When major diseases begin to spread, time is of the essence. The African Ebola outbreak, for example, lasted from 2014 to 2016 and killed more than 11,000 people in six countries, writes the BBC. However, months before the epidemic took hold, doctors reported symptomatic patients in three locations separated by more than 60 kilometers. Had healthcare workers identified these and other hot spots earlier using rapid diagnostic testing, they could have minimized the number of people exposed and fast-tracked treatments, reports The Lancet.
As one of the most important healthcare technology advances in recent years, rapid diagnostic testing analyzes samples of bodily fluid for either genetic material from bacteria, viruses or other foreign substances, or it identifies proteins produced by a person’s natural immune response to pathogens. These point-of-care tests can detect malaria, HIV, Hepatitis B, influenza, respiratory infections and other diseases within minutes. These small, portable healthcare kits are ideal not only for remote clinics, but also for military defenders facing bioterrorism and for astronauts that may need to identify diseases while traveling in space.
Lab on a Stick
Rapid diagnostic testing replaces lab microscopy — where samples are analyzed under a microscope — with vials, wands, cards or tiny cassettes. Home pregnancy tests are a good analog. Minutes after being placed in a stream of urine, a window on the plastic wand shows an indicator color, symbol or word that confirms whether a woman is pregnant or not. The results appear because the test strip inside the wand already contains a substance that binds to the specific hormone that increases after conception, according to the Mayo Clinic. Similar techniques can be used to detect disease.
The first quick test to detect Ebola, called ReEBOV Antigen Rapid Test, involves placing a drop of blood onto a strip of paper. The strip is dipped into a tube containing substances that bind to immune-response proteins produced by the body when the Ebola virus is present. If two lines appear on the strip after 15 minutes, it means the sample is positive for Ebola. Approved in 2015 by the World Health Organization (WHO), the test greatly increased the ability of healthcare workers to identify sick patients and treat them quickly. Since then, other testing platforms have emerged, including OraQuick, which also senses proteins and works via a dipstick, and the GeneXpert, which is designed to detect the presence of genetic material from the virus.
In regions where the Ebola virus and malaria overlap, the ability to diagnose disease quickly is critical. Early in the infection, patients afflicted by either disease experience fever, headache, chills, muscle aches and vomiting. Thankfully, a rapid test exists for mosquito-borne pathogens, as well. It comes in the form of a thin, plastic cassette about the size of a stick of gum, according to World Health Organization (WHO). Inside is a strip of paper treated with substances that bind to proteins and other biological products related to the malaria pathogen. On top of the cassette are two holes and a window. The clinician pricks blood from a finger and mixes it with a chemical that destroys cell walls, releasing more parasite proteins. The health worker adds the treated blood to one hole and a flushing agent to the other hole. Blood then moves across the paper strip. If parasitic proteins are present, they’ll bind to the substances on the strip and produce two lines, indicating the presence of malaria within 20 minutes.
Defending Against Bioterrorism
Disease epidemics are not limited to countries in Africa. In a 2016 congressional hearing, former Director of National Intelligence James Clapper testified that infectious diseases and inadequate medical countermeasures would continue to pose threats to U.S. citizens. Biological warfare also poses a threat. In 2017, the Independent reported that four soldiers who had defected from North Korea had antibodies in their blood that fight off anthrax, a deadly bacterium that has been used in the past for bioterrorism. The alleged presence of these antibodies suggested that these soldiers may have been exposed to anthrax or may have been vaccinated for it.
The Department of Defense is working with government researchers and private labs to develop rapid diagnostic testing that can quickly sense biological threats similar to anthrax and treat them. In January 2019, scientists at the government-funded Sandia National Laboratories reported that they had developed a portable device called SpinDx that could analyze blood or bodily excretions for proteins and genetic material that indicate the presence of viruses, bacteria, toxins or even exposure to chemical agents. Later that same year, the Department of Defense’s PRISM (Platforms for Rapid Integrated Solutions for Medical countermeasures) office awarded the private company Ology Bioservices two contracts to develop the next-generation of responses to chemical and biological threats, reports the Associated Press.
Disease’s Next Frontier
Arguably, space represents the ultimate challenge. Microgravity seems to suppress the human immune system, while at the same time making some bacteria more virulent, reports NASA. As humans embark on future missions to the Moon and Mars, they’ll need to detect and treat health problems as soon as possible.
In 2018, NASA selected the Miami-based company One Milo as one of three winners of its iTech competition. The company developed a handheld device that uses blood, urine or saliva to test for disease and then sends the data wirelessly to a smartphone app. The NASA subcontractor Cellmic, which in 2019 was acquired by Now Diagnostics, has also developed a sensor platform that uses a smartphone’s camera and computer to analyze bodily fluids for the presence of pathogens.
Worldwide, diseases are on the rise. Since 2004, reports of dengue, Zika, Lyme and the plague — which are all transmitted by mosquitoes, ticks or fleas — have tripled, according to the Centers for Disease Control. And since 1991, 30 completely new infectious diseases, including Ebola, HIV and Hepatitis C, have been discovered. Finding news way to respond to outbreaks quickly, whether natural or human-caused, will thwart life-threatening pandemics and save lives. Rapid diagnostic testing devices may be among the most critical healthcare technology advances to mature in coming decades. These inventions can defend humans against killer pathogens lurking in the most remote jungles to those made more virulent in the far reaches of space.