First Swine, Now Squirrels

On April 2, a ground squirrel from the Doane Valley Campground on Palomar Mountain tested positive for plague, the “black death” disease that ravaged Europe and killed millions during the 14th Century.

“The number of positive squirrels varies from year to year, but finding six to ten in a season would not be unusual,” says Chris Conlan, supervising ecologist with County Vector Control. According to Conlan, plague-infected squirrels only seem to be found at the higher elevations in San Diego County, most often during the summer months.

“This recent [squirrel find] is a bit on the early side,” notes Conlan. Local campgrounds are an ideal place for testing squirrels for plague, due to the moderate to high squirrel populations. However, a busy campground also means an increased risk of squirrels interacting with humans. To make matters worse, campers have been known to unwittingly exacerbate the problem.

“By feeding the squirrels, they may allow an area to support a much higher population than it normally would,” says Conlan. “If there are more squirrels running around, it just increases the odds of a disease being able to multiply and spread.” Conlan recommends that campers avoid contact with squirrels and to keep their food items in an area where squirrels cannot get to them.