Expert: Terry B - 1/27/2009

Question
Dear Terry B
I am asking this question as I am very anxious about HIV infection, and there is a lot of contradicting information on the internet about this issue.
Last weekend, I was sitting with a friend's friend drinking with our feet in a childrens inflatable mini pool, the water was about ankle deep, and was filled with river or sea water, I cant remember which. Anyway, I noticed that the other person was bleeding from their knee, and some blood was trickling down their leg. I am sure that atleast a few drops of blood would have gotten into the water. At the time, i had peeling skin between my toes, and an old blister on the back of my heel. The blister looked almost healed, no traces of blood, just open skin with healthy looking skin underneath. I would have only been in the water for 10 minutes after noticing this. If they were infected with HIV, how likely is the risk of transmission?

Cheers.

Answer
Dear Rob:

Peace and all good things.  Human Immunodeficiency Virus - the virus which causes AIDS - is not easily transmitted.  The easiest way to assess risk is with an understanding of HIV and the factors that contribute to - or detract from - risk.   The factors include:

Route: What is the proximity of a cell containing HIV to the bloodstream of the person exposed?  Understanding that skin and mucous membranes are the body's barrier against infection, what is the condition of that barrier?  Thus sharing of needles and injection use equipment is of highest risk as they bypass this barrier; spill of semen, blood, or vaginal secretions on intact skin is of low risk.  In the cases of a healing wound, the quality and integrity of the skin (where along in the healing process) decreases the risk as the wound heals.  "New skin" as described would provide a significant barrier to infection.  An actively bleeding wound or infection (lesion, sore) such as a Sexually Transmitted Infection places you at greater risk.

Concentration of HIV in the fluid:  The amount of virus found in the blood is highest early on in infection, when the virus is replicating without being impeded by initial recognition and suppression by the immune system, and again late in AIDS, when the virus has defeated the body's ability to fight the virus.  Since you don't know the status of the person with whom you shared the pool, this doesn't help you in this case.

Amount of the fluid to which you are exposed:  The more fluid (blood, semen, vaginal secretions, breast milk) to which you are exposed, the greater your risk.  This is probably the largest factor in your favor in what you describe - the amount of fluid - ergo the number of intact cells containing HIV - in the water you describe is miniscule.  

These seem the most important factors in assessing your risk - more information at peer-reviewed sites (www.avert.org, www.unaids.org) or reputable sites such as www.thebody.com can provide you with broader information for your HIV awareness, and additional factors - area, duration, frequency - which seem unimportant in this situation.

To assess your HIV risk, even assuming your bleeding foot co-soaker is positive, take the low risk of your generally intact skin and lessen it by the chances of an intact cell containing HIV coming into contact with that skin and finding a 'portal of entry' into your bloodstream.  This seems to pose no significant risk - of HIV infection.  Hepatitis and other viral or bacterial pathogens are hardier and more easily transmitted.

In short, I don't see this as placing you at significant risk of HIV transmission.  Remember that even a direct exposure to HIV does not mean necessarily that a person becomes infected.

I hope this puts your mind at ease and that your further research will enlist you to the ranks of informed community resources in the battle against HIV.

Sincerely,

Terry