Some companies have simplified the problem by avoiding blood altogether. LabCorp recently commercialized a biomarker test that analyzes colon cells in stool for the chemical signatures indicative of colorectal cancer. “The stool is in intimate contact with the lining of the colon, so it becomes much more highly populated with these rare molecules than would get into the bloodstream from colon cancer,” says Barry Berger, chief medical officer of Exact Sciences, a Madison, Wis.–based biotechnology company that developed the test technology.
In time, scientists are confident that they will eventually crack the more difficult problem of finding distinct disease signatures in the noisy data. “The evolutionary process, being complex and unknown, does not always give us an easy route,” Berger notes, “but it definitely gives us lots of opportunities.”
Satellites Diagnose Disease Outbreaks
Space-based data are helping to track and predict the spread of deadly diseases
By Katherine Harmon
Many contagious diseases spread through carriers such as birds and mosquitoes. These vectors in turn move with heat and rainfall. With this in mind, researchers have begun to use satellite data to monitor the environmental conditions that lead to disease. “Ideally, we could predict conditions that would result in some of these major outbreaks of cholera, malaria, even avian flu,” says Tim Ford of the University of New England at Biddeford and co-author of a paper on the subject published this past September in Emerging Infectious Diseases.
Satellite data have already been used to map the advance of the H5N1 avian influenza in Asia. The domestic duck, a common inhabitant of Southeast Asia’s rice paddies, is one of the main carriers of the disease. Xiangming Xiao, associate director of the University of Oklahoma’s Center for Spatial Analysis, uses satellite images to map agricultural patterns in the region. These maps show where the ducks are most likely to live and thus where the avian influenza is most likely to spread.
Migratory birds also carry the virus, but their travel patterns are more difficult to predict. Xiao and his colleagues combine the satellite imagery with satellite-gathered surface-temperature data to estimate the birds’—and thereby the virus’s—trajectory. Computer models then link these environmental drivers to the spread of the flu in human populations.
Of course, not all of the work can be outsourced to orbiting observatories. Xiao says that judging the severity of avian flu’s spread from satellite imaging required knowing details about the human populations as well—for instance, how likely certain communities were to raise ducks for poultry consumption. “Satellite monitoring has a capacity to provide consistent observation,” Xiao says. “On the other hand, the in situ observations are still very, very important, so the key is to combine those together. That is a real challenge.”
More Ideas to watch
By Melinda Wenner
Emergency technicians could prevent up to 35 percent of prehospital trauma deaths if they had better and cheaper ways to prevent blood loss. Now a University of Maryland–affiliated start-up called Trauma Solutions has developed a synthetic hydrogel that can clot blood by prompting the body to make fibrin, a protein that seals wounds and stops bleeding. Future iterations could simultaneously release such medicines as antibiotics and painkillers. Each application will cost about $5, compared with some natural blood-clotting substances that cost upward of $500.
Liver damage is a major side effect of HIV/AIDS and tuberculosis drugs, yet few developing countries have enough trained scientists or equipment to monitor it. Nonprofit Cambridge, Mass.–based Diagnostics For All has developed an inexpensive fingernail-size device made almost entirely of paper that monitors liver damage using a single drop of blood. Channels in the paper guide blood to regions that change color depending on the levels of two damage-related liver enzymes.