Biggest outbreaks in every state from the past decade

- Illnesses: 86
- Hospitalizations: 1
- When: March 2013
- Where: long-term care/nursing home/assisted living facility

Norovirus sickened patients at a long-term care facility in Delaware in March 2013. Health-care facilities are the most common settings for viral outbreaks in the United States, according to the CDC.

- Illnesses: 110
- Hospitalizations: 31
- When: June 2016
- Where: fair, festival, other temp or mobile services; grocery store

Salmonella sickened more than a hundred people in South Dakota in 2016. The CDC estimates salmonella causes about 1.2 million illnesses and 450 deaths in the United States every year.

- Illnesses: 130
- Hospitalizations: 0
- When: March 2014
- Where: long-term care/nursing home/assisted living facility

An illness outbreak sickened more than 100 people in a long-term care facility in Vermont in 2014. Outbreaks can spread quickly in places that are enclosed or where people live close to one another.

- Illnesses: 155
- Hospitalizations: 1
- When: April 2009
- Where: data not available

Food-borne norovirus struck New Jersey residents in 2009. Only a tiny amount of norovirus particles is needed to contaminate food and water to make people sick, according to the CDC.

- Illnesses: 180
- Hospitalizations: 0
- When: December 2012
- Where: long-term care/nursing home/assisted living facility

Residents of a North Dakota long-term care facility fell ill in an outbreak in 2012. Health experts say outbreaks can be devastating to patients already ill or infirm living in such homes.

- Illnesses: 189
- Hospitalizations: 0
- When: April 2016
- Where: long-term care/nursing home/assisted living facility

Nearly 200 people fell ill in a long-term care facility in Connecticut in 2016. Residents of such facilities may already be in weak health, making them vulnerable to infection.

- Illnesses: 191
- Hospitalizations: 0
- When: May 2016
- Where: school/college/university

Nearly 200 students became ill in May 2016 at an Oregon school. Close quarters and shared spaces make it easy for the virus to spread in schools, according to the CDC.

- Illnesses: 200
- Hospitalizations: 1
- When: June 2013
- Where: camp

Two hundred people got sick in an outbreak at a Montana camp in 2013. Health experts say illness can move rapidly in settings such as camps, where food, sleeping quarters, and bathrooms are shared.

- Illnesses: 205
- Hospitalizations: 1
- When: December 2016
- Where: restaurant (sit-down dining)

An outbreak of E.coli was linked to a popular Mississippi restaurant, Captain Al's Steak and Shrimp in Gulfport, where people who had eaten there fell ill in December 2016. Which food or beverage was to blame was never specifically determined. The restaurant reopened in January 2017.

- Illnesses: 221
- Hospitalizations: 0
- When: December 2016
- Where: school/college/university

Children at a Cranston, R.I., elementary school fell sick with norovirus in December 2016. The source was not determined. Nearly half of the kindergarten class was sickened. The school closed briefly for disinfecting.

- Illnesses: 223
- Hospitalizations: 0
- When: March 2015
- Where: prison/jail

In March 2015, an outbreak of salmonella sickened prisoners at Alabama's Holman Correctional Facility. The Southern Poverty Law Center, which had filed a lawsuit over conditions and medical care in the state's prisons, linked the outbreak to overcrowding and unsanitary facilities.

- Illnesses: 229
- Hospitalizations: 26
- When: January 2012
- Where: data not available

More than 200 people fell ill and 26 were hospitalized in a January 2012 outbreak in Nebraska. Outbreaks can occur at any time, but some viruses are more commonly spread in winter months.

- Illnesses: 268
- Hospitalizations: 2
- When: May 2016
- Where: child day care

The bacterial disease shigellosis affected children attending day care in southeastern New Mexico in May 2016. The bacteria is usually transmitted from fecal matter and often spreads amongst children as they may not wash their hands thoroughly enough.

