The mad cow-like infectious disease that can turn the brains of deer, elk, and moose into Swiss cheese is spreading faster than ever before, and scientists fear it could soon infect humans. Known as chronic wasting disease, or CWD for short, the infection is spread by zombie-like prions, which can’t be killed and travel throughout an animal’s body, causing a brain-destroying, progressively progressive neurological condition.
The discovery of a new strain of the disease raises alarms in the US, especially in Canada, where the government has moved quickly to combat the outbreak. It has closed hunting in the affected areas, ordered road-killed deer to be tested, and imposed strict quarantines on herds with close epidemiological links. It has also announced plans to set up a national network of surveillance and monitoring centers, including one amid the deer-hunting season in Minnesota.
Researchers believe the spread of CWD is accelerated by how people trade deer and other hoofed mammals — and by the fact that the disease can be transmitted through ticks. Several studies have found that single deer ticks can contain transmission-relevant loads of disease-causing prions, and a healthy deer could easily swallow one during social grooming. The tick then would transmit the disease to other deer and people who eat the meat.
Moreover, the diagnostic tools available for detecting CWD only work on dead animals and can take days or weeks to get results. So even if hunters and taxidermists are testing every deer they harvest, it can be months or years before anyone knows a herd has been infected with the deadly pathogen.
The first known case of the disease in Manitoba was found last fall near Dropmore, a small town in central Manitoba, just a stone’s throw from Saskatchewan’s border. The mule deer, spotted by a wildlife health surveillance team, was thin and behaving oddly. It was euthanized and then driven 150 kilometers east to a nondescript row of sheds on the outskirts of Dauphin, Manitoba’s capital city. There, the deer would test positive for CWD — the province’s first case in two decades of sampling, testing, and surveillance.
But the finding is a serious wake-up call to those who love and enjoy venison and other wild game meats. If the current spread of the disease continues, people will inevitably be eating infected venison for much longer than they probably want to imagine. If that happens, it will be because we weren’t ready for the inevitable. And that’s a very, very scary thought.
