Hello Dr Bob I apologise, but I need your help again. I'm pretty certain it is the OCD (again!) but please if you could spare a few minutes I would be very grateful.

I was at a party at the weekend with my family. There was a chocolate cake with a large serrated knife. Everyone was helping themselves to food when I heard one guy say "oh she's licked the knife - don't worry it's a South African thing!" as his girlfriend from South Africa was cutting the cake. I wasn't able to see if she had licked it or not as there were so many people in front of me. My husband then went and cut a slice of cake afterwards for himself - ignoring my worries about the knife. I thought he then washed the knife before cutting a slice each for my two children but he now disputes this. I felt sick with worry and asked the lady (in a nice way) if her boyfriend had been joking - she told me yes and that she had not licked the knife. I then checked with her boyfriend and he told me he had just been joking. I feel so stupid and small - I know people do joke but this has really got to me. They didn't know I have OCD -but I want to and need to lead a normal life.

If she had licked the knife (which I can't imagine a grown woman doing) then would there be any risk of HIV transmission to my husband and children from eating the cake cut by the same knife?

My thinking head tells me she would have cut herself badly on the serrated knife - so unlikely, but my OCD head keeps saying what if...

My thinking head tells me it was just a joke, but my OCD head keeps saying why would someone joke about this...

I'm on Prozac and waiting for therapy. I apologize again for taking up your time

Hi,

Once again your problem is OCD, not HIV. Even if someone did lick the knife, the HIV-acquisition risk from using the same knife would be nonexistent. Saliva that does not contain visible blood is not considered a transmission risk for HIV. Even with blood, if the knife was used to cut cake, the blood would be rubbed off. Also, HIV does not survive long at all outside the body. So for multiple reasons, the HIV risk you fear is an absolute impossibility. No ifs, and or buts about it. But deep down you knew that, didn't you? Of course you did.

Thanks for your donation to The Robert James Frascino AIDS Foundation (www.concertedeffort.org). It's warmly appreciated.

Good luck with your therapy. I'm confident it will help you confront and conquer these irrational fears.

Dr. Bob