Chagas disease

Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. It is classified as a neglected tropical disease resulting from complex social and environmental determinants. The parasite primarily infects humans and other mammals through vector-borne transmission, though multiple additional routes contribute to its spread. The disease is curable if treatment is initiated during the early acute phase, highlighting the importance of timely diagnosis.

Chagas disease manifests in two distinct phases. The acute phase lasts approximately two months, during which parasites circulate at high levels in the blood; symptoms may include fever, headache, enlarged lymph glands, pallor, muscle pain, cough, difficulty breathing, liver enlargement, and generalized body swelling, though many cases remain asymptomatic. Characteristic visible signs include a skin lesion called a chagoma or Romaña sign (purplish swelling of the eyelid). The chronic phase follows, with parasites sequestered primarily in cardiac and digestive muscle tissue. Between 10-30 years after initial infection, up to 45% of chronically infected individuals develop cardiac disease leading to heart failure, while up to 21% experience digestive complications including megaesophagus and megacolon. Mortality rates over a 10-year period range from 9-85%, with death typically resulting from arrhythmias, heart failure, or stroke.

Chagas disease is endemic across 21 continental Latin American countries, though its epidemiological pattern has shifted from rural to predominantly urban transmission due to population mobility and urbanization. An estimated 6-8 million people are infected globally, with over 75 million at continued risk. The disease has spread beyond the Americas to Canada, the United States, numerous European countries, and parts of Africa, the Eastern Mediterranean, and Western Pacific regions. Vector and wild reservoir distribution extends from the United States to Argentina and Chile (latitudes 46°N to 46°S), with more than 150 triatomine bug species and over 100 mammal species maintaining T. cruzi in nature. Opossums are among the most important reservoirs. An estimated 10,000 or more deaths occur annually from clinical manifestations of Chagas disease.

Primary transmission occurs when humans come into contact with the feces and/or urine of infected blood-sucking triatomine bugs (kissing bugs), typically through inadvertent contamination of bite wounds, mucous membranes, or skin breaks. Foodborne oral transmission occurs through consumption of contaminated food or beverages. Globally, congenital transmission during pregnancy and childbirth has become the most common route. Additional transmission pathways include blood and blood product transfusion, organ transplantation, and laboratory accidents. The vector distribution spans the Americas, with primary human-dwelling species including Triatoma infestans, Rhodnius prolixus, Triatoma dimidiata, and Panstrongylus megistus.

Populations at highest risk include residents of endemic areas in Latin America, particularly those living in poorly constructed housing where triatomine bugs thrive. Migrants from endemic regions now residing in non-endemic countries represent a significant affected population. Immunocompromised individuals face elevated risk of severe disease manifestations and reactivation. The disease disproportionately affects populations characterized by poverty and social exclusion, reflecting its classification as a neglected tropical disease.

Prevention strategies focus on eliminating triatomine bugs through improved housing conditions and insecticide application, as these vectors typically inhabit wall or roof cracks of poorly constructed homes in rural or suburban areas. Blood donation screening represents a critical control measure to prevent transfusion-associated transmission. Public health education about exposure risks and early treatment seeking is essential. Treatment initiated during the acute phase can cure the infection, underscoring the importance of early diagnosis and intervention.

Surveillance requires awareness of the disease's changing geographic distribution beyond traditional endemic areas. Diagnosis during the acute phase relies on detecting parasites in blood through microscopic examination or polymerase chain reaction, while chronic infection is identified by detecting T. cruzi antibodies. Reactivation can occur during immunosuppression from older age, HIV/AIDS, cancer, or immunosuppressive therapies, requiring heightened clinical vigilance in these populations. The social stigma associated with Chagas disease may affect health-seeking behavior and screening participation.

1. 1 WHO Health Topics. Chagas disease (American trypanosomiasis).
2. 2 WHO Fact Sheet. Detail.
3. 3 WHO Q&A. Chagas disease (American trypanosomiasis).
4. 4 Wikidata. Chagas disease.
5. 5 Wikipedia. Chagas disease - Wikipedia.

ICD-10

B57

ICD-11

1F53

Total cases

0

Peak month

—

Coverage

0 reporting countries · —