Microbiology - Norovirus
Norovirus Fact Sheet - Printer Version, PDF, 22 KB)
Norovirus (NV) symptoms include sudden onset of vomiting accompanied by watery diarrhea, nausea, abdominal cramps, fever, or headache, lasting anywhere from 12-60 hours. The incubation period is approximately 24-48 hours. Transmission may occur person-to-person or through the fecal-oral route via fecally contaminated food or water. Infection prevention and control measures include hand washing after using the bathroom and before handling food items, wearing masks when cleaning contaminated areas, handling soiled linens as little as possible, flushing or discarding any vomitus and/or stool in the toilet and making sure that the surrounding area is kept clean, and cleaning all surfaces with germicidal product (10% bleach).
NCSLPH tests for norovirus during outbreak situations only. Local health departments should telephone the NC Communicable Disease Branch of the North Carolina Division of Public Health epidemiologists (919-733-3419) when enteric disease outbreaks are suspected in a day care center, nursing home or restaurant. In addition, the Food, Lodging and Institutional Sanitation Branch of the Division of Environmental Health should be notified at (919) 733-2905 when restaurant- or institution-associated illness is suspected.
To ensure that the event is eligible for outbreak investigation, contact the Communicable Disease (CD) Branch epidemiologists (919-733-3419). After approval by the CD Branch epidemiologists, submit one stool specimen for each patient and request NV testing. Raw stool must be collected in a sterile container such as a sterile urine specimen cup. Raw stool is acceptable for NV testing only and not for isolation of enteric bacteria. Preferably for NV testing, stool samples should be submitted in commercially available enteric transport medium such as Cary-Blair Transport Medium (BD, Sparks, Maryland), ETM™ (Alpha-Tec Systems, Vancouver, Washington), or Para-Pak® Enteric Plus Transport System (Meridian Bioscience, Inc., Cincinnati, OH). Please submit at least five and no more than ten specimens for testing. For NV testing only, stool samples can be maintained at 4ºC for 3-5 days until shipped. For samples that may be tested for enteric microorganisms, specimen shipment should occur with 24 hours of collection. Samples submitted in enteric transport medium will be tested for the presence of NV first. If NV is not detected in any of the outbreak samples and enteric testing is requested, the specimens will be screened for enteric microorganisms.
Cary-Blair transport medium for collection of feces is also available for purchase from the laboratory mailroom on-line at https://slphreporting.ncpublichealth.com/labportal. Each specimen must be clearly labeled with the patient's name and accompanied by DHHS form #3390 (PDF, 345 KB). To ship specimen to the NCSLPH, place completed Enteric Bacteriology DHHS form #3390 (PDF, 345 KB; one form for each specimen) in the outer container to avoid contamination in case of breakage or leakage. Follow all relevant packaging and shipping requirements. Unlabeled specimens will not be tested.
For submissions of five or more samples, NV testing will be performed within one business day of receipt and results reported within two business days of receipt. For submissions that contain less than five specimens, NV testing will be performed when five samples from the same outbreak are received. In this case, it may be five to seven business days until NV results are reported.
The results will be reported for a positive NV test as “NV RNA detected by RT-PCR” and for a negative NV test as “NV RNA not detected by RT-PCR”. The submitter will be notified by telephone of the results and the official report will be forwarded by mail. Additionally, the CD Branch epidemiologists will be notified of the tests results.
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