(USA TODAY) -- The discovery of one plague-infected squirrel in Southern
California is not the beginning of the Zombie Apocalypse. It's merely an
indication that our public health system is working smoothly.
are about seven cases of the plague each year in the United States,
according to the Centers for Disease Control and Prevention. Most are in
the West, where the Yersinia pestis bacteria that causes plague lives in rats, squirrels and other rodents and the fleas that infest them.
the Black Death may have wiped out one-third of Europe's population in
the 1300s, it couldn't happen today. Antibiotics are a very effective
treatment. Today about 90% of plague victims who get prompt medical
The discovery of the infected squirrel was
routine and part of ongoing public health surveillance, says Ken Gage,
chief of CDC's flea-borne diseases section in Fort Collins, Colo. States
where plague is known to exist "are quite good at responding quickly,"
In the United States, plague is regularly found in the
West. Since 1970, cases have been reported in Arizona, California,
Colorado, Idaho, Nevada, New Mexico, Oregon, Texas, Utah and Washington.
States where the plague exists began testing rodents for the disease
the 1930s and today have effective programs in place to control it, Gage
The plague-infected squirrel in Wrightwood, Calif., was
found July 16 by the California Plague Surveillance and Control Program.
As soon as tests for plague came back on Wednesday, health officials
closed three nearby campgrounds in the Angeles National Forest to
protect campers. They also posted notices in the area to warn residents
to avoid dead animals that might carry fleas, Gage said.
officials will now track down the squirrel's burrows and dust them for
the fleas that actually carry the plague bacteria. The campgrounds will
be reopened after testing shows they're plague-free.
The only way
to get plague is to be exposed to infected fleas or rodents or to have
the plague bacteria get into an open wound or cut, the CDC says. With
modern housing and pest control, that's a lot less common than it was in
1350 when entire villages died from the disease.
About 80% of
plague cases in the United States occur when people come into contact
with infected fleas jumping from dead animals or animal burrows to
humans, Gage said.
Last summer, a 7-year-old girl was camping
with her family in Colorado and got the plague from a dead squirrel. The
animal-loving girl asked her parents if she could bury the squirrel.
Her mother said no, but the child hid the squirrel in her sweatshirt
anyway. Doctors found insect bites on her torso and think fleas on the
carcass bit her. After weeks in the hospital she survived.
15% to 20% of cases are in hunters or trappers. "That could be hunters
who have shot rabbits or trappers who have trapped infected bobcats,"
CDC's Gage says. In one case several years ago, a National Park Service
wildlife biologist died from the plague after handling a mountain lion.
He had fitted it with a radio collar. When the animal later died, the
biologist found the carcass and took it back to skin it, Gage says.
tiny proportion of cases come when people are in contact with infected
cougars, bobcats and domestic cats. "Felines are very susceptible to
plague, and they can spread the disease to people through coughing and
bites," Gage said. However, there have only been 30 such cases since
1977, he said.
The plague first arrived in the United States
around 1900, in rat-infested steamships arriving from infected areas,
most likely Asia. There were several plague outbreaks across the West
early in the century. The last major one was in Los Angeles in 1924 and
Plague symptoms include fever, chills, headache, weakness and swollen and tender glands in the neck, underarms or groin.