Norwalk virus

Nature 
Norwalk-type viruses are extremely infectious. You can be infected with a Norwalk virus by consuming contaminated food or water or just by touching things an infected person has touched.
Incidence 
In 1998, 270 passengers aboard a cruise ship suffered from gastroenteritis caused by a Norwalk virus. The source of the outbreak was never found.
Type 
(G) Very specific problems