Plague Bacteria Eyed in Calif. Campground
The bacteria that caused the Black Death and wreaked havoc throughout Eurasia in the Middle Ages was identified last week at the Doane Valley Campground on Palomar Mountain in San Diego County, Calif., in six ground squirrels that tested positive for it, according to the Voice of San Diego.
Signs are posted around the campground where the plague has been confirmed, advising campers to resist the urge to handle or feed wild or dead animals, watch for rodent burrows before setting up camp and keep household pets at home if possible. If campers do bring pets, they are advised to use flea control.
County officials said there have been no cases of locally acquired plague reported in San Diego County. The chance of a human contracting the disease is slight, officials said. The plague is transmitted by infected fleas, and the squirrels tested were flea-free.
About five to 15 human cases of the plague are reported in the U.S. each year, 14% of which are fatal, according to the Center for Disease Control and Prevention.
Rodents in Colorado, Arizona, Utah and Los Angeles County have been wiped out by the plague this summer.
“We’re not saying, though, that plague in the United States will cause another Black Death,” said David Engelthaler, director of programs and operations for TGen North, a pathogen genomics laboratory in Flagstaff, Ariz. “Those were different times; people lived in different conditions, different sanitation. They didn't understand germ theory. They didn't know how to treat disease.”
Now that people don't live in such squalid conditions, where human fleas run rampant, the plague is a much less fearsome disease.
The bubonic plague, the most common of three forms the plague can assume and the type found in the squirrels, is now highly treatable through the use of antibiotics. It has a much longer gestation period and infects the lymph nodes in the neck, armpit or groin, inflating them into large, painful cysts called buboes. The other two forms, septicaemic, which causes bleeding in the skin and other organs, and pneumatic, which infects the lungs and can be spread through water droplets projected by coughing, are more fatal.
When a flea is infected with bubonic plague, the bacteria, called Yersinia pestis, forms a plug in its stomach, forcing it to starve. The flea will continue to bite into new hosts in attempts to satiate its hunger, but instead vomits the plague-tainted blood into the wound, infecting the host. The pests favor rodents like the prairie dogs, field mice and ground squirrels like those affected this summer.