Here is a glimpse into the future of global public health: a credit-card sized piece of paper is dunked into a liquid sample at a health clinic in a developing nation, quickly telling a doctor or nurse whether a malnourished child with diarrhea is infected with a virus, a bacteria, or a parasitic protozoan.
Gastrointestinal ailments may sound like a small matter in the industrialized world, but in millions of remote villages in developing nations, food, and waterborne illnesses are potentially deadly matters. According to the WHO, diarrheal diseases are among the top 10 causes of death; and they are the second biggest killer of children under the age of 5.
Rapid diagnosis can mean fast, appropriate treatment. This is the quest of Shannon Weigum, an associate professor of biology at Texas State University. Her laboratory is merging principles of biochemistry and materials science to create a miniature, highly portable, rapid-detection tool for diarrheal illnesses. Her hope is that this tool could someday make a major impact on global health.
Weigum’s first diagnostic targets are noroviruses, which cause more than half of the foodborne illnesses in the U.S. Health data shows that noroviruses are the most common cause of diarrhea in adults and the second most common cause in children. The tests have been expanded to detect bacteria and protozoan parasites.
The overall goal is to make diagnostic testing available where it previously was not. To be practical for remote clinics in undeveloped areas, though, lab tools have to be inexpensive as well as highly portable. Poor countries lack medical infrastructure and skilled personnel to operate the sophisticated diagnostic tools found in large urban medical centers.
Imbued with nanoparticles and using microfluidics, the paper cards interact with specific bacteria or viruses to quickly, accurately identify diseases. A faster diagnosis means healthcare workers can move beyond treating symptoms and attack the disease.
The ‘sample to answer’ test provides results in about 20 minutes. It utilizes smartphone technology as an analytical instrument. Now, instead of reading the sample with the naked eye the phone acts as an optical instrument to read the light-based signal.
