Tried to help stop a fight, received a bite for my trouble

Hello doctors,
I am a long time reader of your forum and have posted my concerns twice. Both times a received amazing advice and I am greatly appreciative. Two nights ago I was attempting to stop an aquaintence from fighting a friend of mine. In the process of freeing himself from my grasp he bit my arm. I am always concerned about HIV and Hepatitis so once this person was calm I asked if he had been tested for either diseases recently and he responded that he was tested about two or three years ago and was negative. My arm did not appear to have any broken skin or blood but was red and I did notice one small pinpoint spot of redness. This one spot did have a very small line of redness around it but after close examination I could not conclude whether or not this redness was a very small cut, a small sore, or a small petechia.
What worries me also about this biter is that he often does dip/chewing tobacco which I understand contains small amounts of fiberglass to cause small cuts in the persons mucosa to increase tobacco delivery to the bloodstream.
My concerns/questions are...
1) If I cannot confirm that my skin was cut, would this indicate that any damage to my skins was not severe enough to allow HIV or Hep infection?
2) Would using this tobacco product increase the likelihood of this person having cuts or blood in his mouth that are not visible to the naked eye?
3) This person refused to get tested after the bite; should I fear he is infected and see a doctor about PEP? I was told that he does in fact sleep with a lot of girls. I have been very responsible about sex and hooking up since my last posts. I would be inconsolable if I caught it this way after all my previous worry. Thank you in advance for your expertise!

[H. Hunter Handsfield, M.D.]

Welcome back to the forum. Bottom line:  no risk, no worry.

HIV infection during a fight, by biting or other blood contact (e.g. a tooth cut on a knuckle or other blood exposure) is one of those theoretical exposures that could result in transmission but rarely does.  Because of the theoretical possibility, such exposures are routinely listed by various public health agencies like CDC.  However, to my knowledge there are virtually no reported transmissions by such exposures; if it occurs, it is exceedingly rare.  And certainly it can't happen by a bite that doesn't even break the skin.  To your questions:

1) Without an overt, bleeding cut, there was no risk.

2) There is no reason to suspect tobacco use would make any difference.

3) You definitely should not have PEP and probably couldn't find a doctor or clinic willing to prescribe it.  Maybe if the skin had been broken AND if your friend were at obvious high risk for HIV (e.g., if he is gay or an injection drug user), but certainly not in the circumstances you describe.

I hope this helps.  Regards--  HHH, MD

[Scaredd12345]

Thank you for your immediate response. I have just one last HIV concern to address. I had one night of unprotected sex with a girl I met. We had sex 3 times that night for a total of no more that 15 minutes total. This girl is very promiscuous and was cheating on her boyfriend with me. 5 weeks after the encounter she had an HIVantibody test that was non reactive and I had one 7 weeks after the encounter that was non reactive.
I'm starting a new and very serious relationship with another girl now and would just like to be sure that with these two results that there us no chance if infection.
My question is, is it possible that this girl was in the window period when we had sex and was infective 5 weeks prior to her negative result?
I know this question may seem extreme but I would really just love to have all my fears set aside before starting a new relationship. Thank you so much for your continuing help!!!

[H. Hunter Handsfield, M.D.]

No, there is no realistic possibility that your casual partner was in the window period.  Could it theoretically be the case?  Sure.  You could also be hit by a meteorite someday.  The odds probably are about the same.

[Scaredd12345]

Thanks again!