- Illnesses: 275
- Hospitalizations: 15
- When: June 2015
- Where: grocery store

A salmonella outbreak sickened hundreds of customers at the Boise Co-op in June 2015. Some cases were traced to the Co-op's kiosk at Boise Airport. Health authorities linked the illness to turkey, tomatoes, and onions in the store's deli, and customers who later filed lawsuits said they became ill after eating sandwiches from the popular grocery store. The store closed temporarily for a clean up and added safety practices.

- Illnesses: 276
- Hospitalizations: 0
- When: February 2010
- Where: data not available

Authorities investigated a norovirus outbreak in the District of Columbia in February 2010. Highly contagious, the virus causes vomiting and diarrhea.

- Illnesses: 280
- Hospitalizations: 0
- When: March 2009
- Where: school/college/university

Swimmers and coaches at a competition at the University of Maine fell ill in March 2009 to what was determined to be elevated levels of chloramine in the pool. State health officials said the contamination grew from compounds in the pool such as perspiration that reacted with chlorine disinfectant to produce chloramines that were released in the air. Ventilation fans had been inadvertently turned off. The contamination caused respiratory problems, eye irritation, diarrhea, and vomiting. The swim meet drew about 600 swimmers from across the state.

- Illnesses: 281
- Hospitalizations: 71
- When: June 2016
- Where: restaurant (sit-down dining)

Diners fell sick with hepatitis A in June 2016 at a chain of sushi restaurants in Hawaii. The outbreak was traced to tainted frozen scallops from the Philippines that were served raw. Two people died, and the chain reached a multimillion-dollar settlement with people who were exposed.

- Illnesses: 282
- Hospitalizations: 1
- When: November 2012
- Where: restaurant (sit-down dining)

Patrons at a newly opened Casper, Wyo., buffet-style chain restaurant were infected with norovirus in November 2012. The outbreak was traced to dozens of employees believed to have contracted the virus and spread it to patrons while working. The exact source was never pinpointed. The restaurant closed briefly for cleaning and reopened without further cases reported.

- Illnesses: 284
- Hospitalizations: 0
- When: December 2014
- Where: school/college/university

In December 2014, hundreds of students were sickened at a New Hampshire school. Schools are prime locations for outbreaks to erupt, given that students share close quarters and the behaviors of young children in particular can contribute to transmission.

- Illnesses: 325
- Hospitalizations: 0
- When: November 2011
- Where: data not available

More than 300 people were sickened in a November 2011 outbreak in Florida. Common settings for outbreaks are health-care facilities, restaurants, schools, and cruise ships, according to the CDC.

- Illnesses: 332
- Hospitalizations: 0
- When: September 2013
- Where: data not available

Illness struck Iowans in September 2013, and more than 300 people reported becoming sick. Many outbreaks go unreported at the time they occur, especially if no cause appears obvious.

- Illnesses: 352
- Hospitalizations: 0
- When: February 2011
- Where: fair, festival, other temp or mobile services; prison/jail

More than 300 people were sickened in Oklahoma in an outbreak in 2011. An illness is considered an outbreak when there are more cases than expected in an area or season.

- Illnesses: 352
- Hospitalizations: 5
- When: March 2009
- Where: long-term care/nursing home/assisted living facility

Norovirus caused hundreds of people to fall ill in a Wisconsin facility in 2009, and one person died. The CDC says the virus contributes to as many as 800 deaths a year, mostly among young children and elderly people.

- Illnesses: 353
- Hospitalizations: 5
- When: February 2010
- Where: hotel

In February 2010, attendees at a youth conference held at a North Carolina hotel fell ill with C. perfringens. Health investigators determined the bacteria was found in undercooked chicken served by a catering company.

- Illnesses: 355
- Hospitalizations: data not available
- When: August 2011
- Where: data not available

Hundreds of people fell ill in New York in 2011 with shigellosis, from bacteria found in fecal matter of people with diarrhea. It can spread by touching contaminated surfaces, changing diapers, or swallowing contaminated pool water.

- Illnesses: 364
- Hospitalizations: 5
- When: February 2016
- Where: event space

Hundreds of people fell sick with norovirus in Maryland in February 2016. The virus is the leading cause of food-borne illness and acute gastroenteritis in the United States.

