eli5: Why can’t our bodies defend against amoeba?


I’ve heard of brain-eating amoeba which is some scary shit.

In: 8

5 Answers

Anonymous 0 Comments

In general our bodies can defend against amoeba, but the brain-eating one works a bit differently: in layman’s terms, it’s not the amoeba actually doing the damage, but your own immune system, in trying to fight it more and more aggressively, ends up corroding your brains

Anonymous 0 Comments

I had entamoeba hystolica a few years ago and it wasn’t fun. I’m so thankful for antibiotics.
When the antibodies attach to the amoeba, the amoeba just sheds the affected area and grows a new one later. Your body tries to get rid of it but flushing everything out which causes dehydration.
I met a WW2 vet that told me he also had gotten amoebas in Italy. He woke up 4 weeks later at a hospital and the first thing he heard was the guy next to him saying “look, he is alive”.

Anonymous 0 Comments

Our immune system can deal with almost all infections, including amoeba, pretty well.

The problem is that the active cells in our adaptive immune system are amazingly powerful, and as a result incredibly dangerous. For example, Neutrophils are like hand grenades: when they are activated they start accumulating bubbles of Hydrogen Peroxide inside themselves, then when they locate what they think is a bad guy they literally explode and take out a good chunk of tissue. Macrophages are like Godzilla: when activated they grow to a huge size and rampage around swallowing and digesting almost anything they can find.

Letting monsters like this lose in the brain, full of extremely intricate and delicate nerve cells, would be a disaster, so there’s a special blood-brain barrier which keeps them completely out of the nervous system.


So the brain is now safe from accidental attack by your own immune system, but will clearly be very vulnerable to infection if some bad guy does somehow manage to slip in there.

Anonymous 0 Comments

Most of us can, and most of us do defend against all kinds of attacks every day.

Bacteria, parasites, viruses, fungus, and a whole host of microorganisms are often called “opportunistic” meaning that they are common, but when a person’s defences are weak, or if they are exposed to a new attack their body is not prepared for, the attacker might win.

This amoeba is a big risk because our brains are very “soft targets”.

A brain infection can kill us.

Our immune response (fever, swelling) can also kill us.

Anonymous 0 Comments

our bodies defend, but it gets desperate without results and starts throwing everything they can at the amoeba, hurting itself