"In the most recent global burden-of-disease study, diarrheal disease accounts for the loss of more disability-adjusted life years than any other infectious disease, and cryptosporidiosis is the second leading cause of diarrheal illness." Crannell said. "Anybody, if it's not treated, can get dehydrated to the point of death.
"There's a lot of new evidence that even with asymptomatic cases or cases for which the symptoms have been resolved, there are long-term growth deficits," he said.
Current specialized tests that depend on microscopic or fluorescent analysis of stool samples or polymerase chain reactions (PCR) that amplify pathogen DNA are considered impractical for deployment in developing countries because of the need for expensive equipment and/or the electricity to operate it.
The Rice test depends on recent developments in a recombinase polymerase amplification (RPA) technique that gives similar "gold standard" results to PCR but operates between room and body temperatures. In Rice's experiments, samples were prepared with a commercial chemical kit that releases all the DNA and RNA in the small amount of stool tested. The purified nucleic acids are then combined with RPA primers and enzymes tuned to amplify the pathogen of interest, Crannell said.
"If the pathogen DNA is present, these primers will amplify it billions of times to a level that we can easily detect," he said. The sample is then flowed over the detection strip, which provides a positive or negative result.
The RPA enzymes are stable in their dried form and can be safely stored at the point of care without
|Contact: David Ruth|