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HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 8:16 am
by David Lever
I noticed the posting re: BAIHA. I wasn't invited, not surprising since I'm not invited anywhere sob, sob. Anyway I noticed that "The Talent" were demanding monthly DNA PCR tests or condoms. However I'm still mystified as to why this "Wonder test" did not halt or prevent the USA outbreak?
Can anyone inform me as to whether this test still requires an incubation time before the virus can be detected? If so, am I correct in saying that there is a period up to the day of the test, whereby the virus could be "cooking" and not detectable?
Another thing is if the test is the answer to all our problems, why didnt the Yanks simply re- test all the talent on the same day, (establish that none were shagging while they were waiting to be tested) and then simply allowed all the "all-clears" to carry on as of that day.
Can anybody help me on this matter? Are there any Virulogists out there?

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 9:00 am
by Dan Dares
David,

The test, even in the States, is only 99% accurate at picking up the virus after 2 months! The reason is wasn;t detected in Darren's case was that he had his regular test...a few days later he was infected withthe HIV virus and worked until his next test was due whichthen tested positive (although there was of course a chance that it may not have detected his positive status until his following test a further 3-4 weeks later.

So the tests are at least able to detect the virus after a period of time and therefore at that point hopefully help contain the spread. In the case of porn that could of course mean it has spread to many others in that short period of time.


Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 9:12 am
by MonkeyMonkey
Currently, PCR method is the most sensitive technique to detect the HIV virus and does this by "amplifying" its DNA.

The issue with all diagnostic techniques is that they are subject to sensitivity. Essentially, the PCR method will require a certain number of copies of viral DNA in the blood for it to starts amplifying (working).

Now to answer your question in a virological context:
-Male A (HIV -) has anal intercourse with Female B (HIV +).
-Male A has a porn shoot in three days following his anal intercourse session with female B.
-Male A gets HIV PCR tested (test A) on the day of the shoot, which returns an HIV- result
-Male A gets tested one week later (test b) and returns an HIV+ result

Explanation, their was not enough viral DNA in his blood for the PCR to detect in test A. As time progressed, the virus replicated, increasing viral load which in effect increases the viral DNA in his blood, producing an HIV+ result later on in test B.

Incubation times can be highly variable. In some instances, I have read that a + result has taken up 90 days to show up following infection. In other instances, less than a week. That's the problem with HIV, it's highly variable in incubation times.

But saying that, PCR is by far the most accurate HIV detection method.

I hope the above helped.

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 9:43 am
by Dan Dares
Just what I said Monkey lol

Very impressive explanation indeed...far more technical version and one that perhaps everyone should read, especially the girls considering taking up the gauntlet. It's like every other analogy that exists, yes its dangerous and yes by all means take that risk if you so desire but surely you aren't making a sound judgement on the risk if you don't understand it?

I'm sure at least some of the guys and girls think, great the person I'm working with has got a test so they are safe....nothing to worry about and to be fair the risk is still very low...but the test can be wrong even on the day you get tested because (as monkey say) the test simply doesn't have enough of the virus in your blood sample for it to be able to give a positive result.

In the world before monkey, chaos reigned!


Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 10:41 am
by David Lever
May I refer to you in future as "Professor Monkey?", thanks for the explanation,

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 10:56 am
by David Lever
Another question, does the virus replicate itself at different rates in different people? So that in a very healthy person with a strong immune system, the replication would be slower and take longer to detect than say in an unhealthy person. If so, maybe a healthy person could carry the virus for longer and infect more people.

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 11:11 am
by MonkeyMonkey
"Another question, does the virus replicate itself at different rates in different people? So that in a very healthy person with a strong immune system, the replication would be slower and take longer to detect than say in an unhealthy person. If so, maybe a healthy person could carry the virus for longer and infect more people."


I'll try and make this as easy to understand as possible:

1. A strong immune system means a person has the "molecular machinery" to fight an infection (whether it be viral, bacterial or fungal) at an efficency great enough to slow down or kill off the invading pathogen (thing that is infecting the human body).

2. A strong immune system does not slow down the rate of viral replication; a strong immune system in the case of HIV slows down the internal spreading of the HIV virus.

Therefore, a strong immune system slows the spreading of HIV in the body by making it's life difficult. This is done by the bodily production of various immune reactions such as the production of antibodies, chemicals (cytokines and interleukins) and targetting immune cells (blood cells that defend the human body) against them.

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 11:17 am
by MonkeyMonkey
I forgot to mention:

yes, a person who is more efficient at fighting HIV may make him/her an "HIV -" person for longer, theoretically making it possible for him/her to pass the virus onto other people due to their HIV- test results.

That is what makes HIV such a health risk. Having unprotected sex, whether it be vaginal or anal increases this transmission risk significantly and is why people liken unprotected sex to russian roullette.

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 11:53 am
by marcusallen
Monkey:
It is great to hear from someone like yourself.
You should have been invited to the ill-fated meeting last week.

If ever there should be another one - properly organised, I for one would greatly appreciate your presence and wherever you live, I will personally pay your expenses etc. if you would care to attend.

Re: HIV/PCR test, why didn't it stop outbreak in USA

Posted: Sat May 08, 2004 12:01 pm
by ArchiPoet


thanks for your concise & understandable elucidations
( for my limited English too)

and there are these single cases of definitely HIV+ infected people
who never got AIDS til now or have got AIDS very late after XX years.
naturally off topic regarding the actual discussion.
but it shows how complex the complete HIV/AIDS situation is.

AP