Norovirus Recognition, Transmission Prevention, and Reporting

The purpose of this memo is to alert healthcare facilities to the symptoms of norovirus, to reinforce appropriate measures for preventing transmission, and to clarify reporting requirements for facilities regulated by the Office of Quality Assurance.

Issue

Over the past year, significant norovirus outbreaks occurred among residents and staff of nursing homes and assisted living facilities, and among hospital staff. Noroviruses are a group of viruses that cause acute gastroenteritis. Outbreaks are more prevalent during the winter months but, can occur at any time. Illness is characterized by the sudden onset of nausea and vomiting, watery diarrhea, and abdominal cramps. Symptoms may also include chills, body aches, and fatigue. Dehydration is the most common complication and may require intravenous replacement fluids. The duration of illness is usually one to three days.

Noroviruses are highly contagious and are found in the stool or vomitus of infected persons. Infected person are contagious at the onset of symptoms and for at least three days to two weeks after recovery. Transmission occurs primarily through the fecal-oral route following direct contact with a person who is, or has been, recently ill. Droplet transmission may occur from vomitus. The viruses can also be transmitted orally by touching surfaces contaminated with the virus, by eating contaminated food, or by drinking contaminated water. Noroviruses may remain viable for up to 12 days on surfaces and in carpets.

Additional information about noroviruses is available from the Centers for Disease Control at: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus.htm (exit DHFS) or from the Wisconsin Division of Public Health at: http://dhfs.wisconsin.gov/communicable/factsheets/norovirus.htm.

Transmission Prevention

The implementation of Standard Precautions is emphasized, with particular attention to thorough hand washing (use of warm running water and soap for at least 15 seconds, although alcohol gel may be used in the absence of running water unless hands are visibly soiled) after using the toilet, providing personal care, touching contaminated surfaces, and before handling food and eating. Contact Precautions are indicated when providing care that involves direct physical contact. Infected persons should not prepare food while they have symptoms and for up to three days after recovery.

Information regarding disinfection of surfaces is available from the Division of Public Health. Additional information on Standard and Contact Precautions is available from the Centers for Disease Control at http://www.cdc.gov/ncidod/dhqp/gl_isolation_standard.html (exit DHFS).

Reporting Requirements

Healthcare facilities, including community based residential facilities and adult family homes, are required to report outbreaks of suspected communicable gastrointestinal diseases to their local public health departments.

The local public health department will request additional clinical information required for the purpose of surveillance, control and prevention of the communicable disease. Based on information received, the public health department will also provide direction for any additional steps that need to be taken, such as the collection of stool samples.

Guideline for Reporting an Outbreak

Monitor and document the number of gastrointestinal illness daily, to establish normal baseline. Norovirus outbreaks can generally be defined as an increase in illness above the expected or "normal" rate.

One general guideline that can be used as a rough indicator of a norovirus outbreak is a doubling in number of ill residents over that of normal expected illnesses due to vomiting and/or diarrhea and at least two of the following symptoms: nausea, abdominal cramps, chills, fever, sweats, headache, muscle aches, body ache, and fatigue.

In some cases, if a facility has lab evidence of infection with organisms such as E. coli O157, Salmonella, Shigella, Cryptosporidium, and Giardia, reporting the outbreak, initiating an investigation and implementing prevention measures might be appropriate as soon as two or more cases are seen.

If an outbreak is suspected, the local health department should be notified immediately.

Any further question should be directed to the Local Division of Public Health in your county.

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DHS

Wisconsin Department of Health Services

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