EXPLAINER

What Asia Can Do to Protect against Animal-Borne Diseases

Zoonotic diseases can wipe out entire subsectors of livestock, posing a serious threat to public health. Photo credit. ADB.
Zoonotic diseases can wipe out entire subsectors of livestock, posing a serious threat to public health. Photo credit. ADB.

Preventing and controlling the spread of deadly diseases from animals to humans require a collaborative, multisectoral, and transdisciplinary approach.

Introduction

Asia is a hotspot for zoonoses—diseases that can be transmitted by animals to humans. Every year, animal-borne diseases cause 2.5 billion cases of sickness and 2.7 million deaths among humans. The spread and emergence of zoonoses pose a threat to the gains made in achieving the health targets under the Sustainable Development Goals.

The most harmful routes of zoonotic infection are handling and consuming infected food that comes from animals. Tackling food safety concerns is one of the effective pathways to control zoonotic diseases. Better monitoring of health threats and proper care of livestock and their environment contribute to improving food safety.

Recognizing its importance in improving regional health security, the Asian Development Bank has identified food safety as a priority area to support rural development and food security.

Figure 1: Transmission of Zoonoses

How Do Animals Pass Diseases to Humans?

Zoonoses (zoonosis, singular) account for 60% of infectious diseases affecting humans. These diseases are caused by a range of pathogens, such as viruses, bacteria, fungi, and parasites. Of the 1,415 pathogens known to infect humans, 61% are zoonotic.

They are spread through direct contact or though food, water, and the environment. Direct transmission from wild and farmed animals to humans is through media, such as air, or through bites and saliva. Infection can also occur via an intermediate species, referred to as a vector or carrier. Eating food contaminated with pathogenic bacteria, viruses, or parasites is the most potent zoonotic infection. The most significant foodborne pathogens are Escherichia coli O157:H7, Campylobacter, Caliciviridae, Nipah virus and Salmonella. Eggs, seafood, meat, dairy, and some vegetables are common foods linked to zoonotic contaminations.

Why Are Zoonoses a Concern for Asia?

Outbreaks of zoonotic diseases, such as Ebola virus, severe acute respiratory syndrome (SARS), avian influenza, and swine flu Influenza H1N1, have recently galvanized the attention of the global community to these public health emergencies. Most emerging zoonotic diseases often originate from the South and Southeast Asian subregions, such as SARS in the People Republic of China (PRC) in 2002, and Nipah virus in Malaysia in 1999 and Bangladesh in 2001.[1] In the last few decades, there have been three highly pathogenic influenza virus pandemics, two of them originated in Asia. These are  Asian influenza (H2N2) in 1957, H3N2 in Hong Kong, China in 1968, and swine-origin influenza A (H1N1) virus in 2009, initially detected in humans in Mexico. 

Trends in Globalization Accelerate the Spread of Disease

Figure 2: Acceleration of Zoonoses

The factors exacerbating the emergence, reemergence, and spread of zoonoses are related to global trends. These include climate change, population growth, antimicrobial resistance, weak health systems, deforestation, intensive farming systems, rapid urbanization, expansion of international travels, and increased agriculture trade. These compound challenges in anticipating and detecting zoonoses, and affect the effectiveness of the response to food-borne threats to human health. In addition to these factors and weak regional health systems, disease outbreaks travel quickly, posing a serious threat to public health. For example, the H1N1 outbreak started in Mexico in 2009, it spread globally, and the World Health Organization declared its first ever "public health emergency of international concern" in 2010. The SARS outbreak in 2003 devastated the Asia and Pacific region’s tourism and aviation sectors.

Most of the zoonotic pathogens have reservoirs in wild animals. Habitat destruction, climate change and other environmental factors have contributed to increased contact between wild and farmed animals and given rise to new zoonotic diseases.

There have been substantial increases in consumption of animal products in the last few decades, mostly in Asia and the Pacific. With the increased demand, generally livestock are raised in more confined spaces with less diversity in the gene pool. These production systems are associated with the overuse and misuse of antimicrobial medicines and growth hormones in animals. These factors result in selection and spread of antimicrobial resistance, further increasing the emergence of zoonotic diseases. Traces of these excessively used antibiotics then enter the food chain, exacerbating antibiotic resistance in humans. The World Bank estimates that antimicrobial resistance would reduce the gross domestic product of the world by over 3.5% annually. By 2050, cumulative impact could be $100 trillion and 10 million deaths annually.

Prevention Is More Cost-Effective

Zoonotic diseases are a major threat to society; they can affect entire sectors of the livestock and reduce human capital. Direct costs include lower animal production and higher public health costs. At the height of avian influenza, chicken production was reduced by over one third in the PRC. During the avian influenza outbreak in Viet Nam in 2009, 12% of the total annual poultry stock (some 50 million birds) died or were culled, heavily impacting households and the national economy.

In the last decade, the direct cost attributed to zoonoses was estimated at more than $20 billion and indirect cost at more than $200 billion.

Improved prevention and control measures far outweigh the cost of investment in human and animal health services. However, in most cases, zoonotic disease outbreaks have received a reactive response, particularly to large outbreaks, such as the avian influenza. Investments in identifying zoonotic diseases at source could prevent outbreaks or enable rapid response in an event of an outbreak and reduce impact through early detection and control. Investment in human and animal health systems to mitigate pandemic and epidemic risks in low and middle-income countries is estimated to generate high return. Globally an annual investment of $1.8 billion to $4.5 billion in preventive measures would yield $30 billion to $60 billion per year in avoided costs.

