Sana Sohail is a third-year undergraduate at the University of Chicago studying biological sciences and art.
In our fast-paced, globalized world, where you can board a plane this afternoon and be halfway around the world tomorrow, infectious diseases can just as easily travel and indiscriminately devastate communities. In the words of the World Health Organization (WHO), “a communicable diseases in one country today is the concern of all”. With the non-stop travel and trade between countries, it can seem impossible to monitor the spread of an infectious disease, much less treat or stop its effect. The challenges involved in disease surveillance are heightened further in developing countries that may not have the infrastructure to recognize or treat infections, let alone track their movement.
Recent outbreaks of viruses like Ebola and Zika have not only caused a world-wide panic around the origin and symptoms of these diseases, but also their transmission and surveillance. Recurring headlines like “South China province reports 11th Zika case” and “New Ebola case confirmed in Liberia” are evidence to some level of disease tracking, but how is this effectively enforced? Understanding how these outbreaks are predicted and monitored is crucial not only for the sake of saving thousands of lives, but also for confronting the deficiencies in infectious disease surveillance (and their consequences). Very frequently, these diseases are transmitted from animals or plants to humans. Despite this, outbreaks are often reported in the limited scope of human health, omitting an important link in the movement of infections. These outbreaks also damage economies, causing massive losses in livestock and tourism (such as with Brazil, Zika, and the Olympic Games), and this isn’t even taking into account the suffering and loss of life that results from inadequate surveillance. Setting aside the life-saving work done by the WHO, there are several countries that are not members of the United Nations and thus do not share the same information and standardized reporting guidelines. Even within and between states in the US, there are differences in procedure that could weaken the surveillance system. However, in general, infectious disease information flows across several sectors: local, state, national, and global levels that emphasize, above all, communication.
IT TAKES A VILLAGE
For most countries, the local level of disease surveillance consists of clinicians, pharmacists, hospitals, veterinarians, public health workers, and farms (to list just a few). The vigilance of these experts in recognizing symptoms and patterns in their patients is critical, as they report their cases and information to state health officials and health departments. Also functioning at the local level are various laboratories testing specimens and patient samples that contribute to data collected by the state.
The fundamental role of surveillance on a local level cannot be overstated; each state collects information from individual reports, clinicians, hospitals, and public health agencies in an effort to “aggregate, triage, and investigate” these reports to determine the urgency and location of a disease.
THE NATION’S WATCHFUL EYES
Organizations like the Center for Disease Control (CDC) in the United States operate at the national level, holding significant influence over the nation’s coordinated response to outbreaks. The CDC receives a state’s compiled reports through the National Electronic Disease Surveillance System (NEDSS), which allows for streamlined electronic communication between the national level and the public health departments and clinical health care systems that make up the state and local levels. According to the CDC, the transfer of this information from the state is voluntary. It is at this level that a nationwide picture of infectious diseases can be developed, where an outbreak in one state can be recognized and announced. In the meantime, similar outbreaks are tracked in other, at-risk parts of the country. Other national organizations that do similar work include the Foodborne Disease Outbreak Surveillance System and Department of Disease Global Emerging Infections System, as well as some non-governmental organizations.
Before describing the World Health Organization’s role within the global level of infectious disease surveillance, there are several ancillary organizations and systems that also work actively at a global level by taking advantage of the millisecond-by-millisecond reporting capabilities of social media sites like Twitter and Facebook. ProMED, the Program for Monitoring Emerging Diseases, is a global electronic reporting system that tracks and shares information on infectious disease outbreaks 24/7 by making use of “all sources…free of political constraints”. You can join the free ProMED listserv here.
HealthMap is similar to ProMED, but uses more visual representations of aggregated real-time data. Designed by a team at Boston Children’s Hospital, HealthMap makes use of the real-time information from various social media, news sites, and academic reports to “achieve a unified and comprehensive view of the current global state of infectious diseases”. Working around the clock like ProMED, HealthMap’s interacting system (pictures) is critical for both the general public and the various levels within disease surveillance. The same team also came up with Outbreak Near Me, a mobile application of the system. Sickweather is another mobile monitor of infectious diseases that specifically parses through social networks and hashtags to provide updates about infections like the flu and chickenpox. HealthMap, in collaboration with USAID and UC Davis’ PREDICT surveillance program, has created a system that focuses on “zoonotic disease emergence” (diseases that can be transmitted between animals and humans). Not understanding or controlling these infections in animals and insects leaves the infrastructure in any country, no matter how developed, fragile in the face of disease like Zika and avian (H5N1) flu.
The integration of modern technology is crucial—disease surveillance methods are often criticized for their “passiveness”. Nothing can be monitored or addressed if nothing is reported or noticed in the first place (once again, placing a heavy weight on the individual roles at the local level). Waiting for such information uses up valuable time needed to combat the spread of deadly infections. Although there are several advantages to passive surveillance (it is continuous over long periods and less resource-costly), it also has many drawbacks aside from the loss of time. As stated before, while there are several systems in place to report cases, these procedures are not always standardized or reliably enforced. Furthermore, a great gap emerges in areas or countries where health care is not readily available or equally accessible. This means that there are entire populations where cases of infectious diseases are not reported, and therefore, not monitored. Incorporating the timeliness of social media into disease surveillance allows such a system to be more actively engaged with the people it is implemented to protect.
THE WORLD AT LARGE
Returning to the WHO, the global level of surveillance is dominated by this organization’s efforts and collaborations with the United Nations’ Food and Agriculture Organization (FAO) and World Organization for Animal Health (OIE). Relying on reports from its member nations, the WHO receives reports from each country’s Ministry of Health, various public health departments and agencies, national laboratories, NGOs, and other collaborators. Also present at this level are UNICEF and the International Red Cross and Red Crescent Movement.
The WHO is also behind the International Health Regulations, a set of laws intended to standardize and coordinate surveillance information and tracking among participating countries. Equally as important, these regulations also cover surveillance and disease management at crucial points of transmission: sea ports, airports, and other high traffic areas where exchange between countries is common.
Despite all of the coordination and collaboration between local, state, national, and global levels of infectious disease surveillance, the reality is that much of the global population lives in developing countries where such an infrastructure does not exist or is not well-established. Economic damage aside, a lack of proper surveillance in these countries allows diseases like cholera and meningitis to run rampant, destroying communities through major morbidity and mortality. Increasing education and awareness of these diseases and their symptoms, controlling animal and plant infections before they “spillover” into humans, and strengthening both surveillance and communication technology at all levels in these countries, are priorities in stopping the spread of infectious diseases.