High Diversity of Trypanosoma Cruzi Discrete Typing Units Circulating in Triatoma in Western Mexico

Chagas disease is caused by the protozoan parasite <em>Trypanosoma cruzi</em>, which is transmitted to domestic and sylvatic mammals via the feces of hematophagous hemiptera of the subfamily Triatominae (Reduviidae). <em>Trypanosoma cruzi</em> is found only in the Americas and displays remarkable genetic diversity. Seven discrete typing units (DTUs) are currently recognized (TcI–TcVI and TcBat). In Jalisco, Mexico, where Chagas disease has a high prevalence rate, TcI has historically been the only DTU reported. This study focused on the molecular identification of <em>T. cruzi</em> DTUs circulating in <em>Triatoma</em> near the Estación<em> </em>de Biología Chamela, on the southwest coast of Jalisco, Mexico. I collected DNA from 95 <em>Triatoma </em>bugs. <em>Trypanosoma cruzi </em>infection was detected using PCR primers specific for the minicircle variable region of the parasite’s kinetoplast DNA (kDNA). <em>T</em><em>rypanosoma cruzi</em> DTUs were identified by amplifying the intergenic region of the mini-exon, and the genes <em>24S</em><em>α, 18S</em>, <em>TcSC5D</em>, and <em>TcMK</em>. Two species of<em> Triatoma </em>were collected, <em>Triatoma longipennis</em> and <em>T. bolivari,</em> with an overall infection rate of 59%. There was high genetic diversity of <em>T. cruzi</em> in my samples, with the DTUs TcI, TcII, TcIV, TcVI, and Tcbat being identified. This is the first report of TcVI and Tcbat in North America. In the <em>Triatoma</em> found to be infected, 96% had TcI, 35% TcII, 2% TcIV, 25% TcVI, and 2% Tcbat. Several vertebrate hosts for <em>Triatoma</em> were also identified from visible blood within Triatominaes’ gut using PCR primers for <em>cytochrome b</em> and <em>cytochrome oxidase subunit I</em> genes. My observations indicate a much higher diversity of <em>T. cruzi</em> DTUs in <em>Triatoma </em>than previously reported in Jalisco. The results have important implications for understanding the geographical distribution of <em>T. cruzi </em>DTUs and epidemiology of Chagas disease in Mexico.

Name thesis:degree_name

Master of Science (MS)

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2016

Author dc:creator

• Nguyen, Uyen T.

Contributors dc:contributor

• Gabrielle Stryker
• Blaise Dondji
• Daniel D. Beck

• Trypanosoma cruzi
• Genotyping
• Discrete typing units (DTUs)
• Triatoma longipennis
• Triatoma bolivari
• Seasonally dry tropical forest
• Jalisco
• Mexico
• Molecular Genetics
• Other Immunology and Infectious Disease
• Parasitology

Language dc:language

English

Repository record dc:identifier

https://digitalcommons.cwu.edu/etd/510

OAI identifier oai:identifier

oai:digitalcommons.cwu.edu:etd-1512