One Health in a globalized world: challenges and responses to zoonotic threats

ABSTRACT

This article explores the relationship between zoonotic outbreaks and the interconnected nature of globalization through the lens of the One Health framework. It argues that global ecological changes driven by climate changes, deforestation, intensified agriculture, wildlife trade, and urban expansion have significantly elevated the risk of zoonotic disease transmission. It emphasizes how globalization has intensified some of the factors that contribute to the emergence of zoonotic outbreaks, and has also facilitated the spread of infectious diseases. Drawing on recent examples, such as the emergence of H1N1, COVID-19 and Nipah virus outbreaks, the article emphasizes the need for robust, interdisciplinary collaboration among human, animal, and environmental health sectors. The article advocates for a comprehensive global strategy rooted in the One Health approach to mitigate future zoonotic threats. It argues that this approach is based on an ethical principle of solidarity, which refers to the enacted commitment to support others based on the recognition of shared vulnerabilities or similarities. This principle is essential for collective responses to global challenges like zoonotic diseases. The One Health approach requires reinvesting in multilateral governance, enhancing wildlife and livestock surveillance, and addressing socio-environmental drivers of disease emergence, thereby promoting planetary health and global biosecurity. However, it also highlights the vulnerabilities created by nationalistic and populist policies, based on a distrust of multilateral organizations and international cooperation, and that have underfunded global health institutions, particularly affecting low-resource regions where early detection systems are lacking.

Introduction

For the last few decades there has been a sharp rise in the number of infectious disease outbreaks impacting people worldwide (Smith et al., 2014). Data indicates that the number of new infectious disease outbreaks per year has more than tripled since 1980 (Gruber, 2021). In Africa, for example, there was a 63% rise in zoonotic outbreaks between 2012 and 2022 compared to the previous decade (WHO, 2022). This upward trend underscores the growing global concern regarding zoonotic diseases.

In a study published in 2005, Mark Woolhouse and Sonya Gowtage-Sequeria (2005) examined 1,407 known human pathogens and found that 58% were of zoonotic origin. Of all the species analyzed, 177 were classified as emerging or reemerging pathogens – and strikingly, three-quarters of these emerging pathogens were zoonotic. Whenever a new and unusual disease appears, it is most likely to be a zoonosis. A few years later, Woolhouse and some other colleagues (2012) stated that every year, scientists discover three to four new virus species capable of infecting humans. Pathogens that leap from animals to humans are twice as likely to drive emerging diseases compared to those with no animal origin (Otte & Pica-Ciamarra, 2021).

In this paper I shall draw attention to several environmental, social and other factors that contribute to the emergence and spread of zoonotic diseases. These factors have been intensified by the process of globalization that we have gone through during the same period of time, that is, since the 1980s. I emphasize several factors: habitat destruction, wildlife trade and animal markets, intensive farming practices, climate change, and global travel. I shall argue that the One Health approach – which recognizes that human, animal and environmental health are interconnected – helps us in facing the causes of these zoonotic diseases. I argue that this approach is based on an ethical principle of solidarity, which demands that we support others based on the recognition of shared similarities and vulnerabilities. It involves takeng on social, financial, or moral costs to assist those in need, not out of charity, but from a sense of mutual interdependence. This principle is essential for collective responses to global challenges like zoonotic diseases. Finally, in order to put into practice this approach, four strategies should be implemented: integrated surveillance, collaborative research, policy and governance, and education and awareness. However, I argue that the vulnerabilities created by nationalistic and populist policies, based on a distrust of multilateral organizations and international cooperation, have underfunded and even dismantled global health institutions, and threaten to weaken the One Health approach.

Factors that contribute to the emergence and spread of zoonotic diseases

Emerging zoonotic outbreaks have become a growing global concern, with significant implications for public health. Over the past few decades, the frequency of these outbreaks has risen markedly. After analyzing the amount of these events in the last sixty years, Amanda Meadows and her colleagues (2023) claim that the number of spillover events of zoonotic origin has been increasing by 4.98% annually, and the number of reported deaths related to these events 8.7%. This trend highlights the urgent need to understand the factors behind zoonotic spillovers and develop strategies to mitigate their impact. In this section I shall enumerate some of the main factors that contribute to the emergence and spread of zoonotic diseases – although this list is not meant to be exhaustive.

