The CDC reports the new strain, like other norovirus strains, is transmitted person to person, and has been confirmed nationwide for about 50 percent of the recent norovirus outbreaks. In Louisiana, the strain has sickened dozens and forced the closure of some oyster harvest areas. Because the strain is new, few people are immune to it causing more outbreaks.

Norovirus outbreaks are common, and generally those infected recover within one to two days. Much like influenza, norovirus mutates easily, and new strains such as this are common. The CDC name for the new strain, GII.4 New Orleans, includes “New Orleans” in the name because the first confirmed samples came from the Crescent City.

Norovirus symptoms usually begin to show 24 to 48 hours after exposure to the virus. Symptoms usually include nausea, vomiting, diarrhea and stomach cramping. Sometimes people have a low-grade fever, chills, headache, muscle aches and a general sense of tiredness. 

Noroviruses are found in the stool and vomit of infected people. People can become infected with the virus in several ways:

  • By eating food or drinking liquids that are contaminated with norovirus,
  • By touching surfaces or objects contaminated with norovirus, and then placing their hand in their mouth, and
  • By having direct contact with another person who is infected (for example, when caring for someone with illness, or sharing foods or eating utensils with someone who is ill).

"People should wash their hands thoroughly with soap and water after using the toilet, before consuming food, and before preparing food,” said Dr. Jimmy Guidry, State Health Officer.  “If everybody did this, we could prevent a majority of the illness caused by these viruses."

You can decrease your chance of coming in contact with noroviruses by following these preventive steps:

  • Frequently wash your hands, especially after toilet visits and changing diapers and before eating or preparing food.
  • Carefully wash fruits and vegetables, and fully cook oysters before eating them.
  • Thoroughly clean and disinfect contaminated surfaces immediately after an episode of illness by using a bleach-based household cleaner.
  • Immediately remove and wash clothing or linens that may be contaminated with virus after an episode of illness (use hot water and soap).
  • Flush or discard any vomitus and/or stool in the toilet and make sure that the surrounding area is kept clean.

Persons who are infected with norovirus should not prepare food while they have symptoms and for at least two to three days after they recover from their illness. Food that may have been contaminated by an ill person should be disposed of properly. Persons working in day-care centers or nursing homes should pay special attention to children or residents who have norovirus symptoms. This virus is very contagious and can spread rapidly throughout such environments.

The Louisiana Department of Health strives to protect and promote health statewide and to ensure access to medical, preventive and rehabilitative services for all state citizens. To learn more about LDH, visit