Monthly Archives: December 2009

A Chagas’ Disease Primer: Part 3

If you wish to read the Chagas’ Disease primer in order, click here to go to Part 1 and follow the links.

Life Cycle of Trypanosoma cruzi
Below is the life cycle of T. cruzi.

Countless medical and veterinary students have been up late nights cursing life cycles, trying to remember the difference between Strongyloides stercoralis, Strongyles vulgaris, and Aelurostrongylus abstrusus . Parasitologists (at least male, heterosexual parasitologists), however, would rather look at complicated life cycles than pictures of Anita Ekberg in her prime.

The recommendation of this blog is to read this and get familiar with it. You don’t need to memorize it to understand Chagas’ disease. (Click on the diagram for a larger, more legible view.)

As far as life cycles go, it’s relatively uncomplicated. Write to us if you have any questions. Thanks to the CDC for the diagram.


A Chagas’ Disease Primer: Part 2

If you wish to read the Chagas’ Disease primer in order, click here to go to Part 1 and follow the links.

OK, where were we?

Chagas’ Disease is caused by the protozoan parasite Trypanosoma cruzi, and is spread by the bite of something called the kissing or assassin bug. We compared it to malaria, another protozoan, vector-borne disease.

But whereas most vector-borne diseases are spread via the saliva of the vector (the parasite malaria, the bacterium Lyme disease, the virus Yellow Fever), Chagas’ Disease is spread by feces of the assassin bug. The bug defecates while it eats, depositing its parasite-laden feces onto the host’s skin. When the host scratches the area, rubbing the feces  into the wound made by the bite, he (or she) becomes infected.

The Assassin Bug: Approximately 2 cm. of repugnant, disease-spreading ugliness

A Chagas’ Disease Primer: Part 1

As  Chagas’ Disease is rather unknown here in the Northern Latitudes, this blog has decided that it’s time to give our readers (assuming that we have any) a good background on this malady. It’s our goal to get Chagas’ Disease–with anywhere from 8 to 15 million persons infected–the attention that it deserves. 

What is Chagas’?
Chagas’ Disease is infection with the parasite Trypanosoma cruzi. T. cruzi is a protozoan parasite, meaning it’s a single-celled eukaryotic pathogen, as opposed to the worms (like tapeworms and roundworms) and insects (like fleas, lice and ticks ) that we normally think of. Think more of malaria  ( a protist that infects the liver and red blood cells) , amoebic dysentery, or cryptosporidiosis.

Like malaria (but unlike amoebic dysentery or cryptosporidiosis), Chagas’ Disease is a vector-borne disease. The vector in Chagas’ disease is a bug, commonly known as a kissing bug (because it often bites its sleeping victims on the face) or an assassin bug (the name we clearly prefer on this blog).

Parasitic diseases generally rank highest on the gross-out scale, above viruses, bacteria, and fungal infections.While the manifestation of clinical Chagas’ Disease isn’t as outwardly repulsive as, say, Guinea worm, its mode of transmission is. Stay tuned for Part II.

Chagas’ Disease hits MSF’s Top Ten List

Every year Medecins Sans Frontieres makes a list of the year’s top humanitarian crises. I’m not sure what their criteria are, but I couldn’t agree more with the inclusion of the neglected tropical diseases. Chagas’ disease seems to be one of the more neglected of the neglected, but it’s hard to measure “neglectfulness.” Is it not knowing about the disease, or is it knowing but doing little?