Norovirus: ‘Tis the Season

Indiana Epidemiology Newsletter
December 2006

Lynae Granzow, BS
Enteric Epidemiologist

‘Tis the season for snow, holidays, and noroviruses. Since November, this noro season has started off with a bang in outbreaks, particularly in long-term care (LTC) facilities. Although commonly called “stomach flu”, it is important to not confuse Norovirus infection with influenza, a respiratory illness characterized by fever, sore throat, cough, and muscle aches. Although the seasonality of both Norovirus infection and influenza overlap, the transmission routes and prevention methods are very different.

Noroviruses are shed primarily in stool and are very easily transmitted by the fecal-oral route, e.g., consuming contaminated food or beverages or having close contact with someone who is ill. The predominant symptoms of Norovirus infection are nausea, diarrhea, and vomiting. Some people may experience a low-grade fever, chills, headache, muscle aches, and fatigue. This virus has a quick incubation period, ranging from 12-96 hours and averaging 24-48 hours. While there is no treatment available for Norovirus infection besides some good couch time and fluid replacement, ill persons will recover on their own within 1-2 days.

Prevention is the key to limiting the spread of infection, since there is no effective treatment and people can be contagious up to two weeks after recovery. To help prevent Norovirus infection:

  • Encourage good hand hygiene. Handwashing is best, since alcohol-based sanitizer gels may not be effective against Norovirus.

  • Thoroughly wash contact surfaces and contaminated areas with a 1:10 dilution of bleach water. Bleach should be prepared daily and kept out of sunlight. Bleach disinfection of sensitive surfaces may be followed by disinfection with alcohol or other disinfectant to prevent damage.

  • Exclude anyone who is symptomatic with diarrhea and/or vomiting from high- risk settings:

    • Long-term care facilities

    • Health care facilities

    • Daycare facilities

    • Food establishments

    • Schools

Recommendations for Public Health Professionals

This is a good time to check the quantity and expiration dates of the ISDH 7A specimen submission containers. Since Norovirus season is under way, it is a good idea to have a sufficient quantity of 7A containers available. To report a gastrointestinal outbreak within your community, please contact your District Field Epidemiologist or Lynae Granzow at 317.234.2808.

Due to ISDH Laboratories changing facilities the following announcements are provided:

  1. The new general ISDH Laboratories phone number (317-921-5500), will be covered effective January 16, 2007. Prior to January 16, 2007, the ISDH general lab number (317-233-8000) will still be covered.

  2. The preferred method for requesting shipping containers including the 7A for enteric specimens is to send the request by e-mail to This will not change after the move, which is planned to be completed by January 29, 2007.

REMINDER: all submitters must contact the appropriate staff at the ERC prior to submitting samples, so that the ERC can determine if the testing is of public health significance which requires ISDH Laboratory involvement.