Bringing norovirus under cruise control

Most readers probably never gave much thought to tissue culture, the laboratory technique where cells or tissues are grown in flasks or other containers separated from the organism of origin. One of the reasons for doing this is to grow viruses, since a virus needs a host cell to replicate. It can't "live" on its own and doesn't grow in size. It just makes a copy of itself. Dog kidney cancer cells, for example, are used to grow influenza virus in flasks that also contain nutrient medium for the dog cells. Finding the right tissue culture system for a virus is an art in itself. For many viruses there is no way to grow them at all except in the intact organism they make sick (like us). Until recently that was the case for norovirus, the nasty little bug that causes epidemic gastrointestinal outbreaks in communities, hotels and cruise ships. Indeed the latest victim of norovirus is the grand dame of cruse ships, the QE2:

The Queen Elizabeth 2 has become the 1st cruise ship in 2007 to suffer a serious outbreak of norovirus illness, with about 16 per cent of passengers sickened since the ship left Southampton, England on Tue 2 Jan 2007.

Members of the United States Centers for Disease Control and Prevention will board the ship on Fri 19 Jan 2007 in Acapulco, Mexico. So far, 263 passengers and 27 crew members have shown signs of norovirus infection, a common ailment that causes vomiting and diarrhea for 48 to 72 hours.

The Cunard Line ship is on a 106-night world cruise that included a stop in Fort Lauderdale last week. After a dockside meeting with Queen Mary 2, the 2 ships left Port Everglades on 10 Jan 2007 on separate itineraries.

Cunard spokesman Brian O'Connor said the norovirus outbreak began before the ship reached Fort Lauderdale on its trans-Atlantic trip to New York. Cases began declining after it left New York. Four passengers were still sick on Thu 18 Jan 2007, he said. O'Connor said Cunard has no plans to interrupt the QE2 world cruise for disinfection, although special cleaning rules have been followed since the outbreak began. The Queen Elizabeth 2 has become the 1st cruise ship in 2007 to suffer a serious outbreak of norovirus illness, with about 16 per cent of passengers sickened since the ship left Southampton, England on Tue 2 Jan 2007.

Members of the United States Centers for Disease Control and Prevention will board the ship on Fri 19 Jan 2007 in Acapulco, Mexico. So far, 263 passengers and 27 crew members have shown signs of norovirus infection, a common ailment that causes vomiting and diarrhea for 48 to 72 hours.

The Cunard Line ship is on a 106-night world cruise that included a stop in Fort Lauderdale last week. After a dockside meeting with Queen Mary 2, the 2 ships left Port Everglades on 10 Jan 2007 on separate itineraries.

Cunard spokesman Brian O'Connor said the norovirus outbreak began before the ship reached Fort Lauderdale on its trans-Atlantic trip to New York. Cases began declining after it left New York. Four passengers were still sick on Thu 18 Jan 2007, he said. O'Connor said Cunard has no plans to interrupt the QE2 world cruise for disinfection, although special cleaning rules have been followed since the outbreak began.(CBS4)

A norovirus infection is a very unpleasant couple of days of severe gastroenteritis (nausea, vomiting, diarrhea). The incubation period is 12 to 24 hours. It usually goes away by itself (it is "self-limiting" in infectious disease jargon), but while it is around, you'd like to check out yourself. Permanently. There are no drugs for it. You just have to wait for it to go away. Even figuring out that the culprit is a norovirus is not easy. With no animal model for the norovirus and no tissue culture technique, you mainly have to study it clinically or epidemiologically. Recently a tissue culture system using animal cells was devised, but none to answer questions about how the virus attaches and enters human cells. Now a paper in CDC's journal Emerging Infectious Diseases announces a major breakthrough, a cell culture infectivity assay for human noroviruses. As breakthroughs go, it sounds pretty dry: In Vitro Cell Culture Infectivity Assay for Human Noroviruses (Straub et al.).

The researchers devised a three dimensional tissue culture medium by growing human intestinal cells on small beads coated with collagen that are tumbled with nutrient material in a small bioreactor. Apparently there is something about the three dimensional structure of several cell types bathed in nutrient fluid that makes growing the norovirus in human cells possible. It seems to mimic human tissues and organs.

The resulting system is a first step to a cell culture assay for human noroviruses. With this tool some important work can now be done on the way the virus interacts and infects cells, how the immune system reacts to infected cells, how the virus replicates and much more. When we read scientific work about influenza or E. coli we usually don't stop to ask what kinds of technical advances made those studies possible. But it is papers like this that are the foundation for a great deal of research. This is one reason, among many, why the current funding crunch at NIH and other science agencies is so lamentable. If we don't support basic research, we have a much harder time doing the applied research most ordinary people want to see done.

Like making sure that the only cruise that makes you sick will be named Tom.

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Since people won't generally admit to not washing their hands after they use the toilet, it seems to me that the ability to track this thing is somewhat limited.

What's needed is a system of surveilance cameras in the public areas of public restrooms: One or two cameras to pick up a general view of the room, sufficient to identify faces of people as they leave the toilet cubicles and either go to the sink to wash hands or exit directly. Then a camera at each sink, that can take close-up video of the techniques people are using to wash their hands. Do they merely sprinkle some water on and shake it off? Or do they actually apply soap and do a thorough job of it? And then as they exit the WC, do they use a paper towel or some such means to prevent direct contact between hands and doorknob?

