Two additional squirrels have tested positive for the agent of plague, Yersinia pestis, in the Palomar Mountain area, prompting environmental officials to protect themselves and their pets when they hike and camp.

Public domain image/Jon Sullivan
Public domain image/Jon Sullivan

The squirrels were trapped last week in the Doane Valley Campground area. “People need to remember not to feed or play with squirrels when you come across them outdoors,” said San Diego County Environmental Health Director Liz Pozzebon. “Don’t play near squirrel burrows or set up your tents around them, and report dead squirrels to camp rangers.”

Environmental Health Vector Control crews have posted warning signs and dusted squirrel burrows in the area to kill the fleas that can transmit plague from squirrels and rodents to people.

Plague is found in animals throughout the world, most commonly rats but other rodents like ground squirrels, prairie dogs, chipmunks, rabbits and voles. Fleas typically serve as the vector of plague. Human cases have been linked to the domestic cats and dogs that brought infected fleas into the house.

People can also get infected through direct contact with an infected animal, through inhalation and in the case of pneumonic plague, person to person.

Yersinia pestis, the bacterial agent of plague,  is treatable with antibiotics if started early enough. There are three forms of human plague; bubonic, septicemic and pneumonic. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page