Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment

Infection with the protozoan parasite Trypanosoma cruzi is generally well-controlled by host immune responses, but appears to be rarely eliminated. The resulting persistent, low-level infection results in cumulative tissue damage with the greatest impact generally in the heart in the form of chagasi...

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Main Authors: Brooke E White, Carolyn L Hodo, Sarah Hamer, Ashley B Saunders, Susana A Laucella, Daniel B Hall, Rick L Tarleton
Format: Article
Language:English
Published: eLife Sciences Publications Ltd 2025-04-01
Series:eLife
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Online Access:https://elifesciences.org/articles/104547
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author Brooke E White
Carolyn L Hodo
Sarah Hamer
Ashley B Saunders
Susana A Laucella
Daniel B Hall
Rick L Tarleton
author_facet Brooke E White
Carolyn L Hodo
Sarah Hamer
Ashley B Saunders
Susana A Laucella
Daniel B Hall
Rick L Tarleton
author_sort Brooke E White
collection DOAJ
description Infection with the protozoan parasite Trypanosoma cruzi is generally well-controlled by host immune responses, but appears to be rarely eliminated. The resulting persistent, low-level infection results in cumulative tissue damage with the greatest impact generally in the heart in the form of chagasic cardiomyopathy. The relative success in immune control of T. cruzi infection usually averts acute phase death but has the negative consequence that the low-level presence of T. cruzi in hosts is challenging to detect unequivocally. Thus, it is difficult to identify those who are actively infected and, as well, problematic to gauge the impact of treatment, particularly in the evaluation of the relative efficacy of new drugs. In this study, we employ DNA fragmentation and high numbers of replicate PCR reaction (‘deep-sampling’) and to extend the quantitative range of detecting T. cruzi in blood by at least three orders of magnitude relative to current protocols. When combined with sampling blood at multiple time points, deep sampling of fragmented DNA allowed for detection of T. cruzi in all infected hosts in multiple host species, including humans, macaques, and dogs. In addition, we provide evidence for a number of characteristics not previously rigorously quantified in the population of hosts with naturally acquired T. cruzi infection, including, a >6 log variation between chronically infected individuals in the stable parasite levels, a continuing decline in parasite load during the second and third years of infection in some hosts, and the potential for parasite load to change dramatically when health conditions change. Although requiring strict adherence to contamination–prevention protocols and significant resources, deep-sampling PCR provides an important new tool for assessing therapies and for addressing long-standing questions in T. cruzi infection and Chagas disease.
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spelling doaj-art-a4af3a41038b4b5ab0551bbc57dca11a2025-08-20T03:10:46ZengeLife Sciences Publications LtdeLife2050-084X2025-04-011410.7554/eLife.104547Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatmentBrooke E White0Carolyn L Hodo1Sarah Hamer2Ashley B Saunders3Susana A Laucella4Daniel B Hall5Rick L Tarleton6https://orcid.org/0000-0002-9589-5243Center for Tropical and Emerging Global Disease, Athens, United StatesMichale E. Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Bastrop, United StatesDepartment of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, United StatesDepartment of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, United StatesResearch Department, Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben", Buenos Aires, Argentina. Chagas Disease Unit, Hospital Interzonal General de Agudos Eva Perón, Buenos Aires, ArgentinaDepartment of Statistics, University of Georgia, Athens, United StatesCenter for Tropical and Emerging Global Disease, Athens, United States; Department of Cellular Biology, University of Georgia, Athens, United StatesInfection with the protozoan parasite Trypanosoma cruzi is generally well-controlled by host immune responses, but appears to be rarely eliminated. The resulting persistent, low-level infection results in cumulative tissue damage with the greatest impact generally in the heart in the form of chagasic cardiomyopathy. The relative success in immune control of T. cruzi infection usually averts acute phase death but has the negative consequence that the low-level presence of T. cruzi in hosts is challenging to detect unequivocally. Thus, it is difficult to identify those who are actively infected and, as well, problematic to gauge the impact of treatment, particularly in the evaluation of the relative efficacy of new drugs. In this study, we employ DNA fragmentation and high numbers of replicate PCR reaction (‘deep-sampling’) and to extend the quantitative range of detecting T. cruzi in blood by at least three orders of magnitude relative to current protocols. When combined with sampling blood at multiple time points, deep sampling of fragmented DNA allowed for detection of T. cruzi in all infected hosts in multiple host species, including humans, macaques, and dogs. In addition, we provide evidence for a number of characteristics not previously rigorously quantified in the population of hosts with naturally acquired T. cruzi infection, including, a >6 log variation between chronically infected individuals in the stable parasite levels, a continuing decline in parasite load during the second and third years of infection in some hosts, and the potential for parasite load to change dramatically when health conditions change. Although requiring strict adherence to contamination–prevention protocols and significant resources, deep-sampling PCR provides an important new tool for assessing therapies and for addressing long-standing questions in T. cruzi infection and Chagas disease.https://elifesciences.org/articles/104547Trypanosoma cruziChagas diseasetest of curePCR
spellingShingle Brooke E White
Carolyn L Hodo
Sarah Hamer
Ashley B Saunders
Susana A Laucella
Daniel B Hall
Rick L Tarleton
Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
eLife
Trypanosoma cruzi
Chagas disease
test of cure
PCR
title Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
title_full Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
title_fullStr Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
title_full_unstemmed Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
title_short Serial ‘deep-sampling’ PCR of fragmented DNA reveals the wide range of Trypanosoma cruzi burden among chronically infected human, macaque, and canine hosts, and allows accurate monitoring of parasite load following treatment
title_sort serial deep sampling pcr of fragmented dna reveals the wide range of trypanosoma cruzi burden among chronically infected human macaque and canine hosts and allows accurate monitoring of parasite load following treatment
topic Trypanosoma cruzi
Chagas disease
test of cure
PCR
url https://elifesciences.org/articles/104547
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