Health & Science

Resurrecting an ancient virus

French researchers have revived a dormant and previously unknown virus from a 30,000-year-old sample of Siberian permafrost. The pathogen poses no threat to humans, but its zombie-like return to an infectious state demonstrates the remarkable durability of microbes and raises the question of whether unknown, disease-causing viruses from some ancient era might be locked in ice. “[This] is a good demonstration that the notion that a virus could be ‘eradicated’ from the planet is plain wrong, and gives us a false sense of security,” Jean-Michel Claverie of the Mediterranean Institute of Microbiology tells Smithsonian.com. The virus, Pithovirus sibericum, is between 10 and 100 times larger than an average-size virus, and its 500 genes give it far greater genetic complexity than the common influenza virus. All viruses require host cells to reproduce, and they exist in an inert state in between reproductive cycles, much like a plant’s seed does. In this instance, researchers thawed a sample of frozen soil taken from 100 feet underneath the surface, then placed it on a petri dish containing amoeba colonies. The resuscitated virus was absorbed by the amoebas and then began making copies of itself until it split open its hosts, killing them.

Sharks with cameras

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Call it reality television, shark style. Scientists have attached video cameras to the pectoral fins of more than 30 sharks, allowing them to observe how they move and hunt and to better understand the predators’ ecological role. “We’re seeing behaviors that we simply couldn’t see before,” Hawaii Institute of Marine Biology researcher Carl Meyer tells HuffingtonPost.com. The new recording system goes far beyond traditional tagging to include not only cameras, but also sensors that measure water depth and temperature, acceleration, and the magnetic field around the shark. To attach the equipment, gutsy researchers flipped the sharks onto their backs, plunging them into a calm, trance-like state called “tonic immobility.” The project studies five species—tiger, Galapagos, sandbar, prickly, and bluntnose sixgill sharks—and has already delivered insights into how sharks cover vast expanses of ocean. The researchers have footage of sandbar, blacktip, and hammerhead sharks joining together into a tornado-like formation to avoid being preyed upon by tiger sharks. The data, Meyer says, “has really drawn back the veil on what these animals do.”

Suicide in the military

The tremendous stress of combat in Iraq and Afghanistan isn’t the only reason for the marked upsurge in military suicides over the last decade. That’s the key finding of a massive study by the National Institute of Mental Health encompassing observations on 1.6 million military personnel. “The story is not so simple as ‘war is hell’ and you send people to war and bad things happen to those people,” epidemiologist Michael Schoenbaum tells The Wall Street Journal. People who enlist in the military, researchers found, are more likely to have a history of depression and impulsive anger, which makes them more likely to act on suicidal urges. Drawing on mental health data going back to 2004—including drug test results and training records—as well as interviews with soldiers, researchers found that one third of soldiers who have attempted suicide had a mental disorder before enlisting and that a quarter of active-duty soldiers who have never deployed to combat have some sort of psychiatric disorder.

A convergent global diet

People around the world are buying and eating the same foods, raising concerns about the resilience of the world food supply. A new study drawing on 50 years of data from the United Nations’ Food and Agriculture Organization has found that fewer crops are feeding the world, leaving us increasingly vulnerable to the depredations of disease, pests, and climate change. “As the global population rises and the pressure increases on our global food system, so does our dependence on the global crops and production system that feed us,” Luigi Guarino of the Global Crop Diversity Trust tells BBC.com. Wheat, for example, is now a key food in more than 97 percent of countries, and soybeans have risen from relative obscurity to become “significant” in the diets of almost three quarters of nations. Rice, corn, potatoes, and sugar have all expanded their footprints, elbowing out such traditional crops as millet, rye, sweet potatoes, and cassava. Researchers note that the homogenization largely reflects the spread of the Western diet, which has likely contributed to the rise in global obesity and the resulting increase in diabetes and heart disease.