A Chagas’ Disease Primer: Part 6

Chronic Chagas’ Disease

This is where the problem is.
Most people won’t get signs of acute infection, so they won’t know that they are infected.
In 70% of cases, that’s fine. As far as we know, nothing will come of that.

But the other 30%, anywhere from 10 -30 years later, will go on to develop chronic Chagas’ Disease.

Let’s review. We have our  assassin bug,

Triatoma dimidiata, important vector in Mexico

which transmits the single-celled protozoan parasite, Trypanosoma cruzi (in its feces)

A T. cruzi parasite, among red blood cells on a slide

The bug poop gets rubbed into a mucous membrane (like the conjunctiva around the eye) or the bite made by the bug.
Let’s look at the life cycle again:

For those of you who care, the trypomastigote is the infective stage, that is the stage that can be passed from bug to mammal and mammal to bug. The amastigote is the stage that multiplies in tissue.

Don’t get hung up on the names. It’s just to see that different stages do different things–one goes around to infect different cells, the other works inside the cells.

Detail of above diagram

Trypomastigotes have flagella, whip-like structures that allow them to move around, amastigotes don’t. On a blood smear you can see the trypomastigotes squiggling around among the blood cells.

Amastigotes seem to like replicating in the cells of the heart’s muscle.

That is not a good thing.


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