Influenza is an annual visitor for many people in the US, especially senior citizens with reduced immunity to a host viruses that cause the disease. Every year due to the diligent work of immuno chemists, anti viral vaccines are readied after determining the type of virus that can be expected to emerge. It is to the credit of that country that millions of doses of vaccines are made ready for vaccinating those most vulnerable to the Flu and mortality is really contained within reasonable limits. How about the so called stomach virus which also makes its visits during winter as these tiny bugs can survive freezing conditions as well as temperatures as high as 60C! The usual symptoms of vomiting and/or diarrhea can occur within 10-48 hours after getting the infection through food or water. One has to admire the power of this virus when it is recognized that it is not "culturable" under laboratory conditions and hence no vaccine can ever be prepared as a preventive step.Here are interesting facts about this "almighty" vector.
"I've never understood the appeal of cruises. They sound boring, too much time sitting on your butt at sea, not enough running around on land. But passengers on a recent 10-day cruise through the Balkan Sea had a lamer than average journey thanks to an outbreak of norovirus. Exactly how many of the ship's passengers fell victim to the miserable gastrointestinal malady is up for grabs (as many as 400 according to fellow passengers, just a handful if you ask the PR department). The "plague ship", as it was re-christened by unhappy customers (pretty classy given the circumstances, I'd have gone with "ship of loose stools" or the "S.S. Blaaaauuurrrggh"), was back at the dock last week, but we're sure to see plenty more cases of norovirus in the coming months. It isn't called the "winter vomiting bug" for nothing.* Four hundred cases on one cruise may sound improbable, but norovirus is a mighty pathogen. Like many a food-borne illness, it's transmitted via the fecal-oral route. Feces of an individual infected with the virus is somehow ingested by an uninfected person – often in contaminated food or water – where it replicates in the digestive tract and continues the cycle. Vomit works too. It's gross, I know. But don't worry, because we're likely talking about a minuscule amount of puke or poo in your food. Part of the charm of the winter vomiting bug is its drastically low infectious dose. As few as 18 viral particles can be enough to make you thoroughly sick.**"
Interestingly this virus called Norovirus is found to be very resilient surviving for 15-20 days on surfaces when contaminated from those carrying them and can easily be transmitted to scores of people coming in contact with such surfaces. Many a time people, imagining that their drinking water is chlorinated, come to grief following Norovirus attack through water samples chlorinated at sub-optimal level. Those consuming food through bare hands without use of spoons or forks can also be affected if hands are not washed thoroughly before touching the food. Tropical countries like India more or less escape from Norovirus epidemic because this virus does not breed well at higher atmospheric temperatures. According to people who had experienced Norovirus attack are mostly while touring in groups with close contacts most frequent providing greater opportunity to the virus to transfer itself to others. Probably it is advisable to be doubly vigilant when travels for long duration necessitating frequent and close contacts and sharing of food and water.