Norovirus is also known as Norwalk-like virus or small round structured virus SRSV. It causes acute gastroenteritis (vomiting and diarrhea).

1. Food or water contaminated by infected food handlers or at its source e.g. shellfish.
2. Person to person spread occurs via direct and indirect contact with faeces and vomitus.
3. Contaminated environment (e.g. toilet, swimming pool) can be a major source of outbreak.
4. Aerosol from contaminated environment or projectile vomiting.

After exposure to the virus, there will be an incubation period of 24-48 hours.

1. Vomiting (predominant early symptom)
2. Abdominal pain
3. Watery diarrhea
4. Fever (low-grade, not present in all cases)
5. Dehydration (may occur in young children or elderly)
6. The illnesses usually last for 1-2 days without chronic sequel

Special notes:

1. Norovirus is highly infectious.
2. Persons become infectious from symptom onset and may last for 2 weeks after recovery.
3. Control on personal hygiene of infected persons, and thorough environmental cleansing (e.g. household bleach (5.25%) diluted in 1:49 water) are key to prevent secondary spread.
4. University hostels and areas with high human density are at risk for norovirus outbreak.
5. Students and staff should be alert for symptoms of vomiting and diarrhea, and prompt for advice from University Health Clinic.

English version

• Centre for Health Protection of Department of Health - Norovirus Infection
  http://www.chp.gov.hk/en/content/9/24/33.html

Chinese version

• 衞生署衞生防護中心 - 諾如病毒感染
  http://www.chp.gov.hk/tc/content/9/24/33.html