Habitat destruction and environmental changes

Deforestation, urbanization, and agricultural expansion lead to habitat loss, which brings wildlife into closer contact with humans, raise the likelihood of disease spillover events from animals to humans. For instance, vast areas of tropical rainforest have been cleared to establish palm oil plantations, particularly in Guinea and Liberia, where there was an Ebola outbreak in 2014 (Urey, 2015; Wallace et al., 2014); but also in Sumatra and Borneo (Jong, 2023), where this deforestation has displaced wildlife such as orangutans and bats, increasing interactions with human populations and creating opportunities for zoonotic disease transmission.

Something similar has happened with urbanization: urban sprawl in and around Jakarta, for example, has consumed wetlands and forested areas, leading to habitat fragmentation; as wildlife is pushed into smaller, isolated patches, contact between animals and urban populations has increased (Adnyana et al., 2023; Svensson et al., 2020). The same can be said about Vietnam: the rapid urbanization of Ho Chi Minh City has encroached on forested regions, bringing humans into closer proximity to wildlife such as bats, known carriers of zoonotic pathogens like coronaviruses (Pham-Thanh et al., 2022; Spencer et al., 2020).

Destruction of wetlands and mangroves has also increased due to the construction of touristic infrastructure (resorts, airports, piers, golf courses, etc.), which implies the destruction of natural habitats, the displacement of wildlife, and again, more opportunities for a closer interaction with human populations (Sustainable Travel International, 2024). It also implies less protection from storms, as these wetlands mitigate the destructive effects of cyclones, hurricanes and typhoons – which usually bring about damages to urban areas that bring up the conditions of appearance of zoonotic outbreaks, such as Leptospirosis (Jones et al., 2024).

The conversion of forests into agricultural land through slash-and-burn practices – which consist in cutting down trees and burning vegetation to create a field and fertilize the soil for growing crops – has led to widespread habitat loss. This method of clearing land is common in upland regions in countries like Laos, Cambodia and Vietnam (Mermoz et al., 2021; Sim et al., 2023), where close contact with wildlife during land use increases spillover risks.

The growth of rubber plantations in Southeast Asian countries (such as Cambodia, Indonesia, Myanmar, Thailand and Vietnam) has transformed biodiverse forests into monocultures, drastically reducing wildlife habitats (Shah et al., 2019). The loss of natural buffers between animals and humans elevates the likelihood of pathogen transmission. In fact, Hiral Shah and his colleagues (2017) have argued that people who live or work in agricultural land in that region are on average 1.74 times as likely to be infected with a pathogen than those unexposed.

Wildlife trade and animal markets

One of the leading hypotheses about the origin of the COVID-19 pandemic is its potential link to wildlife trade, specifically associated with Wuhan’s Huanan Seafood Market – commonly referred to as a wet market (Crits-Christoph et al., 2024). This hypothesis suggests that the virus likely emerged from animals sold or present at the market, where diverse species, including wildlife, were kept in close quarters under conditions conducive to cross-species transmission. Wet markets often feature live animals, including wildlife, housed in crowded environments that facilitate the exchange of pathogens between species and humans – for instance, animals confined to cages experience immune system depression due to chronic stress. Such conditions can act as “mixing vessels,” enabling viruses to jump from their original animal hosts to humans. The initial outbreak in Wuhan was traced to clusters of cases linked to the market, though the precise animal source remains unidentified. Studies have pointed to bats as the probable original reservoir of SARS-CoV-2 (Temmam et al., 2022), with an intermediate host – potentially pangolins or another species – transmitting the virus to humans (Gupta et al., 2022).

The report Animal Markets and Zoonotic Disease Risk (Brooks McCormick Jr Animal Law & Policy Program, 2023) highlights the significant zoonotic disease risks posed by animal industries and markets. It presents one of the most comprehensive reviews to date on how various sectors of animal use – including wet markets, wildlife trade, but also factory farms and fur farms – contribute to the emergence and spread of zoonotic pathogens.

Wildlife trade, encompassing both legal and illegal activities, is a critical and often overlooked driver of zoonotic disease emergence. This trade involves the capture, transport, sale, and consumption of wild animals, many of which are removed from their natural habitats and brought into close contact with humans and domesticated species. Such interactions break natural ecological barriers and facilitate the transmission of novel pathogens across species – in a process known as spillover.

While definitive proof of the wildlife trade’s role in the COVID-19 pandemic’s origins remains elusive, this hypothesis stresses the significant risks posed by such practices. It has fueled calls for stricter regulations on wildlife trade and improved surveillance of zoonotic diseases at the human-animal interaction to prevent future outbreaks (Ortiz-Millán, 2020). The legal and illegal wildlife trade, including live animal markets, can facilitate the spread of zoonotic diseases. Close contact between various animal species in crowded conditions creates a breeding ground for pathogens that can jump to humans.

