Authors: Shannon Bocquet, Amelia Crabtree, and Laura Dell'Antonio
Introduction
Over the past 20 months, the COVID-19 pandemic has highlighted the threat that biological agents, specifically infectious diseases, pose. Within one year, there were over 84 million confirmed cases and 1.8 million documented deaths globally. However, this is far from the first time that an infectious disease has resulted in staggering and tragic death rates; in the 14th century, the Black Death (plague) killed as many as 150 million people, decreasing the European population by 30-50%, and the 1918 Spanish flu (H1N1 influenza pandemic) killed 50-100 million people worldwide. Furthermore, considering current trends, it is unlikely that this will be the last pandemic we, as a society, will face. Metabiota estimated that in the next 25 years, there is a 47-57% chance the world will experience another pandemic or epidemic that kills at least as many people as COVID-19, if not more. Infectious diseases result not only in a devastating loss of life, but are a growing threat to global health, the global economy, and global security.
Biological weapons and bioterrorism, laboratory accidents that result in pathogen leaks, and naturally-occurring infectious diseases all present threats to global biosecurity.
Biological Weapons and Bioterrorism
On the surface, bioterrorism may seem to pose the largest threat to biosecurity to the global community. The Monetary Database indicates 55 terrorism events involving biological agents between 1960 and 1999, and only a few where terrorists sought to inflict mass casualties. Only eight of the attacks were fatal, resulting in a total of 29 deaths and 31 injuries; comparatively, in 1995 alone, infectious diseases caused 17 million deaths worldwide, contributing to a far more significant burden on society and threat to biological security. Generally, fears surrounding bioterrorism tend to be much greater than the threat itself. As seen with the Amerithrax attacks in 2001, any whisper of a man-made biological agent generates mass fear and chaos.
The method of deployment, in this case, resulted in only five deaths, though the number of people potentially exposed in the series of mailings was well into the thousands. Ultimately, the psychological and economic impact of the attacks was apparent as those with even the potential of exposure to B. anthracis were prescribed antibiotic regimens, others refused to open any mail out of fear of getting sick, and over $1 billion was spent on nation-wide decontamination efforts. Arguably the most successful bioterror attack was the Rajneeshee religious group’s use of salmonella in 1984, infecting over 750 individuals but causing no deaths. The attack demonstrated the difficulty of detecting and attributing bioterror attacks, as the Rajneeshee’s role was not suspected until an informant tipped the FBI off a year later.
Historically, biological weapons have required extreme investments of time and money to develop and maintain. Furthermore, their unpredictable effect and imprecise targeting precluded them from becoming primary weapons systems. The United States started their bioweapons program in the early 1940s, eventually becoming a larger focus of the military at the start of the Cold War, while the Soviet Union’s bioweapons program likely began sometime in the 1920s. The Soviets focused on developing bomblets and sprayers and organized the anti-plague institutes, with the goal of surveilling naturally occurring pathogens and assessing of those pathogens’ bioweapon potential. Although the U.S. ceased its offensive weapons systems in 1969, the Soviet program continued up to the collapse of the USSR in 1991. Despite the efforts of the Soviet bioweapons program, conventional weapons and nuclear weapons continued to be developed simultaneously, reinforcing that biological weapons would never replace conventional warfare methods. While the threat from biological weapons is ever-present, the Biological Weapons Convention reduces the likelihood of a bioweapon attack globally compared to other biosecurity threats.
