Preventing and Containing Outbreaks

Preventing and Containing Outbreaks

Without proper control, diseases can lead to widespread outbreaks and be harmful to public health. Fortunately, there are many methods available to contain diseases.




Biology, Health

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It can start out as simple as a cough. An unsuspecting passerby drifts a bit too close, inhaling infected droplets. Not soon after, the contagion has spread to the population at large, creating an outbreak. Fortunately, there are numerous measures in place to prevent and manage such catastrophes.

Nonpharmaceutical Interventions

The simplest measures, known as nonpharmaceutical interventions (NPIs), are forms of prevention that require no vaccines or prescriptions. This includes staying home when you are sick and washing your hands. These methods are particularly effective against pathogens that can be spread through person-to-person contact. NPIs can be used in conjunction with other prevention measures, such as vaccines, to strengthen an individual’s chances of avoiding infection. Because NPIs, like handwashing, are simple and inexpensive, they are the first line of defense for people, and if a vaccine is not available, it may be the only prevention tool that individuals can use.

Unfortunately, prevention methods do not always work. If someone is affected by an infectious disease, it is important for them to seek treatment as soon as possible. The earlier treatment can begin, the quicker an individual can be healed, reducing the potential for the disease to spread to others. For example, treating genital herpes through medication alongside condom use reduces the chance of passing on the disease. In some cases, it may be advisable to treat people who have been in contact with the patient before they begin showing symptoms.


Once health practitioners identify cases of the disease, practitioners and health officials can take steps to prevent further infections. The measures that experts take to stop the spread of disease vary and depend on the pathogen in question. A common method for reducing the likelihood of disease spread is through quarantine, which involves separating an individual who may have come into contact with the infectious agent from other people.

The United States has a comprehensive quarantine system at ports and border crossings to limit infectious diseases entering the country. There are twenty of these quarantine stations across the United States, and they are staffed by the Centers for Disease Control and Prevention (CDC). The CDC may quarantine any traveler suspected of carrying an infectious disease or they may opt to send them to a hospital or home for confinement. The CDC also has the authority to issue a federal quarantine, but this measure is rarely needed. Within state lines, it is up to the state to regulate what agency has the authority to quarantine, though it is usually the local health authorities.


Isolation is another method, distinct from quarantine, to prevent disease spread. During isolation, a sick individual is separated from those who are not sick. This is in contrast to a quarantine, which separates an individual who may have been exposed to the contagion, but is not exhibiting symptoms. Similar to quarantines, the CDC has the authority to isolate an individual suspected of carrying a contagious disease that would harm the public.

The exact procedures of both isolation and quarantine depend on the severity of the disease in question. Chickenpox, for example, is highly contagious and can be passed through skin contact or through the air. When infected, children are instructed to not attend school, so they do not infect their classmates. However, because the disease is relatively mild, those who are infected can be isolated at home. On the other hand, more serious and deadly diseases, such as Ebola or measles, may require intervention from the state. In such cases, it is illegal to break an isolation or quarantine order. Additionally, severely ill individuals are likely to be isolated in a hospital setting.

Closing Public Spaces

Authorities may also choose to close public spaces to prevent the spread of disease. For example, schools may shut down if there is an increase in influenza cases. While the CDC provides guidance for more severe global outbreaks, it does not officially determine if schools should close for the flu; instead, it is up to the school. However, recent evidence suggests that school closures can help limit exposure to the contagion and mitigate the spread of disease.

Food Recall

A different approach is needed if the contagion is spread through food ingestion. Food can be recalled if it is mislabeled or if there is a physical contaminant, such as plastic, or to prevent the spread of foodborne pathogens, such as salmonella. When an infectious agent contaminates food, it is imperative to pull the food in question off the shelves, thereby preventing more individuals from getting sick after consuming tainted food.

The U.S. Food and Drug Administration (FDA) is responsible for regulating most food products, except for meat, poultry, and some egg products, which are regulated by the U.S. Department of Agriculture’s Food Safety Inspection Service (FSIS). However, when there is a foodborne illness, the CDC launches an investigation. Manufacturers and distributors can also contact the FDA or FSIS with food-safety concerns. If the threat could seriously endanger the public, the FDA begins to warn the public through the media.

Some foods are more prone to harboring pathogens than others. Although undercooked meat often gets a bad reputation for being a source of bacteria, leafy greens, such as lettuce and spinach, are more often responsible for foodborne illnesses. In 2018, romaine lettuce caused widespread concern because of E. coli contamination. Fortunately, officials have taken action in light of recent lettuce contaminations, including the 2011 Food Safety Modernization Act, which improves sanitation standards. Additionally, modern advances in genetic sequencing technology are making it easier for experts to track outbreaks and identify their source.

The methods used for containing disease are wide-ranging, and the methods that are employed depend on what disease needs to be controlled. From the large-scale policies and procedures of government agencies to individuals washing their hands, we all have a role to play in preventing outbreaks.

Media Credits

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Tyson Brown, National Geographic Society
National Geographic Society
Production Managers
Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Last Updated

October 19, 2023

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