Chagas disease is a public health issue in Central and South America, where the triatomine bug (a type of reduviid bug) is common.
This insect is sometimes known as the kissing bug, or vampire bug, because it’s drawn to the carbon dioxide exhaled from the mouth and nose and feeds in this location during the night (when the bug is most active). It can carry the parasite Trypanosoma cruzi, which is transmitted via the bug’s feces while it’s feeding near a person’s mucous membranes. Accidental rubbing of those feces into the mouth or eyes can cause transmission. The classic sign associated with this disease is unilateral eyelid swelling resulting from acute infection, so-called Romaña’s sign. Note that other forms of transmission are possible.
Once infected, cardiac involvement takes the form of an acute phase (which is rare), followed by an intermediate/chronic phase (more common). The acute phase, which was shown in the question photos, can be mild or asymptomatic, but may also manifest with a serious (sometimes fatal) myocarditis. The chronic form is more insidious, and likely affects millions of individuals in the endemic areas. This disease manifests as a dilated cardiomyopathy, with variable apical left ventricular aneurysm formation, along with interstitial lymphoplasmacytic inflammation. The conduction system abnormalities can be significant and variable in presentation. This image, by the American Heart Association summarizes the manifestations of Chagas Cardiomyopathy. For more information, this article is recommended.
Photo credits: CDC, courtesy of James Gathany; accessed: www.cdc.gov/parasites/chagas/gen_info/vectors/index.html; credit: WHO/TDR, access: www.cdc.gov/parasites/chagas/gen_info/detailed.html; www.ahajournals.org/doi/full/10.1161/CIR.0000000000000599.
- Melanie Bois