Intensive farming practices

Modern animal agriculture – particularly industrial-scale, high-density farming operations – creates ideal conditions for pathogens to evolve, spread, and potentially jump from animals to humans. These settings confine large numbers of genetically similar animals in small spaces; facilitate rapid transmission of infectious agents; often involve high use of antibiotics, contributing to antimicrobial resistance (Martin et al., 2015; Wallace, 2016, p. 122, 277ff; Ortiz-Millán, 2025b); and frequently lack transparency and health monitoring in many parts of the world.

When animal immune systems are stressed due to overcrowding or poor living conditions, they become more susceptible to infections, and viral mutations can accumulate rapidly. These factors increase the risk of zoonotic spillover, especially when humans (farmworkers, local communities) come into direct or indirect contact with animals or their waste. Industrial farms have repeatedly created conditions favorable to zoonotic disease emergence (Wallace, 2016).

For example, in 1998–1999, the Nipah virus emerged in pig farms, in Malaysia, where fruit bats (Pteropus spp.) – natural reservoirs of the virus – were attracted to fruit trees planted near pigpens. The bats dropped partially eaten fruit contaminated with virus-laden saliva, which pigs consumed. The virus spread among pigs and subsequently infected farm workers, causing severe illness and death. Over a million pigs were culled to control the outbreak (Quammen, 2012: chap. 1; MacKenzie & Prowse, 2009).

In another case, the H1N1 influenza pandemic of 2009 (sometimes also called “swine flu”) is widely believed to have originated from a genetic reassortment of influenza viruses in pigs. One of the early clusters of cases occurred in La Gloria, in the state of Veracruz, Mexico, near a large industrial pig farming operation owned by Granjas Carroll, a subsidiary of Smithfield Foods, a transnational pork producer. Local residents had long complained about air and water pollution from the pig farms, and some reported respiratory illnesses months before the outbreak was formally identified (Mena et al., 2016; Wallace, 2016). Although conclusive epidemiological linkage to the farm remains debated, the case illustrates the potential risks posed by large-scale confined animal feeding operations (CAFOs). It is estimated that the H1N1 flu pandemic caused about 284,000 excess deaths, according to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) from the United States (Janukavicius, 2014).

While wildlife trade and wet markets are often considered risk factors, intensive livestock farming – especially in high-density, poorly regulated settings – may pose an equally or greater threat in terms of scale and frequency of occurrences. A serious reevaluation of global food systems, including reforms in animal agriculture, use of antibiotics as growth promoters, surveillance, and land use policy, is essential to reduce the risk of future pandemics.

Climate change

Climate change is not just an environmental issue – it is increasingly recognized as a public health threat, particularly in its role in driving emerging infectious diseases. As global temperatures rise and weather patterns shift, the ecosystems that support both wildlife and disease vectors (such as mosquitoes, ticks, and rodents) are disrupted. This leads to (a) Geographic expansion of vectors: warmer climates allow disease-carrying insects to thrive in areas that were previously less warm or actually cold, bringing diseases into new regions and exposing naïve populations. (b) Altered migration and reproduction patterns: changes in seasonal cycles affect the behavior of both hosts and vectors, potentially increasing the period during which disease transmission can occur. (c) Habitat disruption: climate-induced habitat loss may push wild animals closer to human settlements, increasing opportunities for zoonotic spillovers. (d) Extreme weather events: floods, droughts, and storms can displace both animals and people, heightening human-animal interactions in unstable, crowded conditions.

A good example of how climate change influences the emergence of zoonotic diseases is the case of Lyme disease through the pathogen vector, the tick Ixodes scapularis. As winters become milder and the frost-free season extends, ticks that carry Lyme disease are expanding their range northward into Canada and higher altitudes in the U.S. Warmer temperatures improve tick survival rates and extend the season during which they are active. This has led to increased incidence of Lyme disease in regions that historically had little or no risk, directly linking vector expansion to climate change (Brownstein et al., 2005; Quammen, 2012).

