7 outbreaks of Norovirus in Vegas

The Southern Nevada Health District Office of Epidemiology has, since March 29, 2014, identified 7 clusters and outbreaks of acute gastroenteritis illness in the Las Vegas area. Venues associated with these clusters and outbreaks include a hotel conference, several private gatherings, and long–term and memory-care facilities. Seventeen persons reported seeking medical care and 2 persons were hospitalized in association with the hotel conference.

norovirus-2Testing by the Southern Nevada Public Health Laboratory (SNPHL) confirmed NoV in multiple stool specimens obtained from ill persons.

SNHD, SNPHL, and the Nevada Division of Public and Behavioral Health (NDPBH), Office of Public Health Informatics and Epidemiology collaborated on the investigation and response to these outbreaks.

Strict hand hygiene is the most important method to prevent NoV infection and control transmission. Proper hand washing with soap and running water for at least 20 seconds is the most effective way to reduce NoV contamination of the hands. Hand sanitizers might serve as an adjunct in between proper hand washings, but should not be considered a substitute for frequent soap and water hand washing.

The efficacy of sodium hypochlorite (chlorine bleach) has been widely documented to disinfect human NoV from environmental surfaces. When possible, chlorine bleach solution should be applied to hard, nonporous, environmental surfaces at a concentration of 1,000–5,000 ppm (5–25 table-spoons household bleach [5.25%] per gallon of wa-ter) and leave in place for at least 4 minutes. A list of EPA-approved commercial cleaning products that are effective against feline caliciviruses (which in-clude NoV) is available at http://www.epa.gov/oppad001/list_g_NoV.pdf. Personnel performing environmental services should adhere to the manufacturer’s instructions for dilution, application, and contact time.

Additional infection control measures for healthcare and LTCFs are included in the SNHD Guidelines for the Prevention and Control of NoV in Extended Care Facilities and Nursing Homes available online at http://www.southernnevadahealthdistrict.org/health-care-providers/norovirus-guidelines.php