ADB has provided technical assistance at the regional and country levels, and has helped strengthen institutional capacity, including support to improve regulations, build capacity, and develop laboratories and other infrastructure to improve food safety.  Projects include enhancing sanitary and phytosanitary measures in the Greater Mekong Subregion, Mongolia, and Turkmenistan; a sustainable livestock farming and product safety demonstration project in the People’s Republic of China; and strengthening food safety standards in agricultural value chains in central and west Asia.

Public Health Is Connected to Animal Health and the Environment

The Food and Agriculture Organization of the United Nations, the World Organization for Animal Health, and the World Health Organization jointly promote the One Health approach to tackle zoonoses. One Health is a collaborative, multisectoral, and transdisciplinary approach as it recognizes the interconnection of humans, animals, and the environment. Governance and coordination mechanisms of the One Health approach promotes coordination as an effective way of addressing crosscutting problems. Collaboration and coordination are adopted at global, regional and national levels to improve prevention and control of zoonotic diseases.

Zoonotic diseases are transboundary in nature. To effectively manage and control diseases, it is important to network and share information with other countries in the region. The notable regional level efforts that largely work under the One Health approach, include the One Health Network South East Asia, One Health Network South Asia, and GREASE Network. They facilitate disease identification, surveillance, and risk assessments; and develop standard methods for prevention and control of zoonoses among member countries.

Here are examples of how countries in the region are taking the One Health approach.

Countries

Activities under the One Health Approach

Bangladesh

The One Health approach was established at the Institute of Epidemiology, Disease Control and Research in 2016. A strategic framework and action plan was developed and provided with funding from the government budget for its activities.

Bhutan

A One Health Secretariat was established in 2017, led by the Ministry of Health and Ministry of Agriculture and Forests in collaboration with the Ministry of Home and Cultural Affairs and the Khesar Gyalpo University.

Indonesia

The Ministry of Human Development and Culture has coordinated One Health functions within Health, Agriculture, Environment and Forestry and Disaster Management agencies since 2017.

Malaysia

The One Health University Network was established in collaboration with the Ministry of Health. This network has drafted the Integrated Surveillance Manual for Antibiotic Resistance, Consumption and Use.

Mongolia

An all-hazard multisectoral coordination mechanism was set up to cover zoonotic diseases, food safety, and effects of climate change on these diseases. The country is building a one-standard system of real-time reporting, risk assessment, and response that is connected to regional and international systems and aligned with the national disaster management system. In 2018, a web-based, real-time events and risk assessment dashboard was introduced, enabling information exchange and rapid decision-making.

Pakistan

A One Health Hub was established at the National Institute of Health in collaboration with the Pakistan Agricultural Research Council and the Global Climate Impact Study Center. One Health System Mapping and Resource Toolkit is used to identify most important zoonotic diseases and assess the capacity to detect and respond to priority diseases.

Viet Nam

The Viet Nam One Health University Network assisted 20 other universities to integrate One Health content and training modules in health programs, including veterinary, animal science, medical, nursing, public health, environmental health.


[1] Nipah virus outbreak was first recognized in Malaysia in 1999, in Bangladesh in 2001, and identified periodically in eastern India. https://www.who.int/news-room/fact-sheets/detail/nipah-virushttps://www.who.int/csr/disease/nipah/en/.

Resources

ADB.2018. Strategy 2030: Achieving a Prosperous, Inclusive, Resilient, and Sustainable Asia and the Pacific. Manila.

Center for Disease Control and Prevention. Saving Lives By Taking A One Health Approach. Fact Sheet.

J.H. Epstein, et al. 2006. Nipah Virus: Impact, Origins, and Causes of Emergence. Current Infectious Disease Reports. February. 8 (1): pp. 59–65.

O.B. Jonas, et al. 2017. Drug Resistant Infections: A Threat to Our Economic Future. Washington, D.C.: World Bank Group.

W Li, et al. Animal Origins of the Severe Acute Respiratory Syndrome Coronavirus: Insight from ACE2-S-Protein Interactions. 2006. Journal of Virology . 80 (9). pp. 4211–4219. Washington, D.C.: American Society for Microbiology. 

World Bank. 2012. People, Pathogens and Our Planet: the Economics of One Health. Washington, DC: World Bank.

World Health Organization (WHO). Nipah Virus Fact Sheet.

WHO. Nipah Virus Infection.

Z. Huang, et al. 2017. HPAI Impacts on Chinese Chicken Meat Supply and Demand. World's Poultry Science Journal, 73 (3): pp. 543–558. Beekbergen: World's Poultry Science Association.

 

Ask the Experts

  • Samjhana Shrestha
    Senior Economist, Agriculture, Sustainable Development and Climate Change Department, Asian Development Bank

    Samjhana Shrestha specializes in the use of digital solutions and food safety to improve food security and strengthen agricultural value chains. She has over 20 years of experience in international development. Prior to ADB, she worked in various capacities at national, international, and civil society organizations.  She has two post-graduate degrees in Agriculture Economics and Economics from the University of New England, Australia.

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  • Asian Development Bank (ADB)

    The Asian Development Bank is committed to achieving a prosperous, inclusive, resilient, and sustainable Asia and the Pacific, while sustaining its efforts to eradicate extreme poverty. Established in 1966, it is owned by 68 members—49 from the region. Its main instruments for helping its developing member countries are policy dialogue, loans, equity investments, guarantees, grants, and technical assistance.

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   Health
   Last updated: August 2019



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