ONE WORLD, ONE HEALTH: PREVENT ZOONOSES: THE ROLE OF ANIMAL AGRICULTURE IN ZOONOTIC DISEASE TRANSMISSION
Dr. Yashas R Kumar
Veterinary Pathologist
(BVSc&AH, MVSc., PhD, PGDOH., PGDAW)
Southern Regional Disease Diagnostic Laboratory (SRDDL)
Institute of Animal Health and Veterinary Biologicals (IAH&VB)
Hebbal Bangalore-560024, Karnataka
Abstract:
Zoonotic diseases, which are transmissible from animals to humans, pose a significant threat to public health globally. Animal agriculture plays a critical role in the transmission of zoonotic pathogens, as many of these diseases originate in animals raised for food production. It is crucial to adopt a “One world, One health” approach. “One world, one health” recognizes the interconnectedness between human health, animal health, and the environment. This article aims to provide an overview of the role of animal agriculture in zoonotic disease transmission and the measures that can be taken to prevent the spread of these diseases. The article will explore the link between animal agriculture practices, such as intensive farming and the use of antimicrobials, and the emergence and transmission of zoonotic diseases. It will also highlight the importance of One Health, a collaborative approach involving human, animal, and environmental health, in preventing zoonotic diseases. Understanding the connection between animal agriculture and zoonoses, appropriate interventions can be implemented to protect both human and animal health. By adopting a “One world, one health” approach, we can better understand and mitigate the risks associated with zoonotic diseases
Keywords: One world, One Health, Zoonoses
Introduction
Zoonotic diseases are infectious diseases that can be transmitted between animals and humans. These diseases have significant impacts on public health, causing illness, death, and economic losses. Animal agriculture plays a crucial role in the transmission of zoonotic diseases due to the close contact between humans and animals, as well as the conditions in which animals are raised and managed (Gibbs, 2014).
One of the primary ways that zoonotic diseases are transmitted from animals to humans in animal agriculture is through direct contact. Farmers, veterinarians, and other workers in the industry are in close proximity to animals on a daily basis, increasing their risk of exposure to zoonotic pathogens. These pathogens can be transmitted through contact with bodily fluids, such as saliva, blood, and faeces, as well as through contaminated surfaces and equipment. Examples of zoonotic diseases transmitted through direct contact include brucellosis, leptospirosis, and Q fever (Karesh et al.,2012).
In addition to direct contact, zoonotic diseases can also be transmitted through the consumption of contaminated animal products. Foodborne zoonoses, such as salmonellosis and campylobacteria’s, are a significant public health concern, with millions of cases reported worldwide each year. These diseases can be contracted by consuming raw or undercooked meat, eggs, dairy products, and other food items that have been contaminated with zoonotic pathogens (FAO,2021). Improper food handling and inadequate hygiene practices during the processing and preparation of animal products can further contribute to the spread of these diseases.
Furthermore, the crowded and often unsanitary conditions in which animals are raised in large-scale animal agriculture can promote the transmission of zoonotic diseases. Factory farms and concentrated animal feeding operations (CAFOs) house large numbers of animals in close quarters, creating an ideal environment for the rapid spread of infectious diseases. Factors such as poor ventilation, inadequate waste management, and high stocking densities can increase the risk of zoonotic disease transmission among animals. This can lead to outbreaks of diseases such as avian influenza, swine flu, and foot and mouth disease, which can have devastating consequences for both animal and human health (Alexander et al.,2015).
The use of antimicrobial agents in animal agriculture is another important factor contributing to the transmission of zoonotic diseases. The overuse and misuse of antibiotics and other antimicrobial drugs in livestock production can lead to the development and spread of antimicrobial resistance. This can make infections in both animals and humans more difficult to treat, increasing the severity of zoonotic diseases and limiting the effectiveness of available treatments. Additionally, the use of antibiotics in animal agriculture can disrupt the balance of the microbial ecosystem in animals, potentially leading to the emergence of novel zoonotic pathogens.
