Some public health agencies have reported that it may be possible to contract HIV by sharing a crack pipe. Apparently, smoking crack with a homemade crack pipe can cause burns or sores on the lips, which may lead to transmission of diseases between crack users who have burns or sores. I think herpes and hepatitis are the major concerns, but it’s been theorized that HIV might be transmitted in this way as well. For this reason, some public health agencies are distributing, or planning to distribute, crack pipes to those who smoke crack. By discouraging sharing and providing the users with crack pipes that are less likely to cause burns or sores, they hope to reduce transmission of these diseases among crack users. Unfortunately, people who smoke crack tend to also use needles and have unprotected sex.
Is the risk of Aids Xmission through oral or anal sex as great as it is for vaginal sex?
Wow, DocCathode, thanks for the vote of confidence! Yes, I am an ornithologist who works in arboviral research at Mosquito Research and Control in the Entomology department at Rutgers. I’ve written about this before, but I’ll be happy to do so again because I think it’s not really obvious without a certain understanding of mosquito form and function.
Mosquitoes don’t transmit the HIV virus for several reasons. First, mechanically, they do not act as a syringe. Blood does NOT get pulled in and pumped out with saliva. Bloodmeals move through the mosquito in a one-way flow. It does this because there are actually two tubes created from stylets that make up the proboscis (the stinger thingy- heh, this website used “stinger thingy” too), The picture shows the labrum sheath that covers the two tubes, and this sheath gets pushed back when the mosquito drills for a capillary. Saliva flows out through one of the tubes, and blood is pumped into the mosquito by the other tube. Blood is not injected into the host (hey, she needs the proteins from the blood to develop her eggs).
The bloodmeal is taken into the midgut of the mosquito. There, it’s quickly broken down into components that the mosquito can use for egg development. Now, this is where it becomes “make it or break it” time for diseases and insect vectors. A virus or other pathogen can easily be destroyed by the mosquito’s digestive enzymes. Some pathogens are too much for the mosquito as with certain filarial worms, which reproduce to the extent that the mosquito dies. HIV is a delicate flower as far as the mosquito stomach is concerned, and it is easily consumed by enxymes.
But, suppose some virus remains in the midgut. In order to get out of the mosquito, the virus must be transported by saliva into a host’s blood stream. But to get to the salivary glands, the virus must penetrate the lining of the midgut - a formidable task for many viruses. HIV does not pass easily through the lining of the midgut. (And for viruses that do, such as West Nile - a true arbovirus - the ability to pass varies from species to species of mosquitoes. Vector competency is based on this and for mosquitoes with low competency will be far less likely to complete the transmission cycle since the virus does not pass the lining easily.)
HIV has not evolved with an insect vector - unlike arboviruses, it has not evolved machaisms to exploit the midgut physioloogy of the mosquito. But HIV doesn’t “need” to. The routes it uses are depressingly all too effective.
RingOfFireI am not a medical doctor (Qadgop The Mercotan is, but a layman can handle this one).
Anal sex is riskier than vaginal. Among other things, rectal tissue is more likely to tear.
Oral sex is less risky than penis-in-vagina sex. However, there is still a risk. Condoms should be used for fellatio. Dental dams should be used during cunnilingus.
Brachyrhynchos This is why I love the SDMB. Whenever we have a thread about science, people with degrees in relevant areas show up.
Hey, I’m here to learn and fight Ignorance, just like all of you. My point was that research and evidence is not always 100%. That’s basically what I was trying to point out.
Yes, I “think”, just like research and evidence “may” and/or “suggest”.
Sorry, I didn’t know that it was a proboscis.
Maybe this short time is long enough?
And yes, I understand that HIV may not last long in a mosquito, and also that it cannot transmit after having been consumed and digested. I’m talking about a skeeter that picks up HIV, maybe is swatted (before digestion?), and seconds later lands on someone else. To say that it is impossible to give to someone else is ridiculous (even if the proboscis is a one-way street, maybe it can break?). Ok, so it’s never happened, and it’s likely that it won’t, but to say that it’s damn right impossible? That’s all I’m auguring.
