On Thursday, authorities announced that a child who camped at Yosemite's Crane Flat Campground and visited other places nearby Stanislaus National Forest in mid-July had contracted plague. He has been sent to hospital.

California's Department of Public Health and the national park said no other family member has fallen sick. The officials also affirmed that the child is recovering. On annual basis, around four million visitors come to Yosemite National Park.

The bacterium that causes the plague can sometimes infect the blood owing to which the hands, feet, nose and lips can become gangrenous and black. If treated with antibiotics then this form of disease is always not fatal.

Experts have affirmed that plague is being caused by rodents like squirrels. Plague is spread when fleas carries the disease from a dead rodent to other animals or humans. Officials said that plague does not get passed between humans; it can happen in extremely rare cases.

Authorities concerned were of the view that they have been monitoring the situation and warning people to be on guard against plague. It is not the first time for Yosemite to witness such harmful viruses, but then also a number of people com there to enjoy dense forests, rocky cliff and water.

In comparison to other health problems, plague is rare not only in Yosemite, but in the US as well. As per the Centers for Disease Control and Prevention, the US has around seven cases and more than 80% of them have been in the bubonic form.