Meet Norovirus – The Perfect Infection
As Sheila’s “guest author” today, let me introduce myself. I’m Nora, officially known as norovirus. People sometimes mislabel me as stomach flu – a pet peeve; and I’m not even related to influenza! If you can’t remember my name, at least call me “acute gastroenteritis”, meaning a heck of a lot of vomiting, diarrhea, and abdominal cramping – my specialty. I’m here today to tell you why I’m the best darned virus that ever lived –from my perspective at least, although maybe not from yours!
Norovirus – the Perfect Design
Let me describe myself. I’m slim and trim at only 30 nanometers (0.03 microns) – svelte even for a virus. Influenza is three times my size! Compared to chunky bacteria like E coli at 1500 nanometers – well, I’m truly microscopic. My physique allows me to slip right through just about any water filtration system out there (only nanofiltration systems block me). Once in your water supply, filters rarely get me out!
I keep my figure because I lack a lipid envelope (lipids are fat, don’t you know?). Without lipids, alcohol based sanitizers and detergents don’t faze me. My peers in the germ family have tricked humans into believing that hand sanitizers replace hand washing. Well, hand sanitize all you want. I only worry when I see a sink and soap coming at me– they mean a long damp trip down the drain! But even then, I often sneak by. 80% of people report washing their hands according to recommendations (at least 20 seconds, all hand surfaces, good lather, and friction from rubbing – the stuff that gets rid of me), but hidden camera studies show only 18% actually do this. Good for me, but not for you!
Did I mention I’m tough? My job skills include high endurance and patience. I contentedly hang out on surfaces for weeks or longer, just waiting for a sucker to come along. Some of my favorite resting spots include anything in the bathroom, doorknobs, soiled linens, counter tops food, and food containers. When I spot a chance, I grab a hand, transfer to a mouth, and voilà – target reached!
I have very few mortal enemies. One is boiling water, and the other is bleach, but even then I put up a good fight. You’ll need 5-25 tablespoons of household bleach per gallon of water (5.25%) to kill me on a surface – even more if the solution sits around for more than a day. No wimpy bleach solutions can take me down! People target me with special bleach based cleaners as well, which seems silly. I freely confess that household bleach kills me, so why spend a bunch of money on something that might not work as well? Oh well – that’s capitalism for you!
Noroviruses are great team players. We’re good at infection; we infiltrate and make you sick with a team of only 10-100 viruses. Our methods are top-secret – in fact, no one has figured out how to grow us in a lab for study. I will reveal that we head for your gut and wreak havoc. First of all, we replicate, replicate, and replicate. In 12-48 hours, we make billions of copies of ourselves – no exaggeration! Then we party hardy. Noro, Norah, Norman, Norma, Noreen, Norris, Norbert, Northcliff (he’s visiting from Australia), and I literally bring you to your knees.
We convince your stomach and intestinal cells to dump large amounts of fluid into your gut, then trigger violent diarrhea and vomiting to get rid of it. We speed up passage from below, while simultaneously slowing down stomach emptying. You accumulate a nauseating volume of fluids and food before spewing out your mouth. It’s all pretty uncomfortable, but hang in there! At least we don’t cause much fever or respiratory symptoms.
Why this torture? It’s just a norovirus plot to take over the world. We dump billions of copies into your emesis and feces. When you “expel”, you help spread our copies around. The more violent your diarrhea or barfing, the more you splatter us around the bathroom (or wherever you may be). We have a special talent in creating small droplets of air bound vomit and virus, which travel quite a ways before settling on a new surface.
One recent success was a girls’ soccer team. While travelling, one girl got sick, was quickly isolated, and then sent home. A few days later, her teammates became ill, although they had no contact with her. Magical, you might say! Actually, there was a bag of snacks in her bathroom. Our aerosolized vomit contaminated the bag, and then just waited until the other girls had a snack attack a few days later.
Norovirus – a Considerate Virus
We try not to make you too sick. If we kill off our victims, who will pass us around? We make you miserable for 24-48 hours, and then move on. We don’t choose our targets – we attack whoever ingests us. Unfortunately, this can mean young children, elderly, or the chronically ill. They can’t handle fluid loss and sometimes need intravenous fluids. But give us credit –we kill very few compared to many viruses! 20% of you actually resist us, although the credit lies in your genetic code. The others can’t keep up with our mastery of disguises (rapid mutations and multiple variations). We infect you again and again.
Norovirus – Our Favorite People
I love people who refuse to stay home when sick. They voluntarily transport my viral team around restaurants, nursing facilities, hospitals, cruise ships, and schools. One sick kid in school (maybe mom lacks child care?) can infect everyone – kids are usually not very clean. A sick food handler can pass us to everyone eating there. Currently, we cause over 50% of food-borne illness in the United States. Pretty good for such a tiny thing – don’t you agree?