- Illnesses: 365
- Hospitalizations: 6
- When: August 2012
- Where: prison/jail

Salmonella spread among inmates at a maximum security prison in Arkansas called the Tucker Unit, near Pine Bluffs, in August 2012. Visitation and prison transfers were canceled to halt any possible further spread.

- Illnesses: 369
- Hospitalizations: 13
- When: January 2014
- Where: community/municipality

A toxic chemical spill from an above-ground storage tank into West Virginia's Elk River in January 2014 contaminated the water supply for about 300,000 residents, and hundreds fell ill, reporting vomiting, nausea, rashes, and headaches. The governor ordered a state of emergency as well as warnings not to use water in nine counties; these warnings were in place for 10 days. One of the chemicals spilled was used in a process that separates impurities from coal. Authorities found a lack of inspections of the tank, which had small holes caused by corrosion.

- Illnesses: 406
- Hospitalizations: 0
- When: February 2013
- Where: school/college/university

Students at a Massachusetts high school complained in February 2013 of stomach illnesses diagnosed by authorities as norovirus. It spread quickly, forcing the closing of the regional high school in West Newbury. The source was not officially determined.

- Illnesses: 408
- Hospitalizations: 0
- When: March 2014
- Where: school/college/university

The University of Pittsburgh at Johnstown was the site of a suspected norovirus among students who complained of gastrointestinal symptoms in March 2014. Events were canceled for over a weekend for cleaning and disinfecting of campus buildings and the school's dining services.

- Illnesses: 416
- Hospitalizations: 0
- When: February 2017
- Where: school/college/university

An outbreak of norovirus sickened hundreds of students in Colorado in February 2017. The virus is transmitted by people eating or drinking contaminated food or liquids, touching contaminated spaces and putting their fingers in their mouths and having direct contact with an infected person such as caring for them or sharing food or utensils.

- Illnesses: 420
- Hospitalizations: 3
- When: December 2017
- Where: restaurant (sit-down dining)

Diners at a Seattle bar and restaurant were sickened with norovirus in December 2017. Health authorities shut down the eatery, but never discovered the exact food or drink responsible.

- Illnesses: 438
- Hospitalizations: 0
- When: October 2017
- Where: school/college/university

Hundreds of Kentucky students fell ill with norovirus in October 2017. According to the CDC, the virus causes as many as 21 million infections a year nationwide.

- Illnesses: 459
- Hospitalizations: 52
- When: July 2016
- Where: parks (community/municipal, waterpark); private residence; subdivision/neighborhood; public outdoor area

In the summer of 2016, a cryptosporidiosis outbreak struck at pools and water parks in Arizona.The water-borne germ known as crypto is transmitted in fecal matter and spreads easily.

- Illnesses: 544
- Hospitalizations: 0
- When: November 2012
- Where: data not available

South Carolina was the site of a norovirus outbreak in November 2012 that sickened more than 500 people. The CDC says outbreaks of norovirus are common and occur most often from November to April.

- Illnesses: 594
- Hospitalizations: 31
- When: October 2008
- Where: data not available

Salmonella made nearly 600 people sick in California in 2008. The bacteria causes diarrhea, fever, and cramps that can be especially risky for young children, older adults, and people with weakened immune systems.

- Illnesses: 597
- Hospitalizations: 3
- When: June 2013
- Where: public outdoor area

Participants and spectators in an obstacle-filled Tough Mudder endurance race in June 2013 in Michigan fell sick with nausea, vomiting, diarrhea, and abdominal cramps that was confirmed to be norovirus. Health officials concluded the race course was contaminated by a participant who was ill. They said those who got sick were probably exposed on the course, since the illness is linked to mud and muddy water getting in the mouth. More than 22,000 participants and spectators attended.

- Illnesses: 620
- Hospitalizations: 3
- When: January 2015
- Where: hotel/motel

Visitors to Tennessee's famed Opryland Hotel in January 2015 fell ill due to norovirus; conferences and meetings were cancelled during a cleanup. An all-clear was given at the end of the month, although a new case was reported the following month.

