by Leo O’Connor, Senior Editor, 360Dx, GenomeWeb
June 2, 2017
NEW YORK (360Dx) – A point-of-care diagnostic test for Chagas disease, a risky infection threatening an increasing portion of the population, could be just what’s needed in resource-poor regions where the infection is endemic.
The test could also help stem the infection’s advance into other counties where people are being infected with increasing frequencies, said Steve Reed, CEO and founder of the Infectious Disease Research Institute, which collaborated with Seattle-based InBios International to
develop the point-of-care test.
Although commercial laboratory-based tests are available to identify and track Chagas, most people are unaware of the infection or that they may be carrying it, Reed said.
Lab tests are available through Abbott Laboratories and Ortho Clinical Diagnostics, and Ortho launched the first test to screen blood donors for Chagas in 2006.
However, commercial laboratory tests have been primarily adopted to prevent the spread of infection in blood banks, Reed said, and that’s only a small percentage of the total population that can become infected.
The new point-of-care test is vitally important because it makes testing available and affordable to a broader swath of the population, said Robert Gilman, an infectious disease physician at Johns Hopkins Bloomberg School of Public Health, who has been conducting research into the prevalence, diagnosis, and treatment of Chagas infection for decades.
The test would enable “screening for a disease we estimate in some populations to be more than 4 percent prevalent,” he said.
The antibody-based rapid test can be used in the clinic or in the field, and it will be available for less than $1 per test while producing a result in about 20 minutes, Reed said. It uses a fusion antigen developed and patented by IDRI, which develops antibody proteins used in diagnostic
tests for neglected infections and diseases.
In clinical studies, the InBios in vitro rapid test demonstrated greater than 95 percent sensitively and specificity in both endemic and nonendemic
populations, according to its developers.
The point-of-care test may be especially important in the early detection of Chagas infection for the prevention of cardiomyopathy and for the detection of prenatal infection due to congenital transmission, which can be as high as 10 percent of infected mothers in some countries, Gilman said.
“POC testing is crucial for prenatal care of Hispanic [women] from endemic countries,” he said. “Crucial also is that it can be done in doctors’ offices similar to a pregnancy test.”
InBios recently received 510k clearance for the rapid test from the US Food and Drug Administration, making it the first point-of-care diagnostic test for Chagas disease available in the US.
Reed said that the FDA clearance gives the test “credibility not only in the US, but also globally,” which is particularly important for countries such as Brazil, Bolivia, Colombia, Peru, and Argentina where the parasite causing the infection is endemic.
Chagas disease was first described in 1909 by the Brazilian scientist Carlos Chagas.
Caused by the parasite Trypanosoma cruzi, also called the kissing bug, the infection is getting increasing attention from world and national health agencies. Globally, an estimated 6 million to 7 million people have Chagas, according to the World Health Organization.
Most live in Latin America, where the parasite is endemic, but they carry the infection with them to other countries when they travel.
Up to 30 percent of chronically infected people develop cardiac alterations, and up to 10 percent develop “digestive, neurological, or mixed alterations which may require specific treatment,” according to WHO.
Human infection can occur when a bug called a triatomine carrying T. cruzi bites a person then defecates on the wound. T. cruzi in the bug’s feces can then enter the person’s body through mucous membranes or breaks in the skin. An initial acute phase of Chagas continues for about
two months after infection. Symptoms are often absent, or they are mild and unspecific. During a subsequent chronic phase, the parasites are hidden mainly in the heart and digestive muscles. Up to 30 percent of patients suffer from cardiac disorders and up to 10 percent suffer from
digestive, neurological, or mixed alterations, according to the WHO.
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