Biosurveillance

• ALSO KNOWN AS: Biological surveillance, biomonitoring

Definition

Biosurveillance is a systematic process of surveying the environment for viruses, bacteria, fungi, and other pathogens to detect disease in humans, animals, and plants. The process also characterizes outbreaks of such disease.

Overview

Biosurveillance combines disease surveillance with public health surveillance, both of which depend upon data collection and analysis with the goal of early disease detection to thwart a potential outbreak. Diseases may be defined by incubation and infectious periods, source, and transmission route, while outbreak characterization uses general analytic techniques, such as spatiotemporal distribution, incidence, mortality, and cohort or case-control studies. Biosurveillance proceeds from continuous data collection to confirmation of cases with a feedback loop back to data aggregation. Environmental investigations include food chains, vectors, weather, geography, the number of people who became ill, and those at risk.

In the United States, the major use of biosurveillance is to track emerging and reemerging infectious diseases such as H1N1 influenza, food-borne diseases caused by resistant strains of Escherichia coli and Salmonella, sexually transmitted diseases (STDs), and human immunodeficiency virus infection, which may also be transmitted by contaminated blood products or through maternal transmission.

In the United States, government agencies conduct biosurveillance at the levels of state and local health departments, which then report to federal agencies such as the Centers for Disease Control and Prevention (CDC), a division of the Department of Health and Human Services (HHS). The CDC collects, analyzes, and distributes national disease occurrence and mortality rates to state and local health authorities and the public. Also part of the HHS is the Assistant Secretary for Preparedness and Response (ASPR), which directs public health and preparedness activities. The National Biosurveillance Integration Center, run by the Department of Homeland Security (DHS), identifies, tracks, and characterizes biological events using publicly available data and data collection research. The National Biodefense Science Board (NBSB) is a panel of experts that provides data and information to federal agencies to guide decisions and planning. Globally, the US collaborates with organizations such as the World Health Organization (WHO), the Pan American Health Organization (PAHO), and the South East Asia Regional Office (SEARO) on matters of bioequivalence.

Before 2000, biosurveillance systems included the National Electronic Telecommunications System for Surveillance (NTESS) and PulseNet, the national subtyping network comprising state and local public health laboratories and federal food regulatory laboratories that perform molecular surveillance of food-borne infections. Systems in place after 2000 include the cloud-based BioSense and other early warning systems, such as the Real-time Outbreak and Disease Surveillance System (RODS).

Numerous decision-making tools, such as Bayesian inference, may be applied to the detection of an outbreak of infectious disease. The importance of the decision-making process cannot be overestimated when providing alerts to the public. The costs versus benefits of false alerts must be weighed against the goal of protecting the population at risk.

Influenza Surveillance

The CDC maintains a comprehensive surveillance system for influenza viruses, which mutate from year to year, requiring the collection and characterization of varying types of pathogens. Flu vaccines have to be annually updated in accordance with surveillance data to include relevant strains. Treatment for influenza is determined by laboratory surveillance for antiviral resistance. The impact of influenza on hospitalizations and mortality must also be assessed.

The epidemiology and prevention branch of the influenza division at the CDC collects and analyzes information on influenza activity throughout the year in the United States. Surveillance results are available on the FluView website, which is updated weekly, and the FluView Interactive application allows users to access the same weekly reports but with enhanced interactive features and more in-depth surveillance data information. The influenza surveillance system is a collaborative effort between the CDC and its many partners in state, local, and territorial health departments; public health and clinical laboratories; healthcare providers; clinics; and emergency departments.

The CDC employs five categories of influenza surveillance: viral, outpatient illness, mortality, hospitalization, and a geographic spread of influenza summary. Data in each category is collected, and the CDC distributes this information using the Influenza Hospitalization Surveillance Network (FluSurv-NET). FluSurv-NET is part of the Respiratory Virus Hospitalization Surveillance Network (RESP-NET), which compiled population-based data of confirmed cases of influenza, COVID-19, and respiratory syncytial virus (RSV). Each week, more than 3,400 outpatient healthcare providers around the United States provide data to the CDC. This data includes the total number of patients in each category according to age group. This data can be used to identify age groups at risk for serious illness or death.

