Norovirus

Continuing with water related diseases.  The number 3 cause of drinking water outbreaks is Norovirus.

Noroviruses are a group of related viruses (Calicivirus) that cause nausea, vomiting, diarrhea, abdominal cramps and fever in humans.   It is the most common cause of acute gastroenteritis in the US, causing more than 20 million cases each year.  Formerly, known as Norwalk viruses named after the original strain, which caused an outbreak in a school in Norwalk, Ohio, in 1968

How do you get it?

• Fecal contamination of water and food, such as salads, in restaurants, camps, schools
• Uncooked or partially cooked oysters, clams, cockles or other shellfish that have been harvested from sewage-polluted estuaries
• Contaminated ice

• It is a highly contagious and resistant virus which is why outbreaks are common

Vaccine and Treatment

There is no vaccine and no drug to treat people who get sick from the virus.  Antibiotics won’t work because it's caused by a virus, not a bacteria.  Therefore, treatment is symptomatic and aimed at preventing dehydration. 

Prevention

• Once again good hygiene – WASH YOUR HANDS 
• Environmental surfaces should be disinfected using a chlorine bleach solution 5-25 tablespoons of household bleach per gallon of water
• Food and water safety is very important
• Noroviruses are relatively resistant and are able to survive freezing and temperatures as high as 60°
• Noroviruses can survive in up to 10 mg/liter chlorine 
•  US EPA guidelines for municipal water systems recommend residual chlorine concentrations of at least 0.2 mg/liter  

Historical Outbreaks

• In 2010 twenty-one NBA players and three staff from thirteen teams in eleven states were affected. 
• Butter Cream Frosting Incident.  In 1982, one man mixing icing for a Minneapolis-St. Paul area bakery caused some 3,000 illnesses.  Investigators discovered the infected worker mixed the uncooked icing in a giant vat with his bare arms and hands. 
• 1987 two related outbreaks involving ice produced by a company that supplied both Philadelphia’s Franklin Field stadium and to a museum fundraiser in Wilmington, Delaware.  The cause was traced to flooding of the company wells from an infected stream.