In order to prevent zoonotic disease transmission in animal agriculture, comprehensive measures need to be implemented. This includes implementing strict biosecurity protocols to minimize the risk of disease introduction and spread. This can include measures such as adequate quarantine and isolation of new animals, routine vaccinations, and regular monitoring of animal health. Hygiene and sanitation practices should also be emphasized, including proper handwashing, proper waste management, and regular cleaning and disinfection of animal housing and equipment (Kariuki S, et al. 2015).
Furthermore, there is a need to promote responsible use of antimicrobial agents in animal agriculture. This includes adhering to appropriate dosage regimens, avoiding the use of antibiotics as growth promoters, and only using them under veterinary guidance and prescription. It is also important to invest in research and development to develop alternative strategies for disease prevention and treatment in animal agriculture, such as vaccines and probiotics.
Education and awareness are also crucial in preventing zoonotic disease transmission in animal agriculture. Farmers, workers, and consumers need to be educated about the risks associated with zoonotic diseases, as well as proper hygiene and food safety practices. This can be done through training programs, workshops, and public health campaigns (Kariuki S, et al. (2015)
Literature Study
Methods:
This literature study was conducted through a systematic search of scientific databases, including PubMed, Scopus, and Google Scholar. The search terms used included “zoonotic diseases,” “animal agriculture,” “zoonotic disease transmission,” “One Health,” and specific zoonotic diseases associated with animal agriculture. Relevant articles from peer-reviewed journals were selected based on their relevance to the topic and the inclusion of up-to-date information.
Results and Discussion:
1.Zoonotic Diseases Associated with Animal Agriculture:
A. Avian Influenza (Bird Flu): Avian influenza is a zoonotic disease that primarily affects birds but can also infect humans. Poultry farming, especially in densely populated conditions, is a significant source of avian influenza transmission to humans. To prevent the transmission of avian influenza from birds to humans, strict biosecurity measures should be implemented in poultry farms. This includes maintaining high standards of hygiene, separating different bird species, and minimizing contact between birds and wild birds or other animals that may carry the virus. Vaccination of poultry against avian influenza is also an important measure to control the spread of the virus. Regular monitoring and surveillance of avian populations can help identify and contain outbreaks early, reducing the risk of transmission to humans. In the case of a suspected or confirmed outbreak of avian influenza in birds, culling of infected or exposed birds is often carried out to prevent the further transmission of the virus. This should be done in a humane and controlled manner, taking into consideration the welfare of the animals. Public education and awareness campaigns are crucial in ensuring that individuals are informed about the risks of avian influenza and understand the importance of proper hygiene practices and precautions (FAO,2021). This includes avoiding direct contact with sick or dead birds, washing hands thoroughly after handling poultry or eggs, and ensuring that poultry and eggs are properly cooked before consumption (Smolinski, 2003).
In conclusion, avian influenza is a zoonotic disease that primarily affects birds but can also infect humans. Poultry farming, particularly in crowded conditions, is a significant source of transmission to humans. It is essential to implement proper biosecurity measures, including vaccination and regular monitoring, to prevent outbreaks and minimize the risk of transmission. Public education and awareness are also crucial in reducing the spread of the virus. By taking these measures, we can effectively control avian influenza and protect both human and bird populations from its impact.
b) Bovine Tuberculosis: Bovine tuberculosis is a zoonotic disease caused by Mycobacterium bovis, primarily affecting cattle. However, humans can acquire the infection through consumption of contaminated milk or meat from infected animals. Bovine tuberculosis is a global health concern, particularly in regions where farming and livestock production are prevalent. It can have significant economic consequences as it affects the productivity and trade of livestock.
Additionally, the treatment of bovine tuberculosis in both animals and humans can be challenging, requiring prolonged antibiotic therapy. In cattle, bovine tuberculosis is primarily transmitted through direct contact with infected animals, inhalation of bacteria in the air, or ingestion of contaminated feed or water. Infected animals may exhibit symptoms such as coughing, weight loss, weakness, and reduced milk production. However, some infected animals may not show any visible signs, making it difficult to identify and control the disease. In humans, bovine tuberculosis generally affects the lungs, similar to other forms of tuberculosis. The symptoms can include persistent cough, chest pain, weight loss, fatigue, and night sweats. The disease can be severe and may lead to complications if left untreated.