Another example is the case of Nipah in Southeast Asia. Combined with the vicinity of fruit bats and pigs already mentioned, climate change has also put pressure on bats in the emergence of the Nipah virus. Fruit bats, the natural reservoir of the virus, are highly sensitive to changes in climate. In Bangladesh and India, deforestation and temperature increases have pushed these bats to feed closer to human dwellings. During periods of food scarcity – often exacerbated by drought or habitat loss linked to climate shifts – bats are more likely to forage in date palm trees, contaminating the sap with saliva or urine. People who consume raw sap are then exposed to the virus. These changing environmental patterns increase the risk of spillover events. There is no vaccine or curative treatment for people who get infected with the Nipah virus, and in past outbreaks fatality rates have been as high as 94% (Branda et al., 2025; Daszak et al., 2012; Quammen, 2012).

Climate change acts as a risk multiplier for zoonotic disease emergence. By transforming landscapes and species distributions, it alters the ecology of disease in ways that are often difficult to predict but increasingly observable. Effective public health strategies must now integrate climate forecasting with zoonotic disease surveillance to anticipate and mitigate future outbreaks.

Global travel

Sonia Shah’s book Pandemic (2017) offers a compelling exploration of how globalization and human mobility have accelerated the emergence and spread of infectious diseases. She frames pandemics not as isolated medical anomalies, but as social and ecological phenomena deeply shaped by trade, travel, urbanization, and human encroachment into ecosystems. Shah argues that modern pandemics are not just biological accidents, but are products of human systems: the expansion of global commerce, including the wildlife trade and industrial agriculture, creates new opportunities for pathogen emergence. Meanwhile, hyper-connectivity through tourism, labor migration, and cargo shipping enables microbes to cross borders faster than public health systems can respond. She notes that we have built a world where microbes can travel faster than information or medical infrastructure, and where marginalized populations are often the most exposed to early waves of infection.

A particularly illuminating example she discusses is the Severe Acute Respiratory Syndrome (SARS) outbreak of 2002–2003. The SARS coronavirus likely originated in civet cats sold in Chinese wet markets and then jumped to humans. From a localized outbreak in Guangdong, China, it spread rapidly to 29 countries within months, thanks largely to international air travel. One infected physician who stayed in a Hong Kong hotel passed the virus to multiple other guests, who then returned to Canada, Singapore, and Vietnam – each sparking outbreaks. Shah analyzes how dense air travel networks and urban connectivity allowed SARS to spread more quickly than earlier diseases like cholera or plague.

Globalization – through international travel, trade, and urbanization – has transformed the landscape of disease emergence and transmission. Shah urges us to rethink how our economic and infrastructural systems contribute to pandemic risk. Her work is especially prescient in light of COVID-19, which followed a similar trajectory: likely zoonotic origins, enabled by wildlife trade, followed by explosive global spread through air travel. Her analysis accentuates the importance of anticipating pandemics as systemic phenomena, not simply biological threats.

How globalization has intensified the occurrence of zoonotic outbreaks

Globalization is the process by which people, goods, information, and ideas move increasingly across borders, creating greater economic, cultural, and political interconnectedness and interdependence among countries worldwide (MacGillivray, 2006; Steger, 2013). The history of globalization may be traced back to the origins of civilization, and with this process came the spreading of diseases: ever since people started migrating to different places in the world, they also began getting and spreading new diseases. However, the form of globalization that started in the 1980s has meant a deepening web of interdependence and connectivity among individuals, corporations, and nations across the globe. Events unfolding in one part of the world are increasingly influenced by developments happening simultaneously in distant regions. However, this heightened interconnectedness also brings significant challenges and vulnerabilities: globalization has exponentially intensified the factors that contribute to zoonotic outbreaks (Ortiz-Millán, 2022).

A landmark study by Jones and collaborators (2008) found that between 1940 and 2004, over 60% of emerging infectious diseases was zoonotic, and their incidence increased significantly after 1980. This timeline aligns with the rapid expansion of globalization processes, including global trade, deforestation, and urban sprawl.

Global demand for agricultural and industrial expansion – largely driven by globalization – has led to widespread deforestation and the rapid expansion of the geographic extent of cities. This has brought humans into closer contact with wildlife, increasing the risk of spillover events. Deforestation for palm oil plantations and urban encroachment in Southeast Asia are prime examples.

Globalization has also fueled both legal and illegal wildlife trade. The legal global wildlife trade has increased by over 2000% since 1980, creating a booming market where zoonotic pathogens can easily jump species barriers. The estimate value of illegal wildlife trade globally is around $7–23 billion annually, equivalent to nearly 25% of the value of the legal market (Eurogroup for Animals, 2020). United Nations estimates that some 7,000 species are illegally trafficked, contributing to the increase spread of zoonotic diseases, loss of biodiversity and damage of ecosystems (Lowery, 2023). Wildlife markets like the Huanan Seafood Market in Wuhan are emblematic of how global trade networks facilitate zoonotic risk.