Also included in national data are human infections with novel influenza A viruses, pneumonia, influenza mortality from the 122 Cities Mortality System, influenza-associated pediatric deaths, and Aggregate Hospitalizations and Death Reporting Activity. The Emerging Infections Program (EIP) is a population-based network of the CDC and state health departments that assesses the public health impact of emerging infections and examines ways to prevent and control these infections.

Viral Surveillance

Approximately one hundred US and WHO collaborating laboratories, three hundred labs from the National Respiratory and Enteric Virus Surveillance System (NREVSS), and sixty hospital laboratories participate in influenza surveillance. The US-WHO and NREVSS collaborating labs report to the CDC the total number of respiratory specimens tested and the number of positives for influenza types A and B each week. The US-WHO and NREVSS reports are combined and presented on the FluView website.

Routine seasonal surveillance does not count individual flu cases, hospitalizations, or deaths (except for pediatric influenza deaths); rather, it monitors flu activity levels, trends, and viral characteristics through a nationwide surveillance system. The reporting of hospitalizations and deaths by state health departments was initiated at the start of the pandemic H1N1 outbreak in 2009. To avoid the underestimation of cases, the CDC altered this system and asked states to report both laboratory-confirmed hospitalizations and deaths and presumed influenza or pneumonia deaths on cases coded as ICD-9 (International Classification of Diseases). This data is compiled for publication in the CDC’s Morbidity and Mortality Weekly Report (MMWR) and in FluView.

HIV and AIDS Surveillance

The National HIV Surveillance System (NHSS) provides an overview of the most up-to-date epidemiology data on HIV infection in the United States and six US territories and freely associated states. The NHSS's 2012 report (issued in 2014) marked the first time that data was included from each of the fifty states. The CDC funds state and territorial health departments so they can collect data on persons with HIV infection; all personal identifiers are removed before data is transmitted to the CDC through a secure data network. Data are analyzed by the CDC and then displayed by age, race and ethnicity, gender, and transmission category, a significant change in the operation of the surveillance system.

The National Center for HIV, Viral Hepatitis, STD, and Tuberculosis Prevention (NCHHSTP) released an interactive survey data tool, AtlasPlus, in 2012. Using over twenty years of CDC surveillance data, users can create customized charts and tables, discover trends in disease and health in given areas, and learn about the social determinants of health.

In 2008, changes were made to the case definition of HIV infection. To accurately track the epidemic, emphasis was placed on HIV surveillance rather than on acquired immunodeficiency disease syndrome (AIDS) surveillance. HIV testing and linkage to care are essential for identifying persons early.

Approximately 1.2 million persons in the United States are HIV-positive. Data from the National Health Interview Survey can be used to estimate percentages of persons aged eighteen through sixty-four who reported being tested (at any time) for HIV in the United States. The national HIV surveillance system data can help estimate cases and rates of HIV infection, AIDS diagnoses, and late diagnoses of HIV infection. Combined, this data can determine the populations and regions most affected by HIV and AIDS and identify trends in HIV testing and late diagnoses.

Food-borne Disease Outbreak Surveillance

Food-borne pathogens cause an estimated forty-eight million illnesses annually in the United States. Data from outbreak surveillance provides insights into the etiology of these illnesses, the foods in question, and their settings. Foodborne disease outbreak reporting began in the US in 1923 when the Public Health Service began publishing milk-related disease outbreaks. This reporting expanded to all foods and beverages in 1938. In the 1960s, the CDC began publishing morbidity and mortality weekly reports as well as stand-alone booklets containing outbreak data.

