WILTIMS #207: A pox upon you!

Herpes is a word that has morphed many times in my mind. In early sex-ed classes, I associated it with the barrage of sexually transmitted infections that the teachers accost your senses with (hopefully just sight), like gonorrhea, chlamydia, and syphilis. Then in high school, as with so many "facts," I learned that it wasn't quite so simple: herpes is also the cause for cold sores. It was a great conversation piece for all those herpes conversations that came up...

But as I experienced more and more of biology and medicine, both in high school and undergrad, I heard the word herpes come up over and over with all manner of seemingly unrelated illnesses. I had kind of accepted that it must be some broad term that isn't used by the general public. Turns out, I wasn't far off!

TIL: Herpesviruses are a broad family of viruses that include many disease-causing bugs of which you may have heard. There are eight types of human herpesvirus (HHV):

1. cold sores
2. genital sores
3. chicken pox/shingles
4. Epstein Barr (causes mono and several lymphomas)
5. cytomegalovirus (usually asymptomatic in the immunocompetent)
6. roseola (aka "sixth disease," one of the principle rash-causing diseases in infants)
7. also causes roseola
8. Kaposi sarcoma (used to be super rare, until the rise of AIDS)

And don't think that it's that simple, either. Type 1 (cold sores) can be found on the genitals and type 2 (STD) can cause cold sores (this cross-contamination shouldn't be too surprising given some common sexual practices). Furthermore, given the opportunity, either of the above can cause systemic infections including viral meningitis.

A one-dermatome rash caused by shingles (HHV-3)

Zoster, as in the varicella-zoster virus that causes chickenpox and shingles, means belt. It is used to describe the shingles form of the infection because of the telltale belt-like rash often seen in symptomatic patients. Herpes often sits latently in nerves throughout the body. When the HHV-3 becomes reactivated it will cause a rash throughout the area innervated by that one nerve. This leads to some anatomically interesting rashes that only affect one dermatome (the area serviced by one spinal nerve segment).

Poxviruses are a broad classification of viruses that include smallpox (as well as cowpox, monkeypox, etc) and moluscum contagiosum. By the way, unlike cowpox and monkeypox which are carried by and contracted from those respective animals, chicken pox has no connection with chickens. In fact chickens are immune to chickenpox. It is thought that the name cropped up as a way of indicating how mild the disease is compared to the better known pox, smallpox.

It was weird talking about smallpox today, because the last known diagnosis of the disease was in 1977. And it's kinda sad that the only reason we learn about it is for in the event of a bioterrorist attack.