Wednesday, October 3, 2018

One of these things doesn't belong

Norovirus
Flu virus
Rhinovirus (common cold)
Ebola virus
If you guessed the flu virus you would have been correct from the disinfecting/sanitizing standpoint.

The flu virus is an "enveloped" virus and is 100-to-1000 times easier to kill or inactivate than "non-enveloped" virus.

The disinfecting protocols for non-enveloped virus like norovirus on clean surfaces are 10 minutes of contact with beach-and-water solution. Many of the disinfecting agents that flatten the flu virus bounce off of non-enveloped virus. From a practical standpoint most people dealing with noro opt for disposable protective gear and incineration rather than the long wait times.

One reason that people opt for incineration is that norovirus contaminated surfaces are never "clean". Folks, we are talking puke and feces. The organic loading and contaminated particulates pose huge challenges to the disinfecting agent.

Flu, by contrast, is typically spread by tiny, aerosol particles. They splat on surface or get smudged on surfaces like door handles. The virus is very exposed to UV light or any common disinfecting material. Disinfecting materials disrupt the fatty-coating on the flu virus and it is game-over for the bad-guy.


The casual ease with which flu virus can be killed outside the body lulls people into a false sense of security.


Let's exercise a little bit of logic here. It takes ten minutes of contact time to kill nonenveloped virus like norovirus and Ebola. In ten minutes that mist will either have blown away or settled down. Ergo, the mist around the operator is laden with infective virus even if the surface was nominally "clean", that is, no particles, dried body fluids or chunks of tissue/vomitus/feces.

Norovirus is a good proxy for the scope of a potential Ebola event in the United States. Both noro and Ebola spew astronomical numbers of virus in sticky-icky media. They are both communicable before the carrier is symptomatic.

One major difference is that a noro patient is more likely to self-quarantine. They are far more likely to stay home and tough it out. Ebola? Nearly everybody I know would bee-line to the Emergency Room if they looked in the mirror and noticed they were bleeding out of their eyeballs.

The CDC estimates 20 million cases of acute noro per year in the United States. No estimate is made of the number of sub-acute cases.

20 million-to-40 million Ebola patients per year is a defensible, first-order estimate in the event that Ebola establishes a toe-hold in North America.

No comments:

Post a Comment