Laboratory Leaks
Human error in high-biocontainment laboratories, without a doubt, also pose a pandemic threat. Incidents that result in potential exposure to pathogens frequently occur in biosafety level 3 and 4 (BSL-3 and -4) laboratories and could lead to undetected or unreported laboratory-acquired infections. This, in turn, can lead to the release of a disease into the community external to the laboratory. An example of this is the 1977-78 H1N1 influenza epidemic, colloquially referred to as the “Russian flu”, which resulted in an estimated 700,000 deaths. The outbreak was likely not a natural event as the virus' genetic sequence was identical to the sequence of a strain from the 1950s. Although there are various explanations for the 1977 epidemic, more recent publications focusing on gain of function research have strengthened the hypothesis that the virus may have escaped from a laboratory. A further example would be the 2007 foot and mouth disease (FMD) outbreak in the UK. The outbreak was caused by a derivative of a virus strain handled at two FMD laboratories in Surrey that possibly leaked via broken pipework and unsealed, overflowing manholes. The accident resulted in infections in nearby farms and the culling of over 2,000 animals, highlighting that laboratory accidents are not only a threat to humans but also animals.
As a result of increasing numbers of BSL-3 and -4 laboratories across the globe, more biosafety associations have been established to promote safe laboratory practices; the African Biosafety Association and Biosafety Association for Central Asia and the Caucasus are two of the most recent creations. These, along with national oversight organizations, are drawing from existing biosafety standards and practices. This iterative process, and potential for global standards, promotes safer laboratory practices that will decrease the likelihood of laboratory accidents that could threaten global biosecurity.
Recent discussions regarding the origins of COVID-19 highlight the impact that escaped pathogens from high-containment labs can have on global health security. The recent report from the Director of National Intelligence shows that the U.S. Intelligence Community was unable to conclude whether the virus naturally emerged through a zoonotic spillover event or if it occurred due to accidental exposure in the Wuhan Institute of Virology. Given this 50-50 assessment of the origins of COVID-19, a “once in a generation pandemic”, the overall threat of a laboratory accident to biosecurity is clearly high. However, the likelihood of a laboratory accident resulting in a widescale pandemic is low, COVID-19 potentially being an exception. Along the same trends as the likelihood of a bioterrorist incident, those working in labs with potentially pandemic pathogens are presumably highly trained experts in their respective niches of biology. With this in consideration, the probability of such scientists having an accident in a lab where they are exposed to an agent, then not following proper containment protocols, ultimately enabling the release and spread of a laboratory agent in the outside world, is low. Not to say that this is an impossibility, but too many variables would need to align for a small-scale exposure of highly trained professionals to pose a significant threat to global biosecurity.
Emerging and Re-Emerging Infectious Diseases
While man-made events and laboratory accidents should be taken seriously and require attention for risk assessment and prevention of future occurrences, the events causing the most significant threat to global biosecurity are naturally occurring diseases. Emerging diseases are diseases that cause an outbreak of a previously unknown disease or are known diseases that have recently had a significant increase in incidence or geographic range; in contrast, re-emerging diseases are diseases that were once public health threats, either globally or within a particular geographic area, and then declined dramatically but are again becoming a public health concern. These diseases are a significant burden on public health and economic stability worldwide and have been throughout history.
60% of all infectious diseases and up to 75% of emerging diseases are zoonotic in origin, meaning that these diseases jumped between species from animals to humans, or from humans to animals. These zoonotic diseases are responsible for approximately 2.5 billion cases of illness and 2.7 million human deaths annually. As previously mentioned, SARS-CoV-2 has had a devastating impact on the globe, and with an increasing number of emerging diseases, we will likely experience another pandemic in our lifetimes. That said, our understanding of the causes of emergence is incomplete. Since 1980, there have been a number of newly emerging and re-emerging viral epidemics and pandemics, including HIV in 1981, SARS in 2002, H5N1 avian influenza in 2003, H1N1 influenza in 2009, MERS in 2012, Ebola in 2013 and 2018, Zika in 2015, and COVID-19 in 2019.
Each of these viruses either transmitted from animals to humans or through an insect vector. These viral emergences are occurring more frequently for many reasons, including urbanization and deforestation, climate change, and changing diets. Since 1990, more than 80 million hectares of forest have disappeared, putting humans in more contact with animals and viruses that were previously unknown or rarely seen. Urbanization is not only helping spur on deforestation as more arable land is needed to feed the world population but is also increasing the proximity in which people live to each other. In May 2018, 55% of the world population lived in urban areas; by 2050, that is expected to increase to 68%.
