Karius Medical Case Reports: Trypanosoma cruzi | Karius
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Karius Medical Case Reports: Trypanosoma cruzi

 

Chagas Disease is an illness that affects 8 million people worldwide and is caused by the unicellular protozoan parasite Trypanosoma cruzi. It was named for the Brazilian doctor Carlos Justiniano Chagas who discovered the disease in 1909.

Trypanosoma parasites are primarily transmitted between mammals by large triatomine insects that feed on blood and live predominantly in South America, Central America, and Mexico. Increasing global travel means that this disease can spread to other continents as well.

When a person is infected with this parasite, there may be inflammation near the site of infection, an acute phase lasting 2-3 months that can include (in rare circumstances) serious cardiac or central nervous system complications, and a chronic, potentially lifelong phase during which the infection may go unnoticed.  

Possible complications of T. cruzi infection during this chronic phase include heart disease (dilated cardiomyopathy), gastrointestinal disease (toxic megacolon), meningoencephalitis, reactivation of the infection, anemia, and other health issues. 

Current methods to diagnose Chagas Disease include repeated serology tests using ELISA and immunofluorescence assays, PCR on an infected tissue specimen, or xenodiagnosis, which involves feeding laboratory-raised triatomine insects with a sample from the patient and then interrogating the insects for parasites.

The Karius® Test is able to detect T. cruzi and over 1,000 other pathogens from a single blood draw by using next-generation sequencing and bioinformatics pipelines to identify the cell-free pathogen DNA.

Case Report: Treatment Change for Elderly Patient

Clinical Scenario: An elderly gentleman originally from Ecuador but having lived in the United States for the past several decades began experiencing neurologic symptoms suggesting a transient ischemic attack. He had a history of rheumatoid arthritis and had been taking methotrexate intermittently. The patient was treated for a presumed blood clot and his condition improved. 

The symptoms returned 2 weeks later, progressing to impaired speech and loss of consciousness. On admission to hospital, he was found to have diffuse cerebral edema. CSF and brain biopsy tissue samples were sent to the CDC for analysis, and a blood specimen was drawn for a Karius Test.

Karius Test Result: Trypanosoma cruzi

The brain biopsy tissue was suggestive of a parasitic infection, and the CSF PCR at the CDC was also positive for T. cruzi

Based on this confirmatory set of results from both Karius and the CDC, the patient was started on benznidazole for 60 days to treat Chagas Disease, with weekly blood draws for further testing to monitor his progression. 

 

This is part of a series of Karius Medical Case Reports. In this case, the Karius Test was able to accurately identify infection with T. cruzi in a clinically relevant timeframe, as correlated with CDC findings, thereby giving the physician additional confidence to provide precise treatment to the patient. We will discuss additional case reports in future posts.

 

References

 

  • World Health Organization: Chagas disease (American trypanosomiasis) - https://www.who.int/chagas/disease/en/
  • Meymandi et. al. Treatment of Chagas Disease in the United States. Curr Treat Options Infect Dis. 2018;10(3):373-388.
  • Jansen et. al. Trypanosoma cruzi transmission in the wild and its most important reservoir hosts in Brazil. Parasit Vectors. 2018 Sep 6;11(1):502.
  • Muller Kratz et. al. Clinical and pharmacological profile of benznidazole for treatment of Chagas disease. Expert Rev Clin Pharmacol. 2018 Oct;11(10):943-957.

 

DISCLAIMER: Case descriptions have been modified to protect patient privacy and, while every attempt has been made to provide accurate information, errors may occur. This information is provided for educational purposes only, and is not intended to be used as medical advice.