I’m not paranoid, and yes it may be a “groundless fear”. I know that it is unlikely. And I’m not walking around in a bio-suit or anything…
Let’s see, on the one side we have brachyrhynchos, an expert on viral transmission and disease vectors, explaining in great detail why transmitting HIV through mosquitos is so statistically unlikely that use of the word “impossible” is warranted.
On the other hand, we have ParentalAdvisory, who has no known scientific or educational credentials of any kind, positing a sequence of events so statistically unlikely that again, the word “impossible” seems appropriate.
Add to that the fact that in more than 20 years of the AIDS epidemic there has never been a single documented case of HIV transmission through mosquito bites and PA’s claim that she is interested in fighting ignorance becomes highly suspect. Her theory on HIV transmission ranks right up there with Eddie Murphy’s “what if your girlfriend gives her gay friend a peck and comes home with the AIDS on her lips?”
With all due respect, PA, you are 100% wrong in asserting that mosquito bites are a possible vector for HIV transmission and all of your “research isn’t 100%” protestations are pointless. Please stop spreading ignorance.
To be fair Otto, the OP did also ask which method of infection from a list was most likely. The only other one mentioned, and discounted, has been a contaminated toilet seat. PA did not suggest a mossi bite was likely, just not impossible.
I should have clarified; the dildo was used in two seperate events, not mutually. There was an undetermined amount of time between when the first woman used it and the second one did.
I’ve heard of Hep C being transmitted this way. Why is it so easy for the Hep virus to travel this way but not HIV?
The statistical likelihood of HIV transmission from any of the methods listed in the OP is so close to zero that calling it zero is appropriate.
Because Hep C and HIV are different. They’re not the same. What applies to one doesn’t necessarily apply to the other!
Seriously, though, a fairly high number of virus particles are required to transmit HIV, and it’s rather fragile in the air. If Hep C can pass this way, those things are probably not true of that pathogen.
Evidence and research are almost never 100%. I cannot be one hundred percent sure that the sun will rise tommorow.
However thousands of years of records suggest that the sun will rise tomorrow, most likely in the east.
I’m no entomologist, but I suspect that this is an important distinction. The proboscis is the shnozz/mouth tube. The stinger is the needle thingy that pumps owie juice into prey or enemies.
The phrase is downright.
Second, nothing is impossible! Not if you can imagine it! That’s what being a scientist is all about! Seriously, according to some theories of physics, it’s not impossible that my laptop will spontaneously teleport to one of the moons of Jupiter. It is however, extremely and exceedingly improbable. The possibility is so unbelievably low, we can effectively treat it as zero.
This seems to contradict the fact that the virus does not live long outside of the body. I thought it died within seconds of exposure to air.
QtM,
Could you please explain that to me? I had a friend in college try to explain this to me, and I never quite understood.
“You need a significant viral load to acquire the HIV virus.”
Ok… so if you get a trivially small quantity of the HIV virus, it fails to ever become a population? What precisely happens?
Seconds seems unlikely; a virus in a droplet of liquid blood is only a little more exposed than one inside the bloodstream. Although the story related by Freejooky seems to imply that there was an extended period of time.
I think this thread has got hung up on semantics; it would appear that, to a statistician, ‘impossible’ means something slightly different than it does to a layman, for whom it is often an absolute term.
Suppose, for example; A mosquito partially feeds on an HIV-positive person with a high viral load and is brushed away, then it immediately alights on an uninfected person, begins feeding, but is squashed. There must be the ever-so-slightest possibility that the act of squashing the mosquito could inject some of the previously-ingested blood, along with still-living HIV into the bloodstream of the uninfected person. A mosquito ingests a greater amount of blood than is typically left behind on a hypodermic needle, so there could be enough blood present to present a risk of infection.
Now of course you’re all shaking your heads at this point and I’m not trying to argue that this is in any way likely at all, just that it can’t be logically impossible - a different thing from being statistically so very unlikely as to be considered ‘impossible’.
[QUOTE=Otto]
The statistical likelihood of HIV transmission from any of the methods listed in the OP is so close to zero…
I totally agree…
Until I read this.
Like I said, it’s just that statisticians have a different definition of ‘impossible’ (so extremely unlikely that the possiblity can be ignored) to the one you find in most dictionaries (Logically incapable of occurring). I know which definition I prefer.