The globalization of food systems has catalyzed a dramatic expansion in industrial-scale animal farming, elevating the risk of zoonotic disease emergence. CAFOs, now prevalent across the globe, are environments where large numbers of livestock are kept in densely packed conditions to maximize meat and dairy production efficiency. This setup facilitates the rapid transmission and mutation of pathogens due to close animal contact, high stress levels, immune system depression and routine antibiotic use. The 2009 H1N1 influenza pandemic, which emerged in pig farming operations in Mexico, exemplifies how CAFOs can serve as breeding grounds for novel viruses with pandemic potential. Global demand for inexpensive animal protein, driven by rising middle-class consumption in developing countries and integrated international supply chains, has led to a homogenization of farming practices that neglect local ecological safeguards. Furthermore, the widespread prophylactic use of antibiotics, but also used as growth promoters, in these settings contributes to antimicrobial resistance, making zoonotic infections harder to treat once they spill over into human populations (Martin et al., 2015). Studies have shown that such intensive systems not only heighten the risk of disease but also amplify their potential for global spread via trade networks. Addressing these vulnerabilities requires integrating the One Health approach into global agricultural and trade policies.

Globalized industrial activity (including industrial agriculture) has significantly accelerated climate change, which in turn is reshaping ecosystems and facilitating the spread of zoonotic diseases. Rising global temperatures, shifting precipitation patterns, and increased frequency of extreme weather events (such as hurricanes and droughts) are expanding the geographic range of disease vectors such as mosquitoes and ticks. In this way, as mentioned, Lyme disease, once confined largely to northeastern North America, is now being reported further north and west due to warming climates that allow ticks to survive in previously inhospitable regions. Similarly, West Nile virus, transmitted by mosquitoes, has spread into parts of Europe and North America where it was previously rare (WHO, 2017). These changes are not merely ecological, but deeply tied to globalization-driven phenomena such as deforestation, fossil fuel consumption, and urbanization. As global industries push into natural habitats, they disturb ecological balances and expose humans to novel pathogens. Addressing these risks requires coordinated global action focused on environmental sustainability and public health integration.

Travel and transportation have also become significantly faster and more accessible due to globalization. According to data from the International Air Transport Association (IATA), global air passenger numbers have increased from about 310 million in 1970 to over 4.5 billion in 2019 (ICAO, 2019). This ease of movement means that localized zoonotic outbreaks can become global pandemics within days – as seen with SARS in 2003 and COVID-19 in 2020.

Globalization’s interconnectivity has not only facilitated the rapid spread of zoonotic diseases but also entrenched systemic vulnerabilities. These include global inequities in wealth and healthcare access, which amplify the impact of pandemics on marginalized populations. Thus, globalization has exacerbated inequalities within countries (Stiglitz, 2012), often worsening sanitary conditions in urban slums and rural areas. Poor sanitation and improper disposal of animal and human waste can attract animals that carry pathogens, such as rodents and insects, increasing the risk of zoonotic disease transmission to humans.

To sum up, globalization has not only intensified the known causes of zoonotic outbreaks but also made the world more susceptible to their rapid spread and impact. Addressing these challenges requires systemic change through global cooperation, sustainable development, and integrative health policies. It also requires a more comprehensive perspective that takes into account the interconnectivity of human health with animal and environmental health, such as the one proposed by the One Health perspective.

In addressing the global challenges posed by zoonotic outbreaks, acting on ethical principles – particularly the principle of solidarity – is not only morally appropriate, but also practically essential. As articulated by Barbara Prainsack and Alena Buyx, solidarity signifies “shared practices reflecting a collective commitment to carry ‘costs’ (financial, social, emotional, or otherwise) to assist others” (Prainsack & Buyx, 2011, 46, their emphasis), others with whom we recognize sameness or similarity in some relevant respect. This understanding implies that solidarity is not merely a sentiment, but a practice grounded in mutual recognition and shared vulnerabilities. In the context of One Health, which stresses the interdependence of human, animal, and environmental health, solidarity requires acknowledging that the health threats affecting one population – be it a community in Southeast Asia or a wildlife species in Mexico – are ultimately shared by all. Globalization has increased human mobility, intensified trade in animals and animal products, and expanded land-use change, all of which heighten the risk of zoonotic spillovers. Responding to such risks, therefore, demands transnational solidarity and cooperation that transcends narrow national interests. Solidarity in this setting obligates wealthier nations and global institutions to support surveillance, health infrastructure, and early warning systems in lower-income regions where such outbreaks often begin. It also justifies shared investments in vaccine development, coordinated policy responses, and fair distribution of health technologies. In short, solidarity offers both the ethical justification and the framework for the kind of collective action required to prevent and mitigate zoonotic pandemics in an interconnected world.