The control and prevention of bovine tuberculosis involve various measures, including testing and surveillance programs, movement restrictions of infected animals, and culling of infected herds. These efforts aim to identify and eliminate infected animals to prevent the spread of the disease within animal populations. Regular testing of cattle herds is crucial to detect infected animals early and prevent the disease from spreading. While bovine tuberculosis primarily affects animals, it can also infect humans through the consumption of unpasteurized milk or undercooked meat from infected animals. The bacterium can survive in raw dairy products and meat, posing a risk of transmission to humans. When humans acquire bovine tuberculosis, it is referred to as zoonotic tuberculosis (WHO, 2021).
In conclusion, bovine tuberculosis is a zoonotic disease primarily affecting cattle, but it can also infect humans through the consumption of contaminated milk or meat. Control measures such as testing, surveillance, movement restrictions, and culling of infected herds are crucial in controlling the spread of the disease in animals. Similarly, proper food safety practices, including pasteurization of milk and thorough cooking of meat, are essential to prevent transmission to humans.
c) Brucellosis: Brucellosis is a bacterial zoonotic disease that can be transmitted to humans through direct contact with infected animals or consumption of contaminated animal products, such as unpasteurized milk or cheese. The bacteria can enter the body through various routes, including inhalation, ingestion, or contact with broken skin or mucous membranes. Dairy workers, veterinarians, farmers, and individuals who consume unpasteurized dairy products are at a higher risk of contracting the disease. It is important to note that Brucella does not spread person-to-person, except in rare cases of organ transplantation or breastfeeding. Prevention and control measures for brucellosis are primarily focused on controlling the disease in livestock. Vaccination of livestock animals is an essential strategy to prevent the spread of Brucella bacteria. Testing and surveillance programs are also implemented in many countries to detect and cull infected animals. Infected animals should be separated from healthy ones to minimize transmission (De Figueiredo et al., 2015).
For humans, prevention mainly involves practicing good hygiene and avoiding exposure to infected animals or their products. This includes pasteurizing milk and dairy products, thoroughly cooking meat from potentially infected animals, and wearing protective clothing when handling animals or their tissues. Diagnosing brucellosis in humans can be challenging as the symptoms are non-specific and may resemble other diseases.
The diagnosis typically involves a combination of clinical evaluation, blood tests, and sometimes imaging tests to detect signs of organ involvement. Culturing the bacteria from the blood or other body fluids can confirm the diagnosis. Efforts to control brucellosis require a One Health approach, considering the interconnection between animal health, human health, and the environment. Collaboration between the veterinary, medical, and agricultural sectors is crucial for implementing effective control measures and raising awareness about the disease and its prevention (Mantur, and Amarnath, 2008).
d) Salmonellosis: Salmonellosis is a common bacterial zoonotic disease transmitted to humans through the consumption of contaminated animal products, including eggs, poultry, and dairy. The disease is caused by bacteria known as Salmonella, which can be found in the intestines of infected animals. When contaminated animal products are consumed, the bacteria can enter the human body and cause an infection.
Salmonellosis is a global health concern, with millions of cases reported each year. In addition to preventing transmission from animal products, it is also important to prevent salmonella contamination in food processing and food service establishments. Efforts to reduce salmonellosis also involve implementing strategies to control and prevent salmonella infections in animals. This includes measures such as vaccination programs, improving animal housing and hygiene conditions, and implementing strict biosecurity measures in farms and livestock operations.
Prevention and control efforts involve personal hygiene practices, safe food handling and preparation, and implementing measures to control salmonella infections in animals. Ongoing surveillance and regulation are crucial to prevent and respond to outbreaks of salmonellosis and protect public health (Otte, J., et al. 2007).
