A public health crisis has infiltrated our North American sanctuary, a contagion so swift and indiscriminate that a moment’s contact has fatal consequences.

Whenever a new strain of the virus breaks out, those appalled by it raise alarms and issue calls to action. Some even suggest restricting access to that which carries the deadly plague. But critics accuse them of fearmongering, of using tragedy to advance their agenda, of assaulting the freedom of law-abiding people.

This summer, when a black man fell victim in a high-profile case that raised questions about public safety, people paid attention for more than the typical day or two — even taking to the streets. But that was rare.

Then more cases popped up. On Oct. 22, a man opened fire in Ottawa before being fatally shot by security inside the Parliament of Canada. On Oct. 24, the bullets spread like a virus in the close confines of a high school cafeteria in the Seattle area when a student opened fire on family and friends. Four died — including the shooter — and two more are hospitalized.

A bullet-borne virus is infecting the land, and carriers often don’t even have a fever to show for it. There have been more deadly shootings since — Oct. 25 in Detroit, Oct. 26 in Chicago, Oct. 27 in Ypsilanti — but a remarkable calm blankets North America.

The bigger danger gripping the public mind appears instead to be Ebola, an exotic disease of African origin spread only by direct contact with bodily fluids of those who are infected. Containing a viral outbreak is important, and impoverished West African nations can use all the assistance wealthier nations can supply.

Yet an outbreak of gun violence, which carries a far higher death toll and has been on the ground in virtually every corner of North America for much longer, brings a complacent response.

While some call for drastic measures to choke off Ebola’s assault, many take an opposite approach to a proliferation of firearms and ammunition that goes far beyond the needs of hunting and sport.

The problem isn’t guns, say some opponents of gun control, it is a lack guns. After the 2012 school shootings in Newtown, Conn., the National Rifle Association suggested placing armed guards in every school.

In October, as teenagers with severe head wounds lay in critical condition near Seattle, the NRA kept up the pressure on any politician seeking any curbs on firearms — at last count spending eight times more on political advertising this year than it did in 2006.

The Centers for Disease Control reports there were 32,351 firearms deaths in the U.S. just in 2013. The World Heath Organization reports the global Ebola death toll is 4,951. Let’s keep taking our temperature.