One Health and its vulnerabilities

The One Health approach recognizes the interconnectedness of human, animal, and environmental health. It operates under the understanding that the health of people is closely linked to the health of animals and the environment they share. It also operates on a principle of solidarity, but here solidarity is not limited to human communities, but extends across species and, why not, ecosystems. Solidarity means to assist others – whether humans, animals, or ecosystems – when we recognize relevant similarities, interdependencies and vulnerabilities. In a globalized world where zoonotic diseases arise from interactions between human activity and animal habitats, the principle of solidarity urges us to act not out of charity, but from shared vulnerability and mutual interest. By acknowledging our biological and ecological connectedness, One Health reframes public health as a collective endeavor that bridges species boundaries, morally demanding cooperative efforts in prevention, surveillance, and response.

The One Health approach is particularly crucial in the prevention and control of zoonotic diseases in a globalized world. It must operate on a global scale because the forces that drive zoonotic disease emergence and spread are themselves globalized. Over the past decades, globalization has interconnected nations through trade, travel, agriculture, and communication, facilitating not only economic growth but also the rapid movement of people, animals, and pathogens across borders. As a result, a zoonotic outbreak in one region can quickly become a global threat, as seen with SARS, H1N1 influenza, and most notably, COVID-19.

Land-use changes driven by global commodity demands – such as palm oil and meat – lead to deforestation and habitat disruption, increasing human-wildlife contact. Similarly, global food systems promote intensive animal farming, a known risk factor for disease emergence. Moreover, international wildlife trade, both legal and illegal, has expanded dramatically, creating global markets where pathogens can jump species barriers. These trends are not confined to national jurisdictions, and their consequences are felt globally. Therefore, the One Health response must transcend borders through coordinated policies, data sharing, and joint surveillance systems. International institutions like the WHO, World Organization for Animal Health (WOAH), and the Food and Agriculture Organization (FAO) must collaborate with national governments, NGOs, and local communities to implement unified health responses. Only a globally integrated approach can effectively mitigate the risks posed by a highly interconnected world where zoonotic spillovers are not just local incidents but potential global crises.

There are some key elements of the One Health approach that should be taken into account to successfully implement it, which can be divided into four categories: integrated surveillance, collaborative research, policy and governance and education and awareness.

Integrated surveillance

Integrated surveillance is a cornerstone of the One Health approach, enabling the early detection and rapid response to emerging zoonotic threats. This integrated system entails the simultaneous monitoring of health indicators across human populations, domestic livestock, and wildlife, as well as environmental changes that may facilitate disease transmission. However, in many low-resource regions – often those at the frontlines of zoonotic emergence – surveillance systems are either weak or non-existent. Limited disease surveillance in these areas can significantly delay the identification of outbreaks. For example, a novel virus circulating in wildlife or livestock may go undetected until it spills over into humans and causes severe illness, by which time it may already have spread extensively. The Ebola outbreak in West Africa exemplifies how limited disease surveillance, compounded by mistrust in government systems and lack of early community engagement, allowed the virus to spread undetected for weeks, resulting in over 11,000 deaths and global panic (Bird & Mazet, 2018).

By decentralizing surveillance systems and incorporating local actors like traditional healers and wildlife experts, the One Health approach becomes more responsive and inclusive, addressing the complex sociocultural and ecological interfaces where zoonotic spillovers occur. Without these decentralized and integrated systems, emerging diseases are likely to go unnoticed until widespread transmission occurs, highlighting the critical need for sustained investment and global cooperation in One Health infrastructure.

The absence of early warning systems means that vital time is lost in implementing containment measures, increasing the risk of regional or global transmission. Moreover, data gaps caused by under-reporting, lack of diagnostic tools, and insufficient cross-sectoral coordination hinder timely decision-making. An integrated surveillance network, supported by robust infrastructure and international collaboration, is therefore essential. By improving disease monitoring across species and ecosystems – especially in hotspots of zoonotic risk – we can enable more proactive health responses and prevent localized outbreaks from escalating into pandemics.