There's no need for cameras in the toilets; aside from the privacy issue (few things in life could be more objectionable, except perhaps your boss staring at your "private" parts while you pee into a cup for a routine "drug test"). We can simply assume that everyone gets poo on their hands while wiping their bottoms.

The other place for cameras is onboard the galleys in these ships, to record the hand washing behaviors of galley staff.

Yes, I'm serious about this. It ought to be a requirement on cruise ships and perhaps in other places as well. Then when people start getting sick, health authorities can pull the video tapes and get decent tracking, and try to develop correlations between the details of hand-washing behaviors and the probability of catching the damn virus.

One thing I think we'll discover is that some members of cruise crews aren't washing their own hands before preparing food. Some are probably being hired on with little in the way of training and not much more in the way of supervision.

But hey, they're in good company. Rumor has it that the anti-science crowd wants to remove half the sinks in public school restrooms and replace them with "prayer stations," on the theory that God heals all for those who have faith.

Oh, one more thing. About 40 years ago there was an article in the journal "Public Cleansing & Salvage" (Institute of Public Cleansing, UK, which since changed its name to the Institute of Wastes Management), calling for specific sanitary improvements in public WCs. In particular they called for foot-pedal operation of toilet flush valves, sink taps, and doors. Think about that for a moment. Today we have (annoying and often nonworking) "automatic" motion sensor controls on toilets, sinks, and even paper towel dispensers, but we still retain the doorknob, much to the delight of all the little bugs that make it their Grand Central Station for arrivals & departures on human hands.

So let's get rid of the damn doorknobs and replace them with foot-pedals to open the doors. It's been forty years since that article was published. Forty years.

g510: Sometimes it's hard to tell when people are serious or not, but, for the sake of argument I'll assume you are. Do you have evidence that any of these things would stop a norovirus outbreak? I don't.

Unfortunately, this is no longer just a cruise ship disease. We had a very bad outbreak up and down the east coast at Christmas and New Year's Eve, and recently 100 people at the Hilton Hotel at Dulles Airport near WDC got it. A case of this can really swamp an ED - and generally they do keep their hands pretty clean.

By gaudeamus (not verified) on 04 Feb 2007 #permalink

gaudeamus: You are quite right. It really makes me sick!

Heh. The QE2 just appeared in the SF Bay. I haven't checked the pictures yet. The old bag should have had the quarantine flag out. Courtesy of Wikipedia, that most reliable of sources: A stricken ship within 3 miles of the shore had to fly at the main mast a yellow and black flag borne quarterly from sunrise to sunset. A nicer source: http://www.crwflags.com/fotw/flags/xf~q.html

More information may be found in the Aubrey/Maturin books by Patrick O'Bryan. Be sure to read all 19 of them. Ripping stuff. After this period of study you may henceforth express anticipatory excitement with the phrase "I am with child".

By Ground Zero Homeboy (not verified) on 04 Feb 2007 #permalink

Revere: Yes, I'm serious.

We need to find a way to operationalize the variable of hand washing for purposes of investigating whether people's hand washing practices have any effect on the transmission of the virus. Asking people is about as useless as trying to prove the existence of God by taking a survey. I tend to believe hand washing practices are relevant because they are for so many other infectious illnesses. But as long as we can't collect the data accurately, we don't know whether the quick rinse is sufficient or the 30-second hot water wash is needed. Cameras in the public areas of restrooms would be a good start. Remove the damn things after the research is completed, there are too many cameras around as it is.

As for foot-pedal-operated doors, yes I'm serious about that also. And you know better than I exactly what lives on doorknobs and for how long it remains infectious.

Though frankly I am starting to tire of trying to convince the idiots in the general population not to do "fecal/oral by default" and so on. At this point I have to say that, 6.5 billion humans on a planet that can sustainably support 2 - 3 billion, will not stand; and as a result, we shouldn't pretend it's not so. The only question is how to cull the herd. At this point I say let them cull themselves and let nature do the housecleaning.

The task of public health should be to keep the institutions of a democratic and lawful society functioning, not to save individual lives or lives-in-aggregate. We can't save all those people, nor should we unless we also have a way to prevent them starving after the oil peak and the climate crisis come down. But we can save our key institutions, and we should do so because they can be rebuilt in whole after the collapse phase is over and the dust has settled.

I'm an engineer, I don't engage in snark, and for the most part I don't even recognize it when others do it. What I write here is deadly serious unless it has a smiley after it. The news lately does not have me smiling. I think we're in for a hell of a time.

g510: Well I can tell you it would be pretty hard to do the study as you indicate. What exactly would you use as an outcome for handwashing efficacy? Not to mention the privacy issues. We'd never get it past a human subjects review board (and for good reason). Maybe you could sketch out for us how vieo would answer the question whether handwashing prevents flu?

I am absolutely perplexed that in my research on Noroviruses no one-and I mean no one - mentions oral and anal sex as a method of transmission. Or are they saying it but NOT saying it? What's the deal?

going through Stockholm Arlanda airport recently, i was surprised to find the restrooms (some of the ones in the domestic terminal i transited, anyway) did not have doors, or doorknobs. they had a zigzag arrangement of opaque screens blocking view, but needing no opening whatever.

i suppose the main backdraw is needing more floorspace. worth it? who knows?

By Nomen Nescio (not verified) on 03 Jul 2007 #permalink