Identifying & Isolating Bio-Threats Before They Present

An emerging infectious disease or a bioterrorism attack must be prevented from spreading globally even when the effectiveness of predictive measures and detection programs is in question. In addition to current medical countermeasures, defending against biological threats may require the enforcement of control measures that rely on non-medical public health interventions.

In the field of biosecurity, the often unseen threats of infection during a mass gathering are becoming a much higher priority. Largely because of the growing number of natural or man-made biological agents to which people are exposed, such gatherings have become high-risk targets for possible terrorist attacks. In 2012 alone, various events throughout the world – at the London Olympics, the annual Muslim pilgrimage to Mecca, and the World Expo in Yeoso, South Korea, for example – attracted millions of visitors.

In an era when modern aviation enables people to travel, literally, from anywhere in the world to almost anywhere else in the world within 24 hours or less, the ease of travel has contributed to: (a) the re-emergence of infectious diseases such as polio and tuberculosis; (b) the spread of communicable diseases to regions where some of these diseases were never before experienced (Dengue virus, yellow fever, Ebola); and (c) the emergence of novel and potentially pandemic infectious diseases (H5N1, SARS). Moreover, because certain infectious diseases take several days before appearance of the first symptoms, those infected can return to their home countries without realizing they are also transporting – and possibly transmitting – a potentially dangerous pathogen. For that reason among others, effective biodefense planning will require the adoption of international public health policies based on a global health security platform to improve the biosecurity capabilities of every nation.

Although significant steps already have been taken to augment various medical countermeasure procedures, an effective defense against biological threats necessarily begins by enforcing control measures that rely on non-medical public health interventions to detain not only those already exhibiting symptoms of a pandemic disease but also many others who might reasonably be suspected of having been exposed. The lack of established procedures for quarantining or isolating those who have been infected but are not yet symptomatic can have devastating results. In 1918, for example, as global travel started to increase almost exponentially, and with little or no regard for public health interventions, health officials estimated that one-third of the world population at that time were infected with the so-called “Spanish Flu.”

A similar deadly pandemic would have an even greater impact on today’s much more “globalized” society than it did a century ago. Making this problem even more serious is the fact that public health experts have difficulty predicting patterns of disease transmission in a mixed population. Because the next pandemic or bioterrorism attack cannot be accurately predicted – combined with the fact that the most recent U.S. Government Accountability Office report shows that existing “sentinel surveillance systems” are still not capable of countering such an attack – the use of basic public health measures is probably the most useful tool currently available to effectively mitigate biosecurity threats.

Whether the real danger is the natural spread of emerging infectious diseases or a malicious biological attack, the potential for loss of life is nonetheless immense – and the threat to the nation’s economy, infrastructure, and stability is great. For these reasons, and others, it is important that a medical countermeasure response program include provisions for quarantine and/or isolation when the threat of a potentially dangerous communicable disease is suspected.

Detaining, Isolating & Quarantining

Although most U.S. hospitals and other healthcare facilities already isolate patients diagnosed as having a communicable disease, the quarantine of others – event participants, airline passengers, etc. – who do not yet exhibit signs of illness but are reasonably believed to have been exposed still meets with resistance. This is despite the fact that enforcing the legal authority to contain an infectious disease can mean the difference between a dozen or so people, rather than hundreds or thousands, being infected with a potentially fatal disease.

Whatever the reason, the challenge of protecting the greater population through the practices of quarantine and isolation almost always evokes ethical and political issues ranging from legal rights and individual liberties to major inconveniences, economic losses, and various personal hardships. Forced social separation also more or less revokes the right to privacy and freedom from involuntary detention, and in extreme cases sometimes seems to promote discrimination of one type or another.

At an airport or any other port of entry, infrared thermal imagers can be used toentify potentially infected persons before a truly definitive medical diagnosis can be made. Although a decrease in social mixing is the only non-medical option currently available to contain an emerging epidemic, the increased burden on the passengers detained may in some cases seem to outweigh the risks posed by dissemination of the infection into a larger population. To streamline the process to at least some extent, airlines follow guidelines established by international aviation and public health organizations that spell out the protocols that must be followed if a passenger with a communicable disease isentified. Those protocols include but are not necessarily limited to: isolation of the infected person(s); communication with medical advisory channels; and, when advisable, contact with legal authorities at the ports of entry.

