Diversitat genètica de Trypanosoma cruzi als Estats Units d'Amèrica

Abstract

Trypanosoma cruzi, a flagellated parasitic protozoan, is the causative agent of Chagas disease. The

infection has a zoonotic vectorial origin and was initially linked to rural areas of Latin America, where

it is endemic. However, human migratory flows have resulted in infected individuals being present

worldwide today. Currently, the World Health Organization (WHO) estimates that there are between

six and seven million people infected with T. cruzi. The United States of America (USA) is a special

case as, even though it is not considered a non-endemic country for Chagas disease, in the southern

states there is T. cruzi presence in various mammalian species circulating in an enzootic cycle.

Nevertheless, historically it has not become established in humans beyond sporadic cases. The genetic

diversity of this parasite is classified into Discrete Typing Units (DTUs). There are six different DTUs,

designated as TcI to TcVI. More recently, a seventh DTU has been postulated, provisionally named

Tcbat, due to its isolation in bats. The DTUs have different geographic distributions. While previous

knowledge indicates that the DTUs present in the USA are TcI and TcIV, the objective of this study is

to conduct a comprehensive analysis of the DTUs found in the country to gain more detailed information

about the genetic diversity of T. cruzi in the USA. For this purpose, a bibliographic search was made through the Web of Science portal using the keywords

"Trypanosoma cruzi" combined with "United States," "gen* diversity," "USA," and "discrete typing

unit." All results up to the search date were included, and all entries classified as articles or review

articles within the Document Types section were considered. Subsequently, the titles and abstracts of

the obtained articles were read, and in case of doubt, their content was also examined to select or discard

them, obtaining a final list of 24 articles. By reading the selected bibliography, data from the studies were compiled, resulting in a total of 1160

individual DTUs found in triatomines and 289 found in hosts. The combined results reveal that TcI and

TcIV are indeed the DTUs with the highest presence in the country, with TcI showing the highest

proportion. However, there is also a presence of TcII, TcV, and TcVI in much smaller percentages