The PREDICT project (which initiated in 2009 and ended in 2020), part of the United States Agency for International Development (USAID) Emerging Pandemic Threats Program, showed that capacity-building at local levels – through training, community engagement, and integration of laboratory diagnostics – can drastically enhance early detection and response to zoonotic threats (One Health Institute, 2020; Sharan et al., 2023). Once the PREDICT ended, a successor project, Strategies to Prevent Spillover (STOP Spillover), was announced in September 2020, with a similar mission to anticipate and address threats from emerging zoonotic diseases and it’s programmed to continue until September 2025 (USAID, 2020). However, the Trump administration eliminated over 90% of USAID’s foreign aid contracts and a massive reduction in overall U.S. assistance, which involved canceling thousands of contracts and grants, including 86% of all USAID awards in some reports (Knickmeyer et al., 2025). While STOP Spillover is a cooperative agreement, it would fall under the umbrella of USAID’s foreign assistance and therefore be subject to these sweeping cuts.

The budget cuts to USAID – which basically mean the dismantling of the agency – ordered by the Trump administration are poised to significantly undermine global pandemic surveillance and response capabilities. With funding slashed, the ability of USAID (or what remains of it) to maintain surveillance networks, support laboratory diagnostics, and engage with local communities will be diminished. Experts warn this will create blind spots in regions that are often the epicenters of zoonotic spillovers. These cuts have led to the scaling back or closure of numerous programs that were crucial in detecting and containing disease outbreaks, particularly in low-income countries (such as Kenya, Congo, Uganda, Nigeria and other African nations) where health infrastructure is limited (Mandavilli, 2025). (USAID’s agricultural programs are also threatened, something which would undermine food security and rural livelihoods; and on top of that, Trump’s tariffs are going to have a very negative impact on their economies (Usman, 2025).) The reduction in funding also jeopardizes early warning systems, crucial for rapid containment before outbreaks escalate. Without these mechanisms, the world is at increased risk of delayed responses, broader transmission, and higher economic and human costs. The cuts not only reduce the U.S. government’s influence in global health governance but also weaken collective global preparedness just as climate change and globalization continue to increase zoonotic threats.

Collaborative research

Collaborative research is a foundational pillar of the One Health approach, aimed at bridging disciplinary gaps to better understand and mitigate the dynamics of zoonotic diseases. By fostering cooperation among experts in human medicine, veterinary science, environmental health, epidemiology, and bioethics, collaborative research enhances the capacity to detect, monitor, and respond to health threats at the animal-human-environment interface. This synergy is crucial for identifying emerging pathogens, understanding their transmission pathways, and designing interventions that are both scientifically sound and culturally appropriate.

Once again, an illustrative example is the PREDICT program, which exemplified successful interdisciplinary collaboration by linking local and international researchers to study wildlife pathogens and their potential for human transmission. PREDICT teams operated across more than 30 countries, collecting more than 164,000 of biological samples and discovering 949 new viruses, including strains similar to Ebola and coronaviruses (One Health Institute, 2020; Bird & Mazet, 2018). This project worked closely with local health workers, veterinarians, and ecologists, building capacity and establishing early warning systems. However, this kind of programs is likely to be downscaled, if not disappeared, due to the Trump administration’s budget cuts to USAID. This will mean the reduction of global preparedness. Without such collaborative initiatives, the world risks losing critical insights into zoonotic threats before they manifest as pandemics, weakening the global response capacity at a time when interconnected threats are intensifying.

Policy and governance

Policy and governance play a crucial role in operationalizing the One Health approach, ensuring that strategies to address zoonotic threats are not only interdisciplinary but also institutionally coordinated and sustainably funded. Effective governance requires alignment among health, agricultural, environmental, and wildlife agencies, both domestically and internationally. This coordination is essential to confront complex issues like antimicrobial resistance, habitat destruction, and climate change, which transcend sectoral boundaries and national borders.

Robust policy frameworks that institutionalize One Health collaborations across ministries and borders are vital. They enable proactive risk assessment, transparent data sharing, and cohesive responses to zoonotic threats – essentials for pandemic prevention in a globalized and more interconnected world. In contrast, fragmented governance can exacerbate risks. The lack of a unified global policy on wildlife trade has allowed, for instance, for continued operations of high-risk markets. According to Brian Bird and Jonna Mazet (2018), poor interagency coordination during the early stages of the Ebola outbreak in West Africa delayed crucial containment measures, illustrating the critical need for integrated governance structures.