- Illnesses: 628
- Hospitalizations: 2
- When: April 2010
- Where: community/municipality

More than 600 people fell ill in April 2010 in Utah in a confirmed outbreak of Campylobacter jejuni that spread by drinking contaminated water. The bacteria is found in the intestines of farm animals.

- Illnesses: 636
- Hospitalizations: 3
- When: January 2016
- Where: restaurant

Customers attending performances at a dinner theater in Overland Park, Kan., in January 2016 fell ill with diarrhea and stomach cramps in what was determined to be an outbreak of norovirus and C. perfringens. Investigators suspected items on a salad bar were the likely source.

- Illnesses: 638
- Hospitalizations: 0
- When: July 2016
- Where: waterpark

An illness that broke out at a Columbus, Ohio, water park in July 2016 was confirmed to be cryptosporidiosis, which causes diarrhea. The Zoombezi Bay water park is run by the Columbus Zoo and Aquarium. The microscopic parasite is spread in water, and area pools were closed to halt the spread.

- Illnesses: 670
- Hospitalizations: 0
- When: December 2011
- Where: long-term care/nursing home/assisted living facility

Norovirus was the suspected culprit in the sickness of hundreds of stricken patients and two deaths at a long-term care facility in Minnesota in 2011. More than half of all norovirus outbreaks in the United States take place in long-term facilities, the CDC says.

- Illnesses: 699
- Hospitalizations: 0
- When: May 2012
- Where: data not available

Norovirus sickened nearly 700 people in Texas in May 2012. The CDC says the virus is the leading cause of outbreaks from contaminated food in the United States.

- Illnesses: 708
- Hospitalizations: 0
- When: February 2016
- Where: school/college/university

An outbreak of norovirus sickened several hundreds of students in 2016 at a Virginia school. Outbreaks of the virus are most common in closed communities such as schools, cruise ships, and long-term care facilities.

- Illnesses: 742
- Hospitalizations: 1
- When: October 2011
- Where: data not available

Schools in a region of southern Georgia were forced to close temporarily due to an outbreak of shigellosis. It causes diarrhea, fever, and stomach pain.

- Illnesses: 800
- Hospitalizations: 0
- When: November 2009
- Where: data not available

An outbreak in 2009 that sickened hundreds of people in Louisiana was suspected to be C. perfringens, bacteria that can be found on raw meat and poultry. C. perfringens is one of the most common types of food-borne illnesses in the United States, according to the CDC.

- Illnesses: 809
- Hospitalizations: 0
- When: June 2015
- Where: data not available

Hundreds of people took ill in early summer of 2015 in Missouri due to the spread of the shigella bacteria. Found in diarrheal stool, it is most commonly contracted and spread by young children.

- Illnesses: 1,000
- Hospitalizations: 0
- When: April 2017
- Where: school/college/university

Students at schools in the Las Vegas area were diagnosed in April 2017 with norovirus. Highly contagious, it spreads by infected people, contaminated food, or water, and by touching contaminated surfaces.

- Illnesses: 1,101
- Hospitalizations: 53
- When: March 2014
- Where: data not available

In March 2014, an outbreak of shigellosis sickened more than a thousand people in Indiana. The shigella bacteria, typically found in developing countries, spreads from fecal matter. The Indiana outbreak was associated with younger children, who can transfer it easily due to poor hand washing habits and by putting things in their mouths, authorities said.

- Illnesses: 1,341
- Hospitalizations: 0
- When: July 2013
- Where: data not available

Illinois was the site of a cyclosporiasis outbreak in 2013, a rare intestinal infection spread by consumption of water contaminated by the parasite cyclospora. It can be linked to raspberries, basil, snow peas, and mesclun lettuce, and is more typically found in tropical and subtropical areas.

- Illnesses: 2,500
- Hospitalizations: 0
- When: April 2013
- Where: school/college/university

The CDC reported a norovirus outbreak among Anchorage high school students in April 2013. The virus is highly contagious and spreads easily in closed spaces such as classrooms. Authorities did not pinpoint a single common source.