Norovirus is a highly contagious virus that commonly causes acute gastroenteritis, an inflammation of the stomach and intestines. This infection typically leads to sudden onset of symptoms such as vomiting and diarrhea. While uncomfortable, norovirus illness is usually not severe and most people recover within one to three days.
How Norovirus Spreads
Norovirus is primarily transmitted through the fecal-oral route, not through airborne droplets like the common cold or influenza. This means the virus spreads when microscopic particles of feces from an infected person are ingested by another individual. While forceful vomiting can generate some aerosols containing virus particles, direct contact and contaminated surfaces are the main modes of transmission.
Direct contact with an infected individual is a common way the virus spreads. This can occur, for example, when caring for someone who is ill with norovirus, such as a child or an elderly family member. Consuming food or water contaminated with norovirus is another significant route of transmission. This often happens if food is handled by an infected person who has not washed their hands thoroughly.
Shellfish harvested from contaminated waters can also carry the virus if eaten raw or undercooked. Additionally, touching surfaces or objects that have been contaminated with norovirus, such as doorknobs, railings, or shared utensils, and then touching one’s mouth before handwashing, can lead to infection. The virus can survive on surfaces for days, making environmental contamination a persistent source of spread.
Effective Prevention Strategies
Rigorous hand hygiene is the most effective measure to prevent the spread of norovirus. Frequent and thorough handwashing with soap and water for at least 20 seconds is crucial, especially after using the restroom, changing diapers, before eating, and before preparing food. Alcohol-based hand sanitizers are less effective against norovirus compared to soap and water because the virus lacks a lipid envelope that alcohol can disrupt.
Disinfection of contaminated surfaces is also an important prevention strategy. After someone has been sick, it is important to clean and disinfect contaminated areas promptly. Bleach-based cleaners are effective against norovirus; a bleach solution is recommended for disinfecting hard, non-porous surfaces.
Proper food safety practices are important to prevent foodborne norovirus outbreaks. Individuals who are sick with norovirus should avoid preparing food for others while symptomatic and for at least two to three days after symptoms resolve. Cooking shellfish thoroughly can also reduce the risk of infection.
Limiting contact with others while symptomatic and for a period after recovery helps contain the spread of the virus. Sick individuals should stay home from work or school to prevent transmitting the virus to colleagues or classmates. This isolation helps break the chain of transmission in community settings.
Importance of Rapid Response
The high contagiousness of norovirus underscores the importance of rapid response to prevent widespread outbreaks. Only a very small number of virus particles are needed to cause illness in an individual. This low infectious dose means that even minimal contact with contaminated surfaces or food can lead to infection.
Norovirus is also highly resilient and can survive in the environment for days on various surfaces. This environmental persistence means that contaminated areas can remain infectious for an extended period if not properly cleaned and disinfected. Prompt and thorough action, including proper hand hygiene and environmental cleaning, is therefore important to interrupt the spread of this virus.