The World Health Organization recognizes such concerns and specifically states on its website that, “after all voluntary measures to isolate such a patient have failed,” quarantine efforts should meet the criteria spelled out in the “Siracusa principles” – i.e., the list of civil and political rights enunciated by the U.N. Commission on Human Rights at a 1984 meeting in Siracusa, Sicily. To ensure that the rights of the detainees are being protected, at least one of the following must be met: (a) the restriction must be provided for and carried out in accordance with the law; (b) the restriction must be in the interest of a legitimate objective of general interest; (c) the restriction must be necessary in a democratic society to achieve that objective; (d) there must be no less-intrusive and/or restrictive means available to accomplish the same objective; and (e) the restriction must be based on scientific evidence and not drafted or imposed arbitrarily – i.e., in an unreasonable or otherwise discriminatory manner.

Fortunately, the quarantine of infected people meets with less resistance when the health, rights, and needs of the individual are prioritized. Earning trust in a quarantine situation by making the situation completely transparent to travelers who are detained will usually make the establishment of authority easier to accept. In situations where a person believed to have been infected refuses containment, the public health official should and would be granted the authority needed to use the minimal means available – e.g., police force – to restrain that person.

Racing the Clock

Time is a key variable in the success or failure of implementing a quarantine strategy that puts an acceptably safe distance between the non-infected population and those who have been exposed to a communicable disease. The 2003 Severe Acute Respiratory Syndrome (SARS) outbreak provides an excellent example of how the basic public health interventions available at that time helped control the global spread of the disease. The SARS outbreak traveled from its origins in Guangdong Province, China, to Hong Kong, Vietnam, Taiwan, Canada, and Singapore. Five international flights were associated with and played an unhelpful part in the SARS transmission – which spread from an infected passenger to other passengers and crew members. Although an estimated 500 or so infected people died as a result of the epidemic, by isolating known cases, quarantining contacts, minimizing social gatherings, and limiting the spread of infection through local and international travel, further spread of the disease was limited.

To stop a natural or man-made disease from spreading – when the asymptomatic period is longer than the actual travel time involved, and/or when preventive actions are initiated as a result of reasonable suspicion rather than outward signs of illness – biodefense preparedness plans must begin at the site of origin. Whether through a stronger engagement in international organizations such as the World Health Organization or through direct collaboration with the host nations of mass gatherings, ensuring that biosecurity threats are mitigated both as quickly and as effectively as possible begins by strengthening the prevention and response capabilities at ground zero.

In addition to serving as an investment in national security, such capacity building – both in disaster management and in public health preparedness – also provides a firm foundation for local development, peace, and stability. Efforts to mitigate andentify biosecurity threats, therefore, must be the essential components of a cooperative, sustainable, and truly global effort before the next version of the 1918 Spanish Influenza or other lethal and rapidly spreading disease isentified.

For additional information on: U.S. Government Accountability Office Report on Biowatch, visit

World Health Organization’s “ Guidance on human rights and involuntary detention for xdr-tb control,” visit

Significant contributions to this article were made by Kristine Rose of the Johns Hopkins Bloomberg School of Public Health.

Kristine Rose is a Research Assistant in the International Health Department at the Johns Hopkins Bloomberg School of Public Health, where she is pursuing a Masters degree in Public Health. She previously received a Ph.D. in Microbiology and Immunology from the Oregon Health and Science University School of Medicine. Her current efforts are focused on global health, epidemiology, child survival, vaccination strategies and point-of-care diagnostics.

Patrick P. Rose

Patrick P. Rose, director for pandemic and catastrophic preparedness at the National Association of County and City Health Officials, holds a Ph.D. in infectious diseases and is a subject matter expert on national security issues related to public health security. He works with federal and local stakeholders to address requirements and gaps that produce vulnerabilities in public health security. In addition, he supports efforts domestically and internationally in the field and at the policy level to reduce the proliferation of biological weapons and to increase public health security awareness. These efforts include promoting greater engagement in the Global Health Security Agenda. He is an alumnus of the Emerging Leaders in Biosecurity Initiative and serves as an adjunct assistant professor at the University of Maryland Department of Epidemiology and Public Health.



No tags to display


Translate »