Mechanisms of Chronic Infections

[Robin Colgrove]

Excellent topic!

I need to get thoughts and references together to write at length but
right off let me just compare a few human viruses and mention some
other chronic infections:

1) Herpesviridae
 The classic chronic-latent infections, HSV, Varicella, CMV
 which manage to set up a semi-dormant state in longlived 
 cells with expression of only a limited subset of latency genes.
 Now with Human Herpesviruses 1-8 (!) there are interesting
 similarities and differences between them (e.g KSHSV)

2) Retroviridae
 HIV, SIV, HTLV, etc. which maintain both latent infection
 and persistent active infection.

3) Hepatitis B
 A "retroposon" without a proviral form also with latent,
 persistent and chronic active forms.

4) HCV
 To my knowledge the only chronic human RNA virus infection.
 How it does this has long been an interesting mystery to me.

5) HPV
 Warts, cervical ca

6) JK
 Papovaviral cause (?) of PML in AIDS

7) Others? Veterinary examples?

Also, compare with mechanisms of non-viral persistence:

protected sites: prostate, sinus
persistent intracellular infection: chlamydia, malaria, leishmania
relapsing latent infection: TB, leprosy, syphillus, lyme oddballs:
helicobacter, bartonella

and a zillion more.
Obviously this is way too big a topic for one post but if people will
do little pieces within their specialties, we could run this out
pretty far. I could do Hep B or HIV. Any takers?

robin colgrove
Division of Infectious Diseases
Beth Israel Deaconess Medical Center
Harvard School of Medicine