Recent comments in /f/askscience

mrshulgin t1_j9c52ui wrote

Reply to comment by CharlesOSmith in Does evolution slow down over time? by AmTheHobo

Given your explanation, would it be fair to say that species like that are "evolving in place?"

That is, they're still actively mutating, but the mutations are "undone" in successive generations.

I know I've simplified things a lot, but is this still a serviceable explanation of the concept?

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Balthasar-Hohenheim t1_j9c3dxv wrote

Reply to comment by Space_faces in Is COVID unique in the way it affects different individuals in such different ways? by stupidrobots

Rabies is effectively a two-step infection. It can infect and propagate in your "normal" cells like any other viral infection. In this stage the infection isn't necessary lethal and the virus can remain undetected in the body for long timespans (sometimes months). The immune system can also fight the illness off during this time period, which would lead to one having antibodies without being noticably sick.

The actual rabies infection that we usually think of happens when the virus enters nerve cells. From this point the virus just jumps from one neuron to the next straight to the brain without our immune system being able to interfere. One this happens one is as good as dead.

The tricky part is that the virus can enter nerve cells at any time during the initial infection (or straight from the initial wound) and at least in theory just one viral particle doing so is enough to kill. Our immune system is simply no built to deal with this situation as it functions on the principle of "use antibodies to catch most (but not all!) viral particles and let macrophages deal with all cells that still get infected". And that last part either doesn't happen at all or too late once the virus is in the nervous system. So we have to neutralize every virus particle before that can happen, hence why one should get treatment ASAP if there is any chance of one having been infected with rabies.

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NakoL1 t1_j9c2nhd wrote

Reply to comment by Perma_frosting in Are all coals equal ? by Arks_traveler

> Charcoal is the chunks of carbon that are left over when you burn something organic

that's not very accurate. "burn" means letting something react with (di)oxygen, but charcoal is made by pyrolysis, whereby wood is heated to high temperatures with no or very little oxygen

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BirdyDevil t1_j9byxq6 wrote

Reply to Is COVID unique in the way it affects different individuals in such different ways? by stupidrobots

You can't even compare all these diseases - flu, rabies, and COVID are caused by viruses, salmonella and strep throat are bacterial infections. The similarities stop there - there are plenty of viruses that even infect bacteria. But as other people have said, no, a variety of outcomes is pretty normal with everything. It depends on your individual immune response.

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