- Impact of Intensive Farming Practices:
Intensive farming practices in animal agriculture, such as overcrowding, poor hygiene, and the use of antibiotics, can contribute to the emergence and spread of zoonotic diseases. Overcrowding increases the likelihood of disease transmission due to the close contact between animals, facilitating the spread of pathogens. Poor hygiene practices, including inadequate waste management and contaminated water sources, further contribute to the spread of zoonotic pathogens. Additionally, the misuse and overuse of antibiotics in animal agriculture can lead to the development of antimicrobial resistance, compromising the effectiveness of treatment for zoonotic infections
- Preventive Measures in Animal Agriculture:
– Improved Biosecurity: Implementing strict biosecurity measures, such as controlling animal movement, limiting human access to animal facilities, and maintaining appropriate hygiene standards, can help prevent the introduction and spread of zoonotic diseases in animal agriculture.
– Vaccination Programs: Vaccination plays a crucial role in preventing zoonotic diseases in animals. Vaccinating animals against diseases such as avian influenza and brucellosis can significantly reduce the risk of transmission to humans.
– Health Monitoring and Surveillance: Regular health monitoring and surveillance of animals in agriculture settings can help identify and control zoonotic diseases at an early stage. Prompt detection and implementation of control measures limit the spread of zoonotic pathogens.
– Improved Food Safety Practices: Ensuring safe food practices, such as proper handling and storage of animal products, and promoting the consumption of properly cooked animal products can reduce the risk of zoonotic infections in humans.
Conclusion:
Zoonotic diseases transmitted through animal agriculture pose a significant threat to global public health. Understanding the dynamics of zoonotic disease transmission and implementing preventive measures in animal agriculture are crucial steps in preventing and controlling these diseases. The One World, One Health approach emphasizes the need for collaborative efforts between human, animal, and environmental health sectors to address zoonotic diseases effectively. By implementing improved biosecurity, vaccination programs, health monitoring, and promoting food safety practices, the risk of zoonotic disease transmission can be minimized in animal agriculture settings. Continued research, surveillance, and education are essential for ongoing prevention and control efforts to ensure the health and well-being of both animals and humans in a One Health framework.
References:
- Alexander KA, et al. (2015). Wildlife and Emerging Zoonotic Diseases: The Biology, Circumstances, and Consequences of Cross-Species Transmission. Science. 2015 Jul 3; 353(6294): 1044-1051.
- Centers for Disease Control and Prevention (CDC) – Salmonella: https://www.cdc.gov/salmonella/index.html
- Centers for Disease Control and Prevention. (2018) Brucellosis. Available from: https://www.cdc.gov/brucellosis/index.html. Retrieved on 15-10-2020.
- De Figueiredo, P., Ficht, T.A., Rice-Ficht, A., Rossetti, C.A. and Adams, L.G. (2015) Pathogenesis and immunobiology of brucellosis: Review of Brucella-host interactions. J. Pathol., 185(6): 1505-1517.
- Food and Agriculture Organization of the United Nations (FAO). (2021)
- Food and Agriculture Organization of the United Nations. (2009). The Contribution of Agriculture to the Development and Spread of Antimicrobial Resistance: Briefing Paper.
- Gibbs, E.P.J. (2014). The Evolution of One Health: A Decade of Progress and Challenges for the Future. Veterinary Record, 174(4), 85-91.
- Karesh WB, et al. (2012). Ecology of Zoonoses: Natural and Unnatural Histories. Lancet. 2012 Dec 1; 380(9857): 1936-1945.
- Kariuki S, et al. (2015). Zoonotic Infections in Women: A Systematic Review. PLoS One. 2015 May 8; 10(5): e0128651.
- Kupferschmidt, K., & Cohen, J. (2020). Race to find COVID-19 treatments accelerates. Science, 367(6485), 1412-1413.
- Mantur, B.G. and Amarnath, S.K. (2008) Brucellosis in India a review. Biosci., 33(4): 539-547.
- Otte, J., et al. (2007). Zoonoses and the Human-Animal-Ecosystems Interface. OIE Revue Scientifique et Technique, 26(1), 35-50.
- Smolinski, M.S., et al. (2003). Infectious Diseases: Economic, Political and Social Impacts. Emerging Infectious Diseases, 10(3), 593-597.
World Health Organization. (2021). Zoonotic Diseases: Key Facts. Retrieved from https://www.who.int/news-room/fact-sheets/detail/zoonotic-diseases
