Why are highly contagious diseases kept in labs?

The Centers for Disease Control and Prevention (CDC) stores samples of viruses and diseases to keep us safe because the only way to learn about disease and control outbreaks is to know your enemy. 
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As we've seen in movies like "Contagion" or "Outbreak," infectious diseases can be terrifying. They kill people, spread like wildfire, cause mass chaos and collapse entire governments. Even though these movies are fictional, they're not that far from the truth. So why on Earth would scientists and researchers keep a stash of every contagious disease out there in their labs?

The Centers for Disease Control and Prevention (CDC) stores samples of viruses and diseases to keep us safe. That might sound counterintuitive, but the only way to learn about disease and control outbreaks is to know your enemy. When an outbreak occurs, the first step in halting it is to identify, or diagnose, it. Once a disease is diagnosed, scientists and medical professionals can take steps to control it. During the control phase, researchers can work on the pathogen to find a way to treat it and later, with skill and luck, prevent it.


Researchers also keep samples of contagious disease for surveillance. The World Health Organization (WHO) works internationally to keep tabs on diseases affecting public health. This global surveillance system, through which participating countries report communicable diseases, allows WHO to identify emerging diseases or learn of new outbreaks of existing diseases. This allows the control mode to go into effect that much faster.

One of the most developed worldwide virus partnerships is influenza surveillance. Because the influenza virus mutates into different strains, it can become vaccine resistant. Each year, by analyzing past and developing data coming in about the flu virus, researchers decide which strains will be included in the annual flu vaccine. So, every year, the flu shot adapts, just as the virus itself adapts.

Sometimes these samples can even help scientists "go back in time" and solve the mystery of unexplained deaths. For example, the bacterium Legionella pneumophila caused a large outbreak of Legionnaire's disease in 1976. Once researchers isolated the bacterium, they looked at tissue samples that resembled the current outbreak and found there had been unidentified outbreaks in 1956 and 1947 [source: CDC].

Whenever a local hospital or government agency becomes aware of an outbreak of infectious disease, or if a patient presents with symptoms never seen before, they notify the CDC and send in samples for identification. Local labs and professionals package and ship samples in accordance with CDC-approved guidelines to ensure safety. The guidelines include using trained lab workers, having redundant controls and individually tailored safeguards for each lab in place, and being subjected to unannounced safety inspections [source: CDC].

Unfortunately, accidents still happen.


Pros and Cons of Keeping Disease Stockpiles

In 1999, the World Health Organization set a deadline for the United States and Russia to destroy their remaining stockpiles of smallpox, but as of yet they haven't complied.
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From 2008 through 2012, more than 1,000 laboratory incidents occurred that posed a risk to humans or animals [source: Young]. Many of these reported incidents were minor, but some were serious enough that lab workers needed medical attention. Because of bioterrorism laws, the names and locations of labs weren't released, but USA Today obtained incident reports from the CDC. The accidents included ones in which workers and animals were inadvertently infected, in some cases with bacteria and viruses that can have serious complications. The lab workers recovered, and any infected animals were euthanized. In some cases, labs were fined and their research suspended.

In June 2014, at least 75 people at the CDC in Atlanta faced potential exposure to the deadly anthrax virus [source: Mohney and Besser]. Lab workers were moving live samples to another lab while not wearing full personal protective gear. They were informed the virus had been inactivated, but that turned out to be wrong. Virus spores could have escaped into the air and been inhaled at any point during this process. All exposed employees were offered vaccinations, treatment and health monitoring by the CDC. As of this writing, none of them have exhibited symptoms.


Anthrax is one thing, but why do we keep diseases that have already been eradicated, such as smallpox, in stock?

The last known case of smallpox occurred in Somalia in 1977, and because of a worldwide vaccination effort, WHO declared the disease eradicated in 1980 [source: Salzberg]. However, one lab in the United States and one lab in Russia still have stocks of the virus.

Scientists at both labs say we need to keep the virus in case of a bioterrorism attack, in order to quickly develop and distribute vaccines. However, the WHO believes it's unsafe to keep this virus. If the smallpox virus gets out, it could cause a devastating outbreak, as people are no longer vaccinated against it.

In 1999, WHO set a deadline for the United States and Russia to destroy their remaining stockpile of smallpox, but they haven't complied [source: Salzberg]. Some experts believe we have enough data and DNA information to develop vaccines without needing the live virus and continue to campaign for the remaining stockpiles of smallpox to be destroyed [source: Stein].

Pros and cons exist for keeping live strains of infectious diseases in labs. On one hand, keeping these viruses helps save lives through research and worldwide surveillance. On the other, many believe that means we're one accident away from a doomsday scenario.

Learn more about the CDC in "Level 4: Virus Hunters of the CDC - Tracking Ebola and the World's Deadliest Viruses" by Joseph B. McCormick, Susan Fisher-Hoch and Leslie Alan Horvitz. HowStuffWorks picks related titles based on books we think you'll like. Should you choose to buy one, we'll receive a portion of the sale.


Lots More Information

Related Articles

  • Centers for Disease Control and Prevention. "A CDC Framework for Preventing Infectious Diseases." October 2011. (Sept. 23, 2014) http://www.cdc.gov/oid/docs/ID-Framework.pdf
  • Centers for Disease Control and Prevention. "Infectious Diseases Pathology Branch (IDPB)." Jan. 18, 2013. (Sept. 23, 2014) http://www.cdc.gov/ncezid/dhcpp/idpb/at-work/index.html
  • Centers for Disease Control and Prevention. "Investigating Unexplained Illness & Death." Dec. 7, 2012. (Sept. 23, 2014) http://www.cdc.gov/ncezid/dhcpp/idpb/unexplained-deaths/index.html
  • Centers for Disease Control and Prevention. "Laboratory Safety at CDC." Aug. 15, 2014. (Sept. 23, 2014) http://www.cdc.gov/about/lab-safety/
  • Mohney, Gillian and Richard Besser. "75 Potentially Exposed to Anthrax in CDC Breach." June 19, 2014. (Sept. 23, 2014) http://abcnews.go.com/Health/75-potentially-exposed-anthrax-cdc-breach/story?id=24218884
  • Salzberg, Steven. "It's time to destroy the U.S. smallpox reserves." Forbes. March 13, 2011. (Sept. 23, 2014) http://www.forbes.com/sites/sciencebiz/2011/03/13/its-time-to-destroy-the-u-s-smallpox-reserves/
  • Stein, Rob. "Should last remaining known smallpox virus die?" The Washington Post. March 8, 2011. (Sept. 23, 2014) http://www.washingtonpost.com/wp-dyn/content/article/2011/03/08/AR2011030802087.html
  • World Health Organization. "Global infectious disease surveillance." 2014. (Sept. 23, 2014) http://www.who.int/mediacentre/factsheets/fs200/en/
  • Young, Alison. "Hundreds of bioterror lab mishaps cloaked in secrecy." USA Today. Aug. 17, 2014. (Sept. 23, 2014) http://www.usatoday.com/story/news/nation/2014/08/17/reports-of-incidents-at-bioterror-select-agent-labs/14140483/