Humans as blood-feeding sources in sylvatic triatomines of Chile unveiled by next-generation sequencing

San Juan, E., Araya-Donoso, R., Sierra-Rosales, C., Correa, J. P., Quiroga, N., Campos-Soto, R., Solari, A., Llewellyn, M. , Bacigalupo, A. and Botto-Mahan, C. (2023) Humans as blood-feeding sources in sylvatic triatomines of Chile unveiled by next-generation sequencing. Parasites and Vectors, 16, 225. (doi: 10.1186/s13071-023-05841-x) (PMID:37415248) (PMCID:PMC10327138)

Abstract

Background: Triatomines are blood-sucking insects capable of transmitting Trypanosoma cruzi, the parasite that causes Chagas disease in humans. Vectorial transmission entails an infected triatomine feeding on a vertebrate host, release of triatomine infective dejections, and host infection by the entry of parasites through mucous membranes, skin abrasions, or the biting site; therefore, transmission to humans is related to the triatomine–human contact. In this cross-sectional study, we evaluated whether humans were detected in the diet of three sylvatic triatomine species (Mepraia parapatrica, Mepraia spinolai, and Triatoma infestans) present in the semiarid–Mediterranean ecosystem of Chile. Methods: We used triatomines collected from 32 sites across 1100 km, with an overall T. cruzi infection frequency of 47.1% (N = 4287 total specimens) by conventional PCR or qPCR. First, we amplified the vertebrate cytochrome b gene (cytb) from all DNA samples obtained from triatomine intestinal contents. Then, we sequenced cytb-positive PCR products in pools of 10–20 triatomines each, grouped by site. The filtered sequences were grouped into amplicon sequence variants (ASVs) with a minimum abundance of 100 reads. ASVs were identified by selecting the best BLASTn match against the NCBI nucleotide database. Results: Overall, 16 mammal (including human), 14 bird, and seven reptile species were identified in the diet of sylvatic triatomines. Humans were part of the diet of all analyzed triatomine species, and it was detected in 19 sites representing 12.19% of the sequences. Conclusions: Sylvatic triatomine species from Chile feed on a variety of vertebrate species; many of them are detected here for the first time in their diet. Our results highlight that the sylvatic triatomine–human contact is noteworthy. Education must be enforced for local inhabitants, workers, and tourists arriving in endemic areas to avoid or minimize the risk of exposure to Chagas disease vectors.

• Item Type: Articles
• Additional Information: This study was funded by the Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) [grants no. 1221045, 1170367 (CBM and JPC), 1190392 (AS) and 1140521 (CBM)], VID-UChile ENL01/21, partially by Universidad Viña del Mar project FIIUVM-CTC-2211 (RCS), and ANID-Vinculación Internacional-FOVI1220125 (CBM, AB and ML). RAD and AB were supported by Agencia Nacional de Investigación y Desarrollo (ANID) Programa Becas—Doctorado Becas Chile 2019 [grants no. 72200094 and 72200391, respectively].
• Keywords: Chile, Triatoma infestans, NGS, Chagas disease, Mepraia spinolai, Mepraia parapatrica.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bacigalupo Bacigalupo, Antonella Eugenia and Llewellyn, Professor Martin
• Authors: San Juan, E., Araya-Donoso, R., Sierra-Rosales, C., Correa, J. P., Quiroga, N., Campos-Soto, R., Solari, A., Llewellyn, M., Bacigalupo, A., and Botto-Mahan, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Parasites and Vectors
• Publisher: BioMed Central
• ISSN: 1756-3305
• ISSN (Online): 1756-3305
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Parasites and Vectors 16: 225
• Publisher Policy: Reproduced under a Creative Commons License