I love nurses and aides that spread us around facilities. Dedicated healthcare workers rarely stay home even when throwing up, let alone for 2-3 days after symptoms resolve. Our master plan includes sticking with victims several days after they feel better, just to continue shedding virus with every bathroom trip – pretty clever, eh? If they slack off on hand washing when symptoms improve, we still spread! Sick patients and sick caregivers happily transfer us from room to room. We sickened 265 healthcare workers in just one hospital in 2004.
Norovirus Loves Disasters
I love disasters. Crowded shelters are like Candy Land – everyone living only a few feet apart and sharing limited bathrooms (if they even make it to the bathroom). Hand washing drops off the map midst the worries and cares – and people touch everything! In a mega shelter complex after Hurricane Katrina, we sickened 11,000 victims in 11 days (maybe more – they counted only clinic patients). A textbook example of person to person transmission!
Disasters provide us great access to your food. Cooking kills us, but we love hitching rides on fresh produce, shellfish, and ready-to-eat food. Communal kitchens and food distribution centers can distribute us as well – directly from food to your mouth. Just one volunteer with poor hygiene or sloppy cleaning allows food borne transmission – another favorite strategy!
Contaminated water provides another disaster hang-out. With sanitation off-line, people turn to things like plastic bag and bucket toilets or home-made latrines in the yard. We sneak from sewage disposal to near-by water sources, particularly if flood waters or rains help us along. Once in your water, boiling is the only way to kill us. Filters, disinfectants, and solar disinfection (SODIS) – not effective! Plus, if you rinse produce or dishes with infected water – we’re back on your food – a double whammy! (Side note – did you know we survive in ice cubes? Just another example of our superiority!
Norovirus – Keeping Me Away
If you don’t want to party with us, what can you do? Wash your hands – especially after using the toilet or changing diapers, and always before eating or preparing food. Do it right – hum Happy Birthday, Twinkle Twinkle, or another favorite ditty while scrubbing soap on every hand surface. Don’t touch the faucet or doorknob after washing – I’m waiting to jump back on. Keep a paper towel handy for those things. Hand sanitizers are better than nothing (at least you’ll kill some other germ buddies), but choose soap and water when possible. Always rinse fresh produce – who knows what it was irrigated with?
Norovirus – When You Are Sick
Despite your best efforts, I’ll still get you sooner or later. I’m pretty clever, and all it takes is one careless food preparer. Just keep the fluids up and you’ll be better soon. Young kids get screwed up chemistry with fluid loss, so give them oral rehydration fluids like Pedialyte when available. For adults, the type of fluid doesn’t matter as much – just avoid caffeine, alcohol, and sugary things which make diarrhea worse. Watch for signs of dehydration, like dizziness when standing, dry mouth, and decreased urination. Get thee to a doctor if these occur! I don’t want to kill you. It’s best to avoid medications for diarrhea or nausea unless prescribed by the doctor.
When sick, the best way to block my plan for world domination is isolation. Stick to one bathroom and one bed. Don’t share anything. Wash hands after every bathroom visit, and immediately disinfect contaminated surfaces with strong bleach solutions. Soiled clothing and linens should be washed immediately with detergent, using the longest cycle length and hottest water possible, followed by machine drying – remember, I’m a tough little bug. Wear gloves, and don’t agitate clothes (meaning don’t shake or throw them around, as opposed to getting them upset). This keeps me from flying around the room. When feeling better, go on a bleach cleaning spree.
Keep away from food preparation while sick and for several days afterwards. Don’t be a conscientious employee. Stay home a few more days and let others struggle without you (and me). Productivity will be higher with one sick employee than with many. Attention employers: paid sick days save you money in the long run if it keeps me from getting a foothold in your business!
Norovirus – Preventing Disaster Epidemics
In a disaster setting, drink only boiled or bottled water during diarrhea outbreaks. Use boiled water for hand washing, food preparation, and dish washing. Keep several bottles of bleach in your emergency stores for decontaminating surfaces touched by outsiders (or sick insiders). Try to avoid areas where others congregate during outbreaks.
For disaster workers or volunteers, your personal hygiene can make or break it for literally thousands. Wash your hands frequently. Don’t work during or for several days after diarrheal illness. No one is indispensable enough to warrant spreading my noros around a disaster scene. In shelters, health facilities, and food/water preparation or distribution areas, learn and practice procedures for controlling disease transmission. Shelters should have plans to isolate infected patients with separate sleeping areas and toilets. If written procedures aren’t available, listen for alarm bells in your head – this may not be a safe setting for disaster victims or for you, although my virus compatriots and I will love it.
Have I convinced you that norovirus is the perfect virus – nearly indestructible with a well thought out plan for conquering the world? Watch for us – we’ll be coming to hands near you soon!
Sheila Sund, M.D.