Child who visited Yosemite National Park comes down with the plague

(CNN)Every year, picturesque Yosemite National Park gets about 4 million visitors. But one arrival this summer is definitely not welcome: the plague.

California's Department of Public Health and the national park announced Thursday that a child who visited nearby Stanislaus National Forest and camped at Yosemite's Crane Flat Campground in mid-July had contracted the plague.

That child is recovering, and no other members of the camping party have reported any related symptoms.

By Greg Botelho, CNN

Updated 0554 GMT (1254 HKT) August 7, 2015

2 deadly plague cases this year in Colorado

Contagious and potentially deadly viruses are not new for Yosemite, where throngs of people flock annually to enjoy breathtaking rocky cliffs, refreshing river waters and dense forests.

In 2012, for instance, three park visitors died after contracting hantavirus.

Yet plague cases are rare not just in Yosemite, but across the United States.

The disease killed millions centuries ago, and -- while it can be treated with modern medicine such as antibiotics and antimicrobial -- it's never gone away.

Adult dies of plague in Colorado

The Centers for Disease Control and Prevention reports that the United States has about seven annual cases, over 80% of which have been in the bubonic form.

There have been three cases reported so far in 2015, which is in line with those numbers. The other two happened in Colorado and both resulted in deaths, one being a teenager in Larimer County and the other an adult in Pueblo County, as announced Wednesday by the local health department.

The Yosemite case is California's first instance of human plague since 2006, according to state health officer Dr. Karen Smith, when there were three cases in Mono, Los Angeles and Kern counties. There have been 42 such cases in the state since 1970, of which nine proved fatal.

"Although this is a rare disease, people should protect themselves from infection by avoiding any contact with wild rodents," Smith said.

a map shows reported cases of human plague in the uS  from 1970 to 2012. Nearly all cases occurs in the western US., for reasons that are not entirely understood.