Virus questions (4)

[Studoggie]

I am kinda sick today and I am now realizing how little I know about viruses. Here are a few questions that I have.

1. Why does it sometimes only take a day or two to get over the flu while other times it takes much longer.
2. By taking a pain reliever to reduce my fever am I doing a disservice to my body’s natural defenses?
3. Why are most viruses transmitted fairly easily while AIDS is relatively difficult to transmit.
4. Not to get stuck on AIDS, but here is a question that I have always wondered about. How can a man get AIDS through heterosexual sex. I’ve read that it is much harder for it to happen, but how is it at all possible?

Sorry I have so many different questions for one thread.

[AWB]

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[li]Either:[/li][ul][li]You’ve got a strain of flu that you’ve had before, so your body’s defenses are already primed[/li][li]Your health and defenses are generally good, so they’re stronger from the start of your sickness[/li][li]You’ve still got the flu, but you’re either asymptomatic or the symptoms aren’t very noticable[/li][/ul]
[li]Arguably yes. The fever is one of the ways your body uses to kill “germs”. It’s more effective against bacteria, IIRC, but viruses also fall to it.[/li]
But if your fever gets too high (your body keeps detecting more and more viruses, but the fever isn’t killing them off faster than they multiply), your body cells start getting killed. So a slight fever is good, a high fever is bad.

[li]HIV is a fairly fragile virus as viruses go. Outside of a body and/or bodily fluids, they die quickly. But in body-body or fluid-fluid transferrs, they survive to multiply in the new host.[/li]
So on toilet seats, the virus will die, but in syringes they’ll live.

And as to its transmitability: think of it in terms of Star Trek: HIV is an attacking alien, the Enterprise’s shields are your body’s level of defense against HIV getting a foothold.

After the first attack (first exposure to HIV), the E’s shields are down to 75%. Very survivable.

If there’s a second attack before shields are back to 100%, the shields go down to 50%.

Following attacks take the shields down to 25%, the 0%. (At this point, there’s no eliminating the virus, and it begins to multiply.)

[li]Yes, it’s harder, though not impossible. An infected female’s lubricating fluids have HIV in it. The virus can then enter through the end of the urethra, or if the male has any abrasions or sores on his penis, through these.[/li]
Male-to-partner infections are more likely to take, as more fluid is left in the partner, so the virus thrives. And if there’s blood vessels broken during coitus, the infection is aided even more.
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[Smeghead]

One other thing. “Most” viruses are not easily transmittable. It just seems that way, because those are the ones that often infect us, obviously.

Airborne viral spread (the easiest method) is actually relatively rare. Probably the most common method of spread is fecal-oral - putting something contaminated in your mouth.

[KarlGauss]

[sub]Why does it sometimes take longer to get over the flu?[/sub]
In addition to the previous answers, I’d also mention that much of the symptomatology of having a typical flu or cold stems from the body’s response to the virus, and is not directly due to the virus per se.

[sub]Is having a fever beneficial when you’ve got an infection?[/sub]
You’d certainly think so. After all, it’s been preserved through evolution. Still, there’s not a lot of evidence either way. This thread discussed the issue, and contains a link to this contemporary review (of which only the abstract is free).

[Facts_R_Us]

AWB correctly reports conventional wisdom:

4. Yes, it’s harder, though not impossible. An infected female’s lubricating fluids have HIV in it. The virus can then enter through the end of the urethra, or if the male has any abrasions or sores on his penis, through these.

Male-to-partner infections are more likely to take, as more fluid is left in the partner, so the virus thrives. And if there’s blood vessels broken during coitus, the infection is aided even more.

But conventional wisdom may not be the truth. From
http://dailynews.yahoo.com/h/ap/20010208/hl/aids_sex_act_2.html

-The risk that an HIV-infected woman will transmit the virus to an uninfected man is one in 454. For an infected man to an uninfected woman, it is one in 769. This difference is not large enough to be statistically meaningful, and many have assumed that HIV spreads more readily from men to women than vice versa.

it appears that female-to-male transmission occurs more readily than male-to-female transmission, although the small number of couples studied meant that the observed difference was not statistically significant.

Aside - I guess I’m glad they did that study and obtained the information, and in Africa, there’s no way these people would have gotten treated anyway, but in my mind, there are serious ethical problems in just observing couples give each other HIV when it is almost invariably a fatal disease dus to lack of treatment options.