Background Trypanosoma cruzi, the causative agent of Chagas disease, is subdivided into distinct genetic groups known as Discrete Typing Units (DTUs), each with distinct genetic traits that influence epidemiology and transmission dynamics. Several triatomine species serve as potential vectors of T. cruzi in the United States. However, despite the growing number of Chagas disease cases in the country, little is known about the genetic diversity and population structure of T. cruzi in natural vector populations. Methodology/Principal Findings We applied a multilocus metabarcoding approach to improve DTU resolution and characterize the genetic diversity and structure of T. cruzi in triatomines collected across five states of the southern United States. Five single-copy nuclear markers and one mitochondrial marker were amplified and processed by high-throughput sequencing to assess genetic diversity. We recovered 35 nuclear and 15 mitochondrial haplotypes from 70 infected specimens. Overall, genetic diversity was low ({pi} < 0.01 at all nuclear loci), with DTUs TcI and the North American lineage of TcIV detected, TcI being the most prevalent. Geographic structuring was particularly evident in TcI strains, which exhibited a distinctive haplotype profile in Florida populations, potentially linked to the recently revalidated vector species Triatoma ambigua. Mitochondrial introgression from TcIV into TcI suggests inter-DTU genetic exchange in these populations. Multiple haplotypes within individual insects detected across single-copy nuclear markers, support multiclonal infection as common feature of T. cruzi in natural vectors. Conclusions/Significance These findings provide new insights into the genetic landscape and evolution of T. cruzi in the United States. Evolutionary connectivity through mitochondrial introgression and frequent multiclonality highlights the importance of deep sequencing approaches for resolving T. cruzi genetic diversity, with direct implications for understanding for transmission dynamics, disease monitoring and control.

Background Trypanosoma cruzi, the causative agent of Chagas disease, is subdivided into distinct genetic groups known as Discrete Typing Units (DTUs), each with distinct genetic traits that influence epidemiology and transmission dynamics. Several triatomine species serve as potential vectors of T. cruzi in the United States. However, despite the growing number of Chagas disease cases in the country, little is known about the genetic diversity and population structure of T. cruzi in natural vector populations. Methodology/Principal Findings We applied a multilocus metabarcoding approach to improve DTU resolution and characterize the genetic diversity and structure of T. cruzi in triatomines collected across five states of the southern United States. Five single-copy nuclear markers and one mitochondrial marker were amplified and processed by high-throughput sequencing to assess genetic diversity. We recovered 35 nuclear and 15 mitochondrial haplotypes from 70 infected specimens. Overall, genetic diversity was low ({pi} < 0.01 at all nuclear loci), with DTUs TcI and the North American lineage of TcIV detected, TcI being the most prevalent. Geographic structuring was particularly evident in TcI strains, which exhibited a distinctive haplotype profile in Florida populations, potentially linked to the recently revalidated vector species Triatoma ambigua. Mitochondrial introgression from TcIV into TcI suggests inter-DTU genetic exchange in these populations. Multiple haplotypes within individual insects detected across single-copy nuclear markers, support multiclonal infection as common feature of T. cruzi in natural vectors. Conclusions/Significance These findings provide new insights into the genetic landscape and evolution of T. cruzi in the United States. Evolutionary connectivity through mitochondrial introgression and frequent multiclonality highlights the importance of deep sequencing approaches for resolving T. cruzi genetic diversity, with direct implications for understanding for transmission dynamics, disease monitoring and control.

Insects of the subfamily Triatominae, commonly known as kissing bugs, are obligate blood-feeding vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Rhodnius prolixus is among the most epidemiologically important vectors in Latin America, whereas Triatoma rubida frequently invades homes and is a potential vector in the southern United States and northern Mexico. Triatomines likely evolved from predatory reduviid assassin bugs through a transition from feeding on arthropods associated with vertebrate hosts to feeding directly on vertebrate blood. To investigate the genomic basis of this ecological and dietary shift, we generated highly contiguous, near chromosome-level genome assemblies and structural gene annotations for R. prolixus and T. rubida. The new R. prolixus assembly improves scaffold N50 more than 40-fold over the current reference genome, from 1.1 to 43.9 Mb, while reducing assembly gaps by several orders of magnitude. Both assemblies exceed 97% BUSCO completeness. Comparative analyses with representative hemipteran genomes revealed expansions of gene families associated with chemosensation and metabolism, including detoxification, protein degradation, and digestion, together with signatures of positive selection in genes involved in digestive and sensory functions. These assemblies represent the most contiguous and complete genomic resources available for Triatominae and provide a robust foundation for investigating vector biology, host adaptation, and the evolutionary origins of blood feeding within Reduviidae.

