By: Charles Ebikeme
On March 5th 2001, a 37 year old woman went into surgery to have a kidney and pancreas transplant from a donor that had already passed away. Once discharged, she returned to the hospital six weeks later to be treated for a sudden onset of fever, of unknown origin. She would die six months later, on the first week of October.
What turned out to be the first recognized case of a Chagas disease infection through solid-organ transplantation in the Unites States came after the physician identified the parasites in a peripheral blood smear. Upon identification the physician immediately notified the Center for Disease Control (CDC). Upon further investigation it was discovered that other patients had received infected organs from the same donor- 32 year old woman who had received the liver and a 69 year old woman who received the other kidney. Both organs were found to be infectious. The donor of the infected organs was an immigrant from Central America.
At the time, no protocol or policy was in place for the regular screening of organ donations for T. cruzi, the parasite that causes Chagas disease — something that was routinely done in Chagas endemic areas. And no test was licensed for screening organ or blood donors. Today, two Chagas tests are available, out of a full complement of 60 that are licensed and routinely used to screen organs and blood donation for a wide range of infectious agents (including HIV, hepatitis and West Nile virus).
After the infection was detected, all three women were treated with nifurtimox — a drug not available in the US at the time and a drug that, over ten years later, still only has a single manufacturer. Today, nifurtimox, which dates back to 1960, is available for US$48 per treatment regimen — the equivalent of a month of a Bolivian miner’s salary.
Of the three women that were infected, it was only the 69 year old woman that would survive the parasitic infection. The woman who received the kidney and pancreas transplants was the most immunosuppressed of the three patients, and her death was a result of immunosuppression. She died even after completing a full course (4 months) of treatment with nifurtimox.
The original organ donor, the immigrant from Central America, most likely acquired Chagas from an infected kissing bug. As it bites, the insect carrying the parasite deposits feces on the victim’s skin, and when the person rubs the bite wound, the feces containing the parasite enters the bloodstream.
Blood and organ donor screening programs across the Americas and North America have essentially eliminated transmission via this route. However, some cases till turn up. The lack of awareness of the disease among US healthcare providers complicates the issue.
Chagas, once thought of and regarded as an exotic disease, given little attention, is increasingly being diagnosed in non-endemic areas. In 2009 it was estimated that 300,000 people living in the US were chronically infected with the parasite. In Europe, Chagas has been reported from congenital transmission (from mother to infant), in a recipient of a bone marrow transplant, and among Brazilian immigrants of Japanese origin in Japan.
Patterns of emigration have drastically changed the epidemiology of this disease over the recent decades. Immigration is one reason, but not the only one.
A new study has shown that a high proportion of triatomine bugs collected in Arizona and California had fed on humans, while others were positive for T. cruzi parasite infection. This new study essentially indicates that the potential exists for vector transmission of Chagas disease in the US. Up until now, the most common result of a triatomine bite was an allergic reaction.
Editor’s note: Sabin president Dr. Peter Hotez recently summarized the incidence of neglected tropical disease infection in Texas and Mexico, including a review of Chagas disease transmission in the region, in a paper published in PLoS Neglected Tropical Diseases.
Charles Ebikeme is a writer and scientist with a research background in tropical diseases. Possessing a MSc from the London School of Hygiene & Tropical Medicine, and a PhD in Parasitology from the University of Glasgow, Charles currently blogs and writes for the All Results Journals – a new publication system focusing on negative results – covering topics on the hidden side of the scientific publication process.