Trypanosoma cruzi
Nilmar Silvio Moretti,1,
* Renato Arruda Mortara,1
and Sergio Schenkman1
1
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Trypanosoma cruzi is the etiological agent of American trypanosomiasis, or Chagas disease, and is transmitted
mainly by blood-sucking reduviid insects in endemic countries. Metacyclic trypomastigotes released in the feces
during the insect blood meal enter a mammalian host through skin wounds or mucosal membranes and invade surrounding
cells. After cell invasion, metacyclic trypomastigotes are restrained within a parasitophorous vacuole (PV),
from where they escape, transform into amastigotes, and multiply in the cytosol. Later, following binary division,
amastigotes differentiate back into highly motile trypomastigotes that are released upon cell lysis. They can infect
neighboring cells, migrate to different tissues, or be ingested by an insect vector. The parasites in the tissues, associated
with an immune response, contribute to the chronic symptoms of the disease. Reactive oxygen species
(ROS), among other factors, play an important role during parasite multiplication and interstage transformation.
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KEY FACTS:
The Brazilian physician Carlos Chagas first
discovered the parasite and defined its life
cycle, vector, and disease symptoms.
T. cruzi presents replicating and
nonreplicating forms. Transition between
these forms relies on environmental signals,
including ROS.
T. cruzi is classified into seven discrete
typing units (DTUs), TcI–TcVI and Tcbat,
based on genetic and biological diversity,
which show different clinical manifestations
and drug sensitivity.
The parasite can invade and replicate within
many cell types, including macrophages
and smooth and striated muscle cells.
DISEASE FACTS:
The disease is endemic in southern USA
and 21 countries across Latin America,
with ∼7 million people infected and 70
million at risk.
Migratory movements are increasing the
disease risk in the USA, Europe, and Asia.
T. cruzi is also transmitted congenitally,
by blood transfusion, by organ transplantation,
and by ingestion of contaminated
food and drink.
The acute phase happens at any age
and is usually asymptomatic. Parasites
are found in the peripheral circulation.
The chronic phase manifests ∼20 years
from the first infection, with low parasite
burden, causing cardiomyopathy,
megaesophagus, and megacolon.
Benznidazole and nifurtimox are available
drugs and are effective in the acute
phase but less dependable for chronicphase
cure.
TAXONOMY AND CLASSIFICATION:
KINGDOM: Protozoa
PHYLUM: Euglenozoa
CLASS: Kinetoplastea
ORDER: Kinetoplastida
FAMILY: Trypanosomatidae
GENUS: Trypanosoma
SPECIES: T. cruzi
*Correspondence:
nilmar.moretti@unifesp.br (N.S. Moretti).
404 Trends in Parasitology, April 2020, 36, No. 4 © 2019 Elsevier Ltd. All rights reserved. https://doi.org/10.1016/j.pt.2019.10.002
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Acknowledgments
This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), grant 2018/09948-0 to N.S.M.; 16/15000-4 to R.A.M. and 15/22031-0 to S.S.;
and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant 424729/2018-0 to N.S.M.; 302068/2016-3 to R.A.M. and by Instituto Nacional de Ciência e
Tecnologia de Vacinas (INCTV) to S.S.
Resources
www.dndi.org/diseases-projects/chagas/
www.cdc.gov/parasites/chagas/
www.who.int/chagas/en/
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