Squirrels and their fleas can carry plague (photo: Getty Images)
For the first time since 2006, a Californian has been diagnosed with plague, a deadly, infectious bacterial disease called Yersinia pestis.
The announcement by the California Department of Public Health (CDPH) that a child in Los Angeles County was likely infected while camping in Yosemite last month came just days after an adult died of plague in Colorado. The family stayed at the Crane Flat Campground.
The child is reportedly recovering while investigators trace the family’s contacts during the incubation period and do an environmental evaluation in the Stanislaus National Forest. There have been 42 confirmed human cases since 1970. Nine were fatal. There has been no report of human-to-human infection in California since 1924.
Plague is carried by fleas and their hosts: squirrels, chipmunks and other wild rodents. When the animal dies, the fleas look for new homes. They usually aren’t humans. Plague-infected animals are more likely to be running around in the foothills and mountains than the coastal areas. They avoid the desert and Central Valley.
Plague was detected in animals in seven counties last year: El Dorado, Mariposa, Modoc, Plumas, San Diego, Santa Barbara and Sierra.
Symptoms of the most common form of plague, bubonic, include high fever, chills, nausea, weakness and swollen lymph nodes. Septicemic plague lacks the swelling and seems more like flu, and the least common, pneumatic, can be spread through coughing. Symptoms usually appear 2-6 days after exposure.
Domestic animals can acquire plague (pdf). Dogs don’t usually show symptoms but cats do. They both can transport the fleas.
Plague is responsible for three great pandemics, in AD 541, 1347 and 1894. The first, known as the Justinian Plague, hit central Africa, Egypt and the Mediterranean. The second, famous as Black Death, killed one-third of Europe (20 million people) in five years during the 14th Century. It had already laid waste to China, India, Persia, Syria and Egypt. The third started in China before sweeping through India on its way to the rest of the world.
Better sanitation and antibiotics for the bacteria, finally identified during the third pandemic, have reduced the threat substantially.