In 2011, the CDC began publishing annual summaries on its website, but it moved them to the National Outbreak Reporting System (NORS) Dashboard in 2018. In 2024, the NORS data merged with the Bacteria, Enterics, Amoeba, and Mycotics (BEAM) Dashboard to provide users with comprehensive data through a single online tool. State, local, and territorial health departments use a standard, Web-based form to report food-borne outbreaks using the CDC's Foodborne Disease Outbreak Surveillance System (FDOSS), which is a part of NORS.

Among single, laboratory-confirmed agents of outbreak-associated illnesses, the most prominent in the US include norovirus, campylobacter, salmonella, enterohaemorrhagic Escherichia coli, and clostridium. These outbreaks are often investigated by several agencies. In July 2010, the CDC collaborated with public health officials in several states and with the HHS, FDA, and the Department of Agriculture (USDA) Food Safety and Inspection Service to investigate a nationwide rise in S. enteritidis (SE) infections. Investigators used deoxyribonucleic acid (DNA) analysis of SE bacteria obtained through diagnostic testing to identify cases of illness. They also identified restaurant and event clusters that may have been associated with this outbreak. Investigators determined that eggs contaminated by Salmonella were responsible for the outbreak. In late November 2010, following a recall and ban, the FDA issued permits to some of the affected farms, allowing the resumption of egg sales. Other food sources of foodborne illness in the 2010s included peanut butter, romaine lettuce and mixed greens, cucumbers, CRF Frozen Foods products, and several meat and seafood items.

Impact on Global Public Health

The age of public health globalization has arrived. Global health and global health surveillance have come to the fore, in part because of newly emerging and reemerging infectious diseases. In addition, climate change, poor hygiene and sanitation, lack of economic and food security, political unrest, war, and accelerating threats of bioterrorism have greatly increased global morbidity and mortality from infectious diseases, especially in developing countries.

To counter these challenges, global health surveillance procedures have been updated. Changes were made to the new International Health Regulations (IHR), new global networks were developed, and specific guidelines to monitor emerging diseases and acts of bioterrorism were developed. Global surveillance now provides real-time information about potential outbreaks and epidemics.

The global response to the 2009 H1N1 influenza pandemic demonstrated the benefits of the new global monitoring systems and the importance of WHO in coordinating the international public health community. As a result, valuable models were developed for responding to novel strains of influenza and other pathogenic entities, such as the severe acute respiratory syndrome (SARS) virus. As the number of H1N1 influenza cases increased and rapidly spread, it became apparent that significant resources, intervention, and biosurveillance at the international level would be necessary.

Covid-19 and Biosurveillance

Two years after the COVID-19 pandemic resulted in over one million American deaths, US government agencies acknowledged the need for better early-warning mechanisms to prevent similar episodes in the future. In a June 2022 document, the Government Accounting Office (GAO) described biosurveillance as a process of collecting near real-time biological data of human and zoonotic disease activity. This could be done for early warning, identification of health threats, and situational awareness of disease activity. In doing such, biosurveillance could prompt better emergency preparedness and response. After two years of government efforts to contain COVID-19, the GAO identified insufficient progress in establishing a public health situational awareness and biosurveillance network. The GAO warned that lessons learned from the COVID-19 pandemic and opportunities to improve responses to future public health emergencies were at risk of perishing.

COVID-19 has had the positive effect of spurring innovation in the development of strategies to counter future pandemics. In 2022, one such development emerged in South Korea which employed a strategy named "3T," for testing, tracing, and treating. This effort employs a biosurveillance method that combines information technology and digital applications that go beyond conventional indicator or event-based models. This contact-based biosurveillance system originated following the 2015 Middle East Respiratory Syndrome (MERS) outbreak. A criticism of the South Korean program is that it may create privacy issues as it relies on digital contact tracing and health interventions. The program is perhaps an indication of difficult choices global societies may be forced to make in future emergencies concerning tradeoffs between civil liberties and public safety.

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