Ms. Stevens is a 32-year-old humanitarian aid worker. She recently returned to the United States after spending a month volunteering in rural Guatemala, where she was assisting with community housing construction. She reports having had multiple insect bites during her stay and occasional insects in her sleeping quarters. Six months after returning to the U.S., she developed intermittent low-grade fevers, malaise, and mild right eyelid swelling.

Chagas disease—also called American trypanosomiasis—is a potentially life‑threatening infection caused by the parasite Trypanosoma cruzi. The parasite is transmitted primarily through contact with an infected “kissing bug.” Transmission occurs when an infected bug feeds at night and defecates near the bite.

The bitten individual scratches or rubs the bite site and enables the parasites to enter the skin, or the eyes if rubbed. Other transmission routes include congenital (mother‑to‑fetus), blood transfusion, organ transplantation, laboratory accidents, and foodborne outbreaks from contaminated juices or foods. Illness has an acute phase that is often mild or asymptomatic and a chronic phase that can manifest decades later with a variety of cardiac and gastrointestinal symptoms.

Global and U.S. epidemiology

WHO map of global Chagas case distribution (based on […]