However, in recent years, illiberal forms of populism have fostered nationalistic policies and a growing distrust in multilateral and supranational organizations such as the WHO (Ortiz-Millán, 2025a), which are essential for the effective implementation of the One Health approach. These institutions play a crucial role in coordinating global responses to health threats that do not respect national borders. Nevertheless, governments such as that of Donald Trump in the U.S. have announced the suspension of funding to the WHO, and recently, Argentine President Javier Milei has followed the same course (Nicas, 2025). These decisions weaken the mechanisms of international cooperation necessary to face global public health challenges and undermine the world’s ability to prevent and respond effectively to future zoonotic pandemics.

Education and awareness

Education and awareness are essential components of the One Health framework, as they foster the cross-disciplinary understanding and public engagement necessary to prevent and control zoonotic diseases (Deem et al., 2019). By educating healthcare workers, veterinarians, ecologists, and policymakers in integrated health approaches, One Health creates a shared language and understanding that enhances collaboration. Furthermore, public awareness campaigns help communities recognize the risks associated with wildlife interactions, improper animal handling, and environmental degradation.

An example of the impact of education comes, once again, from the Ebola outbreak in West Africa (2014–2016), where community resistance to public health measures was a significant challenge. Misunderstandings about disease transmission led to violence against health workers and concealment of infected individuals. Effective community engagement through local leaders and education significantly improved cooperation and disease reporting, eventually helping to contain the outbreak (Bird & Mazet, 2018).

The PREDICT program emphasized the education and awareness components by training over 6,800 individuals in outbreak-prone regions, ranging from wildlife rangers to laboratory technicians (One Health Institute, 2020). This training improved local capacity to detect and respond to disease threats, as well as to educate their communities on best practices. These efforts demonstrate that sustained investment in One Health education can build resilient systems capable of addressing emerging health challenges before they escalate into global crises.

Conclusions

The increasing frequency and global impact of zoonotic outbreaks over the past five decades accentuate the urgent need for a comprehensive and integrative health approach. The emergence of diseases like HIV/AIDS, Ebola, H1N1, Zika, Chikungunya, SARS, and COVID-19, among many others, is closely linked to anthropogenic factors such as deforestation, intensive animal farming, wildlife trade, and climate change – all of which have been intensified by globalization. These interconnected drivers highlight the importance of adopting the One Health approach, which recognizes the intrinsic links between human, animal, and environmental health, and plans a global response to these threats.

Traditional, human-centered models of public health are no longer adequate in addressing the complex, systemic nature of zoonotic diseases in today’s globalized world. Historically, public health strategies have primarily focused on human disease prevention and treatment, often isolating human health from the broader ecological and animal contexts in which diseases emerge. However, this siloed approach fails to capture the full picture of zoonotic spillovers, which typically originate at the intersection of human, animal, and environmental systems. Emerging infectious diseases are increasingly linked to environmental degradation, intensive livestock farming, biodiversity loss, and global trade – all processes that involve interactions beyond the human realm. For instance, deforestation not only displaces wildlife but also brings animals carrying novel pathogens into closer contact with human populations. Similarly, industrial farming creates dense animal populations that can act as incubators for disease transmission. Ignoring these ecological and animal health dimensions results in blind spots in disease surveillance and outbreak prevention.

Therefore, the One Health framework proposes a necessary shift from an anthropocentric paradigm to a holistic, integrative model, based on a principle of solidarity with other human beings, with animals as well as ecosystems. It acknowledges that human health cannot be protected in isolation and must instead be considered as part of a shared ecosystem. This shift is essential for effective prevention, early detection, and response to the multifactorial threats posed by zoonotic diseases.

The One Health approach calls for ethical responsibility and global solidarity, stressing that effective pandemic prevention must address structural injustices and environmental degradation. However, we must be attentive to the vulnerabilities created by nationalistic policies, based on a distrust of multilateral organizations and international cooperation, and that have underfunded global health institutions, particularly affecting low-resource regions where early detection systems are lacking. It is necessary to denounce these policies and defend these institutions if we want the One Health approach to be successful. This framework is not just a scientific model, but also a necessary paradigm shift to safeguard planetary health in a progressively more interconnected world. Without these collaborative efforts proposed by the One Health approach – efforts threatened by populist and nationalistic governments – the world may be deprived of essential knowledge about zoonotic outbreaks before they escalate into pandemics, thereby undermining global preparedness at a time when interconnected risks are becoming increasingly severe.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Use of generative AI

The author acknowledges the use of Chat GPT 4o for brainstorming, for getting some examples, formatting the references, and also for revising and improving his writing style in English.