The epidemiology of Chagas disease in the Americas

Abstract

Chagas disease is a complex parasitic zoonosis that still threatens public health across the Americas. Initiatives to control Trypanosoma cruzi transmission via blood transfusion and non-native triatomine-bug vectors have yielded crucial advances; native vectors, however, actively bridge wild and domestic/peri-domestic transmission cycles throughout the region, and tens of thousands of people become infected each year. Oral-transmission outbreaks, urbanisation, and vertical transmission are additional/emerging issues calling for innovative strategic thinking. While critical for advocacy and sustained public health action, assessing Chagas disease burden remains difficult; the often-asymptomatic nature of T. cruzi infection, healthcare access limitations, pervasive underreporting, and other methodological hurdles inherent to reliably measuring incidence, prevalence, and disease progression all contribute to the difficulty. Whether and how parasite, vector, and host genetic makeups affect transmission dynamics and epidemiology is also unclear. Continued high-quality research and long-term, adaptive strategies combining vector control surveillance with enhanced case detection and integral patient care remain critical to effectively address the ethical and societal challenge of Chagas disease control. This is the first in a Series of five papers about Chagas Disease. All papers in the Series are available at https://www.thelancet.com/series/chagasdisease.

Keywords: Chagas disease; Control; Disease burden; Transmission; Trypanosoma cruzi.

Fig. 1

Ecoepidemiology and transmission dynamics of Chagas disease in the Americas.

Fig. 2

Distribution of Trypanosoma cruzi vector species in the Americas. Main domiciliated vector species (Panel A): larger and darker points correspond to records within the ecoregion-level native range of each species (light-coloured shapes), and smaller and lighter points to recordsof non-native populations (some of which have already been eliminated).^, Other important vector species (Panel B). Data sourced mainly from DataTri 2022.^,

Fig. 3

Distribution of DTUs in the Americas in vectors, non-human animals, and humans. Distribution of DTUs identified in vectors (Panel A), non-human animals (Panel B), and humans (Panel C). The size or shape of the symbols does not indicate the exact geographic location or frequency as some points may be overlapped. Map created with R Software. Data source.