Wednesday, May 13, 2009

Chagas Disease

I recently collected an insect from the family Reduviidae, or assassin bugs, ambush bugs, and thread-legged bugs. Why is this medically relevant? Insects of the genus Triatoma, or bloodsucking cone noses, are the vector for Trypanosoma cruzi, the parasite which causes Chagas disease. It is found in South America and Mexico, and cases of Chagas disease have occurred along the southern border of the United States. The insect likes to hide in thatched hut roofs during the day and then emerges at night to feed on human blood. It is approximately 3 cm long. The insect transmits the virus through its feces, not its bite, however scratching a bite can contaminate it with the feces, and thus the parasite.

T. cruzi can also be transmitted via contaminated food, blood or organ transplants, and from mother to fetus. The disease progresses initially with swelling at the site of infection, if from a bite, and fatigue, fever, rash, headache, vomiting, etc. The most telling acute symptom is RomaƱa's sign: swelling of the eyelid on the side closest to the bug bite. Immunocompromised individuals or children can die from inflammation of the meninges (meningitis) or heart muscles (myocarditis) in the acute phase. The illness then proceeds to the chronic phase if untreated, and its eventual symptoms include heart disease and intestinal malformation. It is estimated that 8-11 million people are living with Chagas disease, most without knowledge of it because the acute symptoms are short-lasting and can be falsely attributed to other medical problems. It is now routine to test all donated blood for Chagas disease in addition to other blood-born diseases. There is no vaccine or drug to use as a preventative measure, so the only guideline is to avoid poorly constructed housing and to use bug nets and insecticides.


  1. Such a dangerous bug! :) how have you obtained the specimen?

  2. That's not the insect I collected, the insect I collected is on my insect blog, and is Rhynocoris ventralis, and it is not a member of the genus Triatoma.