Banca de QUALIFICAÇÃO: MARICÉLIA DE AQUINO SANTANA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARICÉLIA DE AQUINO SANTANA
DATE: 25/03/2026
TIME: 14:00
LOCAL: REMOTA
TITLE:

THE TRANSMISSION POTENTIAL AND GENETIC DIVERSITY OF TRYPANOSOMA CRUZI IN THE STATE OF PIAUÍ: EPIDEMIOLOGICAL AND TAXONOMIC PROFILE OF TRIATOMINES

KEY WORDS:

Trypanosoma cruzi. Chagas disease. Natural infection. Vector transmission. Genotyping.

PAGES: 33
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:

Introduction: The transmission of Chagas disease is associated with the presence of infected triatomines and the circulation of different Trypanosoma cruzi genotypes in both anthropogenic and sylvatic environments. The adaptation of vector species to intradomiciliary and peridomiciliary settings increases the risk of human infection and complicates control efforts. Identifying predominant species, colonized environments, and circulating Discrete Typing Units (DTUs) provides strategic information for entomological surveillance and for guiding control measures tailored to regional realities. Objective: This study evaluated the presence of triatomines and the distribution of T. cruzi DTUs isolated from these vectors in different municipalities in southeastern Piauí State. Methods: Active searches for triatomines were conducted in rural areas of eight municipalities, 24 rural communities, and 281 housing units between July 2022 and November 2023. Triatomine fauna, natural infection by T. cruzi, and their association with blood meal sources were evaluated. Genotyping was performed using markers from the mitochondrial cytochrome oxidase subunit II gene (COII), the divergent D71 domain of the 24Sα ribosomal DNA (rDNA) gene, and the intergenic spacer of the miniexon genes (SL-IR). In addition, was morphologically analyzed using dichotomous keys, the possible occurrence of natural hybrids within Triatoma brasiliensis complex. Results: A total of 661 triatomines were captured in the investigated municipalities, with predominance of Triatoma brasiliensis (92.1%), followed by Triatoma pseudomaculata (7.3%), Panstrongylus lutzi (1%), and Rhodnius sp. (0.4%). T. brasiliensis was found in intradomiciliary, peridomiciliary, and sylvatic environments, whereas T. pseudomaculata occurred exclusively in peridomiciliary areas. Natural infection by trypanosomatids was detected in 12% (67/556) of the examined specimens, with T. brasiliensis showing an infection rate of 11.1% (62/556). Blood meal analysis indicated eclectic feeding behavior, with detection of cat DNA in 17.4% (4/23), human in 13% (3/23), dog in 8.7% (2/23), and chicken in 8.7% (2/23) of samples. Of the 67 infected triatomines, the parasite was successfully isolated from 47.7% (32/67) samples, all of which were genotyped. Molecular analysis revealed circulation of DTUs TcI (9.4%), TcII (75%), and TcIII (9.4%), with distinct environmental distribution patterns. Notably, TcIII was detected in both peridomiciliary and intradomiciliary environments, as well as singles infections (TcI, TcII, and TcIII) and mixed infections (TcII+TcIII), primarily in T. brasiliensis, reinforcing its role as a key vector at the interface between the sylvatic and domestic transmission cycles of the parasite. Conclusion: The results demonstrate that T. brasiliensis remains highly relevant from an epidemiological perspective in the semi-arid region of Piauí. This is due to its remarkable ability to adapt to various ecotopes, its wide geographical distribution, its high rate of natural infection by T. cruzi and the diversity of DTUs. This scenario highlights the importance of integrated entomological surveillance to minimise contact between vectors and humans and between vectors and domestic animals.

COMMITTEE MEMBERS:
Presidente - ***.985.294-** - LUCIA MARIA DA CUNHA GALVAO - UFRN
Externo ao Programa - 1752367 - PAULO MARCOS DA MATTA GUEDES - nullExterna ao Programa - 1715271 - RENATA ANTONACI GAMA - null