Trypanosoma cruzi is a protozoan parasite that can cause an insidious onset of Chagas disease, a fatal cardiac disease in humans and dogs. The parasite is transmitted via triatomine insects, commonly called kissing bugs. In Latin America T. cruzi is recognized as an economically important parasite; however, there is limited research regarding its spread and virulence in the USA. As a result, while the genetic diversity of the T. cruzi parasite has been well studied in Latin America less is known about the strains endemic to the USA.
Researchers from the University of California, Davis, and the London School of Hygiene and Tropical Medicine assessed the prevalence of T. cruzi from northern and southern California regions. The researchers used a combination of methods to obtain triatomine insects, including active collection via black light traps and the enlistment of private property owners and public health officials in specimen submission. DNA was extracted from the specimens and screened for T. cruzi via molecular techniques. Positive samples were genetically typed into one of six recognized T. cruzi subgroups (TcI - TcVI). Finally, the researchers performed genetic analyses to examine the potential virulence of the California T. cruzi samples as compared to infective T. cruzi strains from Latin America.
Of the 29 specimens from northern California 55% were infected, while T. cruzi was detected in 34% of the 53 samples collected from one of the southern California locations. Two separate subtypes were found -- with 20 parasites falling into the TcI subgroup and 2 into TcIV. The TcIV subgroup was not detected in the northern California region. Genetic analyses did not reveal any particular unique characteristics to distinguish the California samples from several Latin American strains known to infect humans.
This research suggests that the apparent rarity of locally-acquired Chagas disease in the USA is unlikely due to any genetic difference in the infectious capabilities of the parasite. Rather, the fact that local triatomine species (e.g. Triatoma protracta) do not frequently colonize human homes, likely translates to decreased T. cruzi transmission. Alternatively, locally-acquired Chagas disease may simply be underdiagnozed. At present only four states in the USA list Chagas disease as a reportable illness, and California is not among them. This means that the public, as well as physicians and veterinary practitioners, may have decreased awareness of the dangers posed by this disease. Based on this research, in areas where Triatoma protracta populations are evident, Chagas disease should be considered as a potential cause of cardiac illness in humans and dogs.
Please contact email@example.com if you would like more information about our content and specific topics of interest.
All works published in PLOS Neglected Tropical Diseases are open access, which means that everything is immediately and freely available. Use this URL in your coverage to provide readers access to the paper upon publication:
Lisa A. Shender
About PLOS Neglected Tropical Diseases
PLOS Neglected Tropical Diseases is a peer-reviewed, open-access journal devoted to the pathology, epidemiology, prevention, treatment, and control of the neglected tropical diseases, as well as public policy relevant to this group of diseases. All works published in PLOS Neglected Tropical Diseases are open access, which means that everything is immediately and freely available subject only to the condition that the original authorship and source are properly attributed. The Public Library of Science uses the Creative Commons Attribution License, and copyright is retained by the authors.
About the Public Library of Science
The Public Library of Science (PLOS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.
PLOS Journals publish under a Creative Commons Attribution License , which permits free reuse of all materials published with the article, so long as the work is cited (e.g., Kaltenbach LS et al. (2007) Huntington Interacting Proteins Are Genetic Modifiers of Neurodegeneration. PLOS Genet 3(5): e82. doi:10.1371/journal.pgen.0030082). No prior permission is required from the authors or publisher. For queries about the license, please contact the relative journal contact indicated here: http://www.