrates and man. Zoonotic pathogens may be bacterial, viral, parasitic, or unconventional agents and can spread to humans through direct contact or contaminated water, food, or the environment. Zoonotic diseases represent a major public health problem worldwide due to our close relationship with animals as companions, in agriculture, and in the natural environment. The most commonly encountered zoonotic diseases are as follows:
Bacterial : Anthrax, Leptospirosis, Brucellosis, Plague, Salmonellosis, etc.,
Viral : Rabies, Kyasanur Forest Disease, Influenza, Zika, Nipah, etc.,
Rickettsial : Scrub Typhus, Rocky Mountain Spotted Fever, Murine Typhus, etc.,
Helminth Borne : Taeniasis, Hydatidosis, Schistosomiasis, Leishmaniasis, etc.,
Protozoal : Toxoplasmosis, Trypanosomiasis, Leishmaniasis, etc.,
Ectoparasitic : Scabies, Myasis, etc.,
Fungal – Cryptococcus, Histoplasmosis, etc..
The risk factors precipitating the occurrence of zoonotic diseases are many and are in a state of continuous evolution. This evolution moves in conjunction with the changing societal and demographic patterns across the country with technological developments and fast communication, migration, and international travel and trade including globalization of trade in animals and animal products enhancing the opportunity for pathogens transcending national and international borders, leading to extensive spread of diseases around the globe. In India, population pressure is a major factor contributing to deforestation because of the expansion of residential areas, urbanization, industrialization, and highways across the country leading to a decline in biodiversity.
India went for massive irrigation projects since independence contributing to an increase in food grain production from merely 51 million tons (1950/51) to over 6 times rise to 314 million tons (2022). This has resulted in massive ecological/habitat loss with an impact on hosts, agents, and the environment of infections/zoonotic diseases. There is evidence that global warming increases the population of insects that harbor the organisms that spread various diseases. Factors like natural migration of animals, especially migratory birds, climate change, ecological changes, microbial adaptation, disasters, political conflicts, travel and tourism, and human demographics and behavior have led to the foundation of endemic, re-emerging, and emerging diseases with epidemic potential.
Zoonotic diseases have been escalating globally as well as in India. Of 1407 human pathogens, 58% (816) are zoonotic. These include 538 bacteria and rickettsia, 317 fungi, 287 helminths, 208 viruses/ prions, and 57 protozoa. The study also highlighted that as many as 177 (13%) of the total pathogens were emerging or reemerging, and of these 130 (75%) were classified as zoonotic. Usually, Emerging infections are more alarming because humans have limited information about their origin and many of their epidemiological features remain mysterious. The economic impact is also not well described. Zoonotic diseases, being a global problem have received priority attention from the WHO and other international organizations such as the Food and Agricultural Organization, and the World Organization for Animal Health. Through the Global Early Warning System for Major Animal Diseases including zoonoses (GLEWS) all three agencies jointly work together by combining and coordinating alert mechanisms to assist in early warning, prevention, and control of animal disease, including zoonoses, through data sharing and risk assessment. Implementing harmonized and coordinated strategies through effective health governance, at international, regional, and national levels is the only way to combat these petrifying problems.
With increasing socio-economic interdependence and increased mobility between and within countries, health security has become vulnerable to being compromised, with a resultant impact on global health. WHO defines Global public health security (GPHS) as “the activities required, both proactive and reactive, to minimize the danger and impact of acute public health events that endanger people’s health across geographical regions and international boundaries.” Efforts have been initiated to unite the whole world through launching various international initiatives for concerted and committed action. Two such initiatives at the forefront are the Global Health Security Agenda (GHSA) and the One World One Health approach. Global Health Security Agenda (GHSA) is a worldwide effort to build up the capacity of countries to prevent, detect, and respond to infectious disease threats. As per WHO “One Health Approach” has been defined as “an approach to designing and implementing programs, policies, research, and legislation in which multiple sectors communicate and work together to achieve better public health outcomes.” It is a collaborative, multisectoral, transdisciplinary approach, which works at the local, regional, national, and global levels. The goal of One Health is to achieve optimal health outcomes while recognizing the interconnection between people, animals, plants, and their shared environment. One Health is concerned with multiple issues which include zoonotic diseases, food safety and food security, environmental contamination, vector-borne diseases, antimicrobial resistance, and other health threats shared by people, animals, and the environment.
Health of the humans relies on well-functioning ecosystems, which provide fresh water, clean air, and food security, medicines, as well as limit disease and stabilize climate. As zoonoses involve both animals and humans, this showcases a “one health” approach to address animal health, human health, and the environment in an integrated manner.
In India, an active effort is to reinforce surveillance for early diagnosis and effective, appropriate containment. The National Centre for Disease Control plays an important role in strengthening capacity across the country and bringing together epidemiologists, microbiologists, veterinarians, entomologists, etc., to effectively launch required multi-sectoral action to address zoonotic diseases. Prevention methods for zoonotic diseases vary for each pathogen. However, numerous practices are recognized as effective in reducing threats at the community and personal levels. Safe and appropriate guidelines for animal care in the agricultural sector help to minimize the potential for food borne zoonotic disease outbreaks through foods such as meat, eggs, dairy, or even some vegetables. Standards for clean drinking water and waste removal and protections for surface water in the natural environment are also important and effective. Education campaigns to promote hand washing after contact with animals, awareness regarding indiscriminate use of antimicrobials and other behavioral adjustments can reduce community spread of zoonotic diseases when they occur. This requires a close collaboration between various sectors especially veterinarians and health personnel to put in place efficient preventive practices. There is also a need for strengthening surveillance with a well-built laboratory network to pick up diseases both in humans and animals early to launch prompt containment action before an outbreak becomes an epidemic. The “one health” approach brings veterinarians, health care providers, and other sectors. Apart from that, it also requires robust public health facilities, trained frontline workers, and early diagnosis, treatment, prevention, control, and management of zoonotic diseases. The measures of early detection, prevention, and containment need to be integrated into planning at a local level, i.e., state program implementation plans starting from the district level upward under the National Health Mission.
Dr. Savita R Kashappanavar,
Assistant Professor,
Department of Veterinary Public Health and Epidemiology,
Veterinary College Bidar,
Karnataka.