Insects of the subfamily Triatominae, commonly known as kissing bugs, are obligate blood-feeding vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Rhodnius prolixus is among the most epidemiologically important vectors in Latin America, whereas Triatoma rubida frequently invades homes and is a potential vector in the southern United States and northern Mexico. Triatomines likely evolved from predatory reduviid assassin bugs through a transition from feeding on arthropods associated with vertebrate hosts to feeding directly on vertebrate blood. To investigate the genomic basis of this ecological and dietary shift, we generated highly contiguous, near chromosome-level genome assemblies and structural gene annotations for R. prolixus and T. rubida. The new R. prolixus assembly improves scaffold N50 more than 40-fold over the current reference genome, from 1.1 to 43.9 Mb, while reducing assembly gaps by several orders of magnitude. Both assemblies exceed 97% BUSCO completeness. Comparative analyses with representative hemipteran genomes revealed expansions of gene families associated with chemosensation and metabolism, including detoxification, protein degradation, and digestion, together with signatures of positive selection in genes involved in digestive and sensory functions. These assemblies represent the most contiguous and complete genomic resources available for Triatominae and provide a robust foundation for investigating vector biology, host adaptation, and the evolutionary origins of blood feeding within Reduviidae.

Satellite DNAs comprise the major component of the Triatoma rubrofasciata repeatome, highlighting their central role in genome composition and architecture. Satellite DNA families show recent amplif.....

This chapter aims to introduce the reader to the importance of bugs from the Triatominae subfamily, which transmit the parasite that causes Chagas disease. It discusses the role of genomics in advanci...

Publication date: Available online 19 November 2025 Source: Acta Tropica Author(s): Jorge Jesús Rodríguez-Rojas, Edith Araceli Fernández-Figueroa, Pilar de Jesús Salas-Rodríguez, Josué Severo Ortiz-Barrera, Herón Huerta, Mario Octavio González-Reyes, Rosa María Sánchez-Casas, Ildefonso Fernández-Salas, Gabriel Gutiérrez-Granados, Ángel Rodríguez-Moreno

Publication date: Available online 19 November 2025 Source: Acta Tropica Author(s): Jorge Jesús Rodríguez-Rojas, Edith Araceli Fernández-Figueroa, Pilar de Jesús Salas-Rodríguez, Josué Severo Ortiz-Barrera, Herón Huerta, Mario Octavio González-Reyes, Rosa María Sánchez-Casas, Ildefonso Fernández-Salas, Gabriel Gutiérrez-Granados, Ángel Rodríguez-Moreno

AbstractChagas disease is one of the most important vector-borne diseases in Mexico. Triatoma longipennis (Usinger. 1939) is one of the most epidemiologically important vector species of Trypanosoma cruzi (Chagas, 1909), the etiological agent of Chagas disease. This study reports the third collection of T. longipennis from the state of Hidalgo, Mexico. This paper evaluates and compares feeding and defecation behaviors for each instar of two populations of T. longipennis recently detected in Hidalgo, Mexico. No significant differences were noted between the two populations in the mean time to initiate feeding (immediate “attack”), feeding times (> 10 min), and defecation delay (when feeding or immediately after feeding: 77% to 99% vs 84.5% to 100%). These observed behaviors in the two populations of T. longipennis from Hidalgo align with the characteristics of an effective transmitter of T. cruzi. Given these results, the recently detected populations of T. longipennis could be considered significant potential vectors of T. cruzi to human populations and may replace key triatomine species within their new distribution area.

AbstractChagas disease is one of the most important vector-borne diseases in Mexico. Triatoma longipennis (Usinger. 1939) is one of the most epidemiologically important vector species of Trypanosoma cruzi (Chagas, 1909), the etiological agent of Chagas disease. This study reports the third collection of T. longipennis from the state of Hidalgo, Mexico. This paper evaluates and compares feeding and defecation behaviors for each instar of two populations of T. longipennis recently detected in Hidalgo, Mexico. No significant differences were noted between the two populations in the mean time to initiate feeding (immediate “attack”), feeding times (> 10 min), and defecation delay (when feeding or immediately after feeding: 77% to 99% vs 84.5% to 100%). These observed behaviors in the two populations of T. longipennis from Hidalgo align with the characteristics of an effective transmitter of T. cruzi. Given these results, the recently detected populations of T. longipennis could be considered significant potential vectors of T. cruzi to human populations and may replace key triatomine species within their new distribution area.

Residual spraying with pyrethroid insecticides is still the main strategy used to prevent vector-borne transmission of #Trypanosoma cruzi, the etiological agent of Chagas disease. The emergence of resistance to th...

Residual spraying with pyrethroid insecticides is still the main strategy used to prevent vector-borne transmission of #Trypanosoma cruzi, the etiological agent of Chagas disease. The emergence of resistance to th...

Residual spraying with pyrethroid insecticides is still the main strategy used to prevent vector-borne transmission of #Trypanosoma cruzi, the etiological agent of Chagas disease. The emergence of resistance to th...