With two cruise ships returning to port last week after having been boarded by the Dread Pirate Projectile Vomiting, people are once again referring to cruise ships as "floating Petri dishes." The comparison is both unfair and inaccurate, since Petri dishes don't offer options like karaoke, video slots, skeet shooting, and pool recreation, and Petri dish buffet spreads are notoriously monotonous -- usually some kind of broth and agar mix.
As the passengers return home to recover, the CDC and cruise lines go to work trying to figure out the details of this latest high-profile outbreak of norovirus, aka "the stomach flu" or "the cruise ship virus."
Those two nicknames are misleading, however, because the hallmark flu symptoms -- high fever, severe muscle aches, sore throat and dry cough -- are typically much different than norovirus's profoundly gastrointestinal symptoms. (For clarity in public health messaging, I am lobbying the CDC to rename norovirus as the "Pukes-'n-Squirts virus." No word yet.) And although it's true that norovirus can spread quickly aboard the intimate confines of a ship, "the cruise ship virus" happens to be the predominant cause of pukes-'n-squirts in land-based outbreaks. In other words, this pirate does most of its damage in port. When "it's going around" at school or in a nursing home, "it" is usually the norovirus.
In March of 2011, the CDC published an update on the science of norovirus. Historically, we've never understood this virus very well, because it's been impossible to grow in a culture -- even in a "floating Petri dish" (another way in which the slur is inaccurate). It's difficult to study what you cannot even "see," but newer technology has allowed us to document its presence and therefore investigate its behavior. Points of interest from the update include:
- This sh#t is more infectious than the mood at a Taylor Swift concert: An acutely-infected person can have as many as 100 billion viral copies in a gram of stool, and it takes as little as 18 viral copies to become ill. Virus comes out of both ends, but diarrhea is thought to be more infective than vomit.