Expert: Terry B - 3/4/2009

Question
As i follow up on your last email i spend a week reading information:  But i am getting alot of different answer, here is my finding:



I read in many post from MR SOWAOSKY that hiv virus even in wet environment would last only a few minute and that the hiv will die, i also read in many post in the thebody.com including a post from Lynne Gabriel that a case serenio where a blood drop in to a tower, the hiv would probably last few sec, i also read in many post that hiv does not last for a few minute. After reading so many post i feel i was very safe than yesterday i come to a international journal from Mariette Correa and david Gisselquist,
http://www.rsm.ac.uk/media/downloads/jsa06-11gisselquist743-748.pdf

In this journal is states that:
Doctors reported they had become more conscious
of safe and unsafe practices due to the HIV
epidemic. However, most doctors we spoke with
mistakenly believed that HIV survives for only
seconds to minutes outside the body. Similarly,
they believe the risk to transmit HIV through an
injection with contaminated equipment is very low.
We found that the general public has similar
misconceptions. For example, FSWs in a focus
group discussion in Karnataka (mentioned above)
were surprised to hear that HIV can survive for
hours or weeks outside the body. Nevertheless,
patient concern for safety appears to be one factor
behind the shift towards disposable syringes. For
example, one doctor reported that FSWs insisted he
use disposable syringes and needles to give them
injections

That make me worry and i hope you can explain which one is the correct one: does hiv survive outside it's host for that long, or in my case a drop of fresh stain on the pant is enough to die after 5-7 minute?

Thank You!


Answer
Dear Martin:

Peace.  Sorry for delay, I was out of town at a funeral for nearly a week and just returned.  Simply, HIV is a retrovirus that needs bond with the genetic material in blood cells to make copies of itself.  If cells dry, they fall apart, and with them the genetic instructions.

All fluids dry from the outside in.   If a cell infected with HIV is frozen, somehow protected from desiccation, or otherwise retained intact, the potential for infectivity persists.  In what you describe I don't see such protection of the cell and retention of fluid.  

So... short answer, there are cases where HIV can exist outside the body but most of the time, drying is the action that renders the virus unable to reproduce or infect.  

I hope that makes it clearer; retaining intact cells within a syringe or needle can spread the virus with injection, in part because an injection bypasses the skin and mucous membranes.  For a surface contact with a non-fluid sample, there seems no significant risk.

Best to you and yours,

Terry