Additionally, viral outbreaks are more likely to spread widely because of the ease of mobility around the world. The advent of air travel connected the globe in a way that had never been possible before; in March 2019 alone, there was an average of 176,000 flights globally each day. As a result, pathogens can spread across the world in a matter of hours via airplane, an impact of globalization highlighted in the early stages of the COVID-19 pandemic. It is also important to highlight that not only human diseases pose a threat to biological security. For example, the African Swine Fever (ASF) outbreak in East Asia that started in 2018 has resulted in the loss of over 40% of China’s pig stock and the preventative killing of a quarter of the global pig population, equating to a financial loss of $141 billion. Therefore, to tackle emerging diseases and re-emerging diseases, engaging from a One Health perspective is essential by considering human, animal, and environmental health in tandem.
In addition to the list of known pathogens that are of pandemic potential, both scientists and policymakers are concerned of an unknown pathogen, often referred to as “Disease X”. It represents the knowledge that a severe international pandemic could be caused by a pathogen currently unknown and was first included in the WHO’s list of priority pathogens in 2018. The difficulty that Disease X poses is that there will be no knowledge about the pathogen prior to its emergence regarding its transmissibility, infectiousness, possible treatments, or vaccines, rendering the global population helpless to its spread.
Mitigating Risks to Global Biosecurity
The risk of emerging and re-emerging diseases is not new. Mitigation efforts for the emergence of novel pathogens include standing up sentinel surveillance systems in regions and communities that may be more susceptible to emerging diseases. In order to do this, there would need to be global, widespread availability of pathogen-agnostic diagnostic tests for rapid identification of worrying disease symptoms or disease clusters. However, collecting surveillance data itself is not enough; this data must then be evaluated from a global perspective to identify larger trends or specific areas of concern.
Furthermore, considering most emerging infectious diseases are zoonotic in nature, expanding surveillance capacity at and in areas near wet markets and other animal trading posts is critical. Focusing on testing certain animals known to be reservoirs for pathogens with pandemic potential, such as bats and pangolins, is key to assess spillover risk. Similarly, proactively testing antiviral treatments on virus families could enable the quicker development of treatment options. If certain drugs are found to be effective against similar pathogens, it could indicate efficacy against an emerging disease once the disease is identified and sequenced. While some of these efforts are ongoing, investments in these structural changes fluctuate depending on political, public, and private interests
Additionally, public health measures such as clean water supplies, adequate sewage treatment, sanitary handling of food, and access to primary health care facilities should be accessible for everyone worldwide to prevent the spread of diseases. Ultimately, natural infectious diseases pose the largest threat to biosecurity because of these gaps in primary care and public health systems. As outlined by the 2019 Global Health Security Index, no country’s health system was adequately prepared for a pandemic or other biological event.
Mere months after the report was published, COVID-19’s emergence highlighted these shortcomings. It is crucial to improve public health systems to ensure detection and response to an emerging infectious disease is as quick as possible, ultimately preventing catastrophic global spread. The recent release of the American Pandemic Preparedness report in September 2021 by the Biden administration demonstrates the leaps even the United States must take in order to best equip the country for the next pandemic, but developing countries often lack the resources to do the same. Since the emergence of a disease anywhere in the world is a threat to everywhere, it is also necessary to assist developing countries in establishing or improving their own primary care and public health systems to better prevent, detect, respond, and recover to potentially devastating infectious diseases. Strengthening global primary health care not only improves the detection capabilities for such emerging diseases, but also combats the impact of known communicable diseases such as malaria, AIDS, and tuberculosis. Completely mitigating any threat of emerging infectious disease is unlikely, if not impossible, though a first step is to bolster primary care systems in high-risk regions to mitigate naturally occurring pandemics.
This article was prepared by the authors in their personal capacity. The opinions expressed in this article are the authors' own and do not reflect the view of their place of employment.
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