Chagas disease

Chagas disease, or American trypanosomiasis, is a potentially life-threatening systemic illness caused by the protozoan parasite Trypanosoma cruzi ^[2][3]. It was first diagnosed in a human by Brazilian physician Carlos Ribeiro Justiniano Chagas in 1909, who also identified the parasite, its insect vectors, and key animal reservoirs ^[2]. The infection is shaped by social and environmental determinants characteristic of neglected tropical diseases, and because T. cruzi circulates among more than 150 triatomine species and over 100 mammalian reservoirs, it is not considered eradicable ^[2].

When treatment is initiated early, Chagas disease is curable, but without complete treatment and follow-up it can lead to cardiac, digestive, and neurological manifestations as well as potentially life-threatening complications ^[2]. Among those infected in Latin America, an estimated 30–40% either have or will develop cardiomyopathy, digestive megasyndromes, or both ^[1]. Oral transmission through contaminated food has been associated with more frequent severe disease and higher mortality, often producing outbreaks affecting groups of people ^[3]. In addition to biomedical consequences, the disease carries a substantial psychosocial burden, as stigma related to poverty and rural life can lead to social rejection and discourage health-seeking behaviour, including screening ^[2].

An estimated 6–8 million people are infected worldwide, with the great majority of cases historically found in 21 continental Latin American countries ^[1][2][3]. Between latitudes 46°N and 46°S, more than 150 triatomine bug species and over 100 mammalian species, including opossums as important reservoirs, maintain T. cruzi in nature ^[2]. Over 10,000 people are estimated to die each year from clinical manifestations, while approximately 75–100 million people are considered at risk of infection ^[2][3]. Originally confined to rural areas, the epidemiological pattern has shifted toward urban settings within endemic countries and toward non-endemic regions; autochthonous cases are now reported within the United States alongside Latin America, and imported cases have been documented in Canada, several European countries, and parts of Africa, the Eastern Mediterranean, and the Western Pacific ^[2][3][4]. Reported case counts are believed to underestimate the true burden because of widespread barriers to diagnosis, treatment, and care ^[5].

In endemic continental Latin America, transmission most often occurs when humans come into contact with the faeces or urine of infected blood-sucking triatomine bugs that inhabit wall or roof cracks of poorly constructed rural and suburban homes ^[3]. Triatomines typically bite exposed skin at night and defecate near the bite, allowing parasites to enter when faecal material is inadvertently smeared into the bite, another skin break, the eyes, or the mouth ^[3]. Oral transmission through food contaminated with infected triatomine faeces is increasingly recognised and can produce outbreaks with more severe outcomes ^[3][5]. Congenital transmission during pregnancy and childbirth has become the most common route globally, and infection can additionally be acquired through transfusion of infected blood or blood products, organ transplantation, and laboratory accidents ^[2][3]. Outside the Americas, triatomine bugs have been identified but none have yet been found infected with T. cruzi ^[2].

Large-scale vector control programmes and screening of blood donors have reduced Chagas disease incidence and prevalence in endemic countries ^[1]. Improved housing that eliminates wall and roof cracks where triatomines colonise are core environmental measures, and food hygiene practices help prevent oral outbreaks. Treatment with benznidazole or nifurtimox is reasonably safe and effective and is now recommended for a widened range of patients ^[1].

1. 1Rassi A Jr et al. Chagas disease. Lancet. 2010 Apr 17. PMID: 20399979. doi: 10.1016/S0140-6736(10)60061-X.PubMed: https://pubmed.ncbi.nlm.nih.gov/20399979/
2. 2World Health Organization. Chagas disease (American trypanosomiasis) [Internet]. cited 3 Sept 2026.Available from: https://www.who.int/news-room/questions-and-answers/item/chagas-disease
3. 3World Health Organization. Chagas disease (American trypanosomiasis) [Internet]. cited 3 Sept 2026.Available from: https://www.who.int/health-topics/chagas-disease
4. 4Swett MC et al. Chagas Disease: Epidemiology, Diagnosis, and Treatment. Curr Cardiol Rep. 2024 Oct. PMID: 39115799. doi: 10.1007/s11886-024-02113-7.PubMed: https://pubmed.ncbi.nlm.nih.gov/39115799/
5. 5de Sousa AS et al. Chagas disease. Lancet. 2024 Jan 13. PMID: 38071985. doi: 10.1016/S0140-6736(23)01787-7.PubMed: https://pubmed.ncbi.nlm.nih.gov/38071985/