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Mem Inst Oswaldo Cruz, Rio de Janeiro, VOLUME 121 | 2026

Research Articles

Detection of Trypanosoma cruzi-infected triatomines in Iquitos: possible incipient colonisation in the largest metropolis of the Peruvian Amazon

Fabiola Díaz-Soria^1,+, Karine Zevallos², Bryan Cabrera-Campos³, Carmen Sinti-Hesse¹, Sebastià Jaume-Ramis⁴, Wieslawa Alava-Flores¹, Darcy Acho-Bernuy¹, Silvia Vega-Chirinos³, Jesús Pinto-Caballero⁵, César Ramal-Asayag^2,6, Moisés Sihuincha⁷, Claudia Paredes-Esquivel^4,8

¹National Institute of Health, Centre for Tropical Diseases Research Hugo Pesce - Maxime Kuczynski, Iquitos, Peru
²Universidad Nacional de la Amazonia Peruana, Faculty of Human Medicine, Iquitos, Peru
³National Institute of Health, National Centre for Public Health, Laboratory of Chagas, Lima, Peru
⁴University of the Balearic Islands, Mediterranean Parasitology and Ecoepidemiology Research Group, Palma, Spain
⁵National Institute of Health, Laboratory of Entomology, Lima, Peru
⁶Hospital Regional de Loreto, Iquitos, Peru
⁷Arzobispo Loayza National Hospital, Lima, Peru
⁸Biomedical Research Networking Center for Infectious Diseases, Madrid, Spain

DOI: 10.1590/0074-02760240257

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ABSTRACT

BACKGROUND While Chagas disease (CD) has been controlled in many South American regions, the Amazon basin has emerged as a new focus of transmission. Metropolitan Iquitos (Loreto, Peru), has recently shown signs of potential disease emergence.
OBJECTIVE To assess the risk of CD transmission by evaluating triatomine presence and infection rates in households across Iquitos and nearby communities.
METHODS Entomological surveillance was conducted in domestic and peridomestic environments, following blood donor screenings (2011-2018) that confirmed local Trypanosoma cruzi cases. Triatomines were collected manually, with traps, and through community reporting. Specimens were identified, epidemiological indices calculated, and infestation risk factors analysed using penalised logistic regression, receiver operating characteristic (ROC)/area under the curve (AUC) metrics, and exploratory principal component analysis (PCA).
FINDINGS Of 142 houses visited, 113 were inspected, yielding a density index of 0.26. Nine houses were infested, mostly in Loboyacu, with 29 adult triatomines collected — by Rhodnius robustus (89.7%) and Panstrongylus geniculatus. T. cruzi infection was confirmed, and palm roofs emerged as the strongest predictor of infestation [odds ratio (OR) > 16, p < 0.001].
MAIN CONCLUSIONS This first evidence of T. cruzi circulation in sylvatic triatomines within Metropolitan Iquitos highlights an emerging risk of CD. Although vectors remain scarce, palm-roofed houses, deforestation, and urban expansion may facilitate future transmission.

key words: Chagas disease American trypanosomiosis Trypanosoma cruzi Peru Amazon emerging triatominae

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