In a recent review published in a magazine PLoS pathogen, The authors’ group prioritized primary prevention of pathogen spills, integrated a One Health approach, and leveraged global efforts and investments for a comprehensive strategy to avoid future pandemics at their source.
Opinion: Preventing zoonotic disease spillover: From relying on response to reducing risk at the source. Image credit: Maximillian Cabinet / Shutterstock
The global health crisis caused by the coronavirus disease 2019 (COVID-19) pandemic has intensified discussions about improving pandemic preparedness. The main cause of emerging infectious diseases is the spread of zoonotic diseases from animals to humans, influenced by factors such as deforestation and agricultural relocation. Despite the clear economic benefits of prevention, many strategies, such as the World Bank Pandemic Fund, focus primarily on response rather than active prevention. The ‘prevention paradox’ can influence such attitudes, overlooking the significant economic and social benefits that can be gained from pre-emptive action. Notably, while significant investments are being made in areas such as counter-terrorism and flood management to reduce potential risks, there is an equal focus on pandemic prevention. Further research is needed to identify the optimal resource allocation for proactively preventing pandemics, and to move from costly reactive strategies to more sustainable preventive strategies. It is necessary to emphasize reducing the spread of infectious diseases.
Understanding “spread prevention”
Contextualizing “prevention” in medical settings
It is important to clearly define spillover prevention in relation to outbreaks, disease pervasiveness, epidemics, and pandemics to ensure actions and resources are directed appropriately. Currently, the interpretation of “prevention” varies depending on the situation. For example, in public health, it may mean avoiding a human disease altogether (primary prevention) or stopping a local disease outbreak from escalating into a more serious crisis (secondary prevention). there is. Secondary prevention includes methods such as vaccination, early detection, health system strengthening, health advocacy, pharmacotherapy, behavior modification, and hygiene. However, to reduce misunderstanding, secondary prevention may be better labeled as ‘containment of infection’ to better convey its purpose as opposed to spillover prevention.
For the purposes of this discussion, “preventing spillover” refers to preventing the first critical step of stopping a pathogen from moving from animals to humans. Although we primarily focus here on human pandemic prevention, human actions that facilitate spillover between different species (such as the wildlife trade) can also wreak havoc on wildlife and livestock populations. It is important to be aware that this can lead to
Preventing the spread of zoonotic diseases: From relying on response to reducing risk at the source
One Health Approach to Addressing Ripple Effects
A holistic approach to combating spillover effects can be established by addressing spillover factors through One Health strategies that center on the human-animal-environment connection. This strategy aims to minimize the risk of zoonotic pathogens to humans and may incorporate interventions such as vaccination. To clarify priorities for preventing future outbreaks that could lead to pandemics, we propose a definition of prevention that focuses on avoiding zoonotic disease spillover. This includes all precursor events that influence pathogen spillover, while subsequent activities are classified as unpreparedness and response actions.
Distinguishing between primary and secondary prevention
Preventing the proliferation of pathogens in humans (known as secondary prevention) clearly involves containment strategies that are activated after the pathogen has been introduced into humans. These strategies have potential applications in a variety of fields, including public health, animal health, and environmental management.
Scope of spill prevention
Basics of spillover occurrence
The basis of pathogen spillover from natural sources lies in the direct or indirect contact between humans and pathogens, usually through infected hosts or the environment. Importantly, animals and biodiversity are inherently risk-free. Rather, it is human actions that result in dangerous interactions between species that amplify the probability of spillover.
One Health approach and risk identification
Adopting a One Health perspective to understand host-pathogen dynamics, including pathogen presence, distribution, evolution, and transmission characteristics, can highlight spillover risk factors. Awareness of these risks provides valuable intervention points to reduce spillover effects. While some situations may require a multi-pronged approach, focusing on prevention has proven to be more economically efficient than relying solely on reactive measures.
Changes in the human-animal-environment interface
Historical and ongoing changes in the interactions between humans, animals, and the environment provide valuable insights for prevention. Factors such as hunting, land use change, agricultural practices, food systems, infrastructure development, and animal trade patterns are critical in developing prevention strategies. Investing in research that explores these socio-economic changes is paramount.
Vector-borne disease considerations
Understanding habitat suitability, climate change, and host abundance is essential for vector-associated disease risk assessment. Even in the absence of pathogen presence or virulence data, awareness of exposure pathways between interfaces can help pinpoint critical control points. Changing human behavior can reduce the risk of infection in a wide range of ways.
Determinants of spillover risk
Direct activities such as hunting, urbanization, biosecure livestock farming, animal trade, and deforestation influence spillover risks. Additionally, the risks are further exacerbated by overarching factors such as climate change, food security, animal and human health concerns, socio-economic disparities, and animal welfare practices. Addressing both direct and broader influencers is essential to overall spillover prevention.