The Centers for Disease Control and Prevention is advising healthcare providers to consider human plague as a diagnosis for patients presenting with classic plague symptoms—such as fever, abdominal pain and vomiting—who have traveled in the Western U.S. and who have had contact with rodents, rodent habitat or sick domestic animals.
There have been 11 cases of the plague and three related deaths since April, the CDC reports. The majority of those affected were residents in Western states. There are two residents of Georgia who contacted the disease during exposure at or near Yosemite National Park in California's Sierra Nevada mountain range. The disease was also caught by a California resident whose exposure was also traced to the Yosemite area.
The National Park Service reported that a squirrel captured at a campground outside of Yosemite tested positive for the plague. This prompted the California Department of Public Health to treat “rodent burrows” with a flea-killing insecticide.
Plague is carried by squirrels, chipmunks and other small rodents and is spread by their fleas. But transmission between people is rare.
“The California Department of Public Health and Yosemite National Park were very proactive in their campaign to educate visitors about plague,” California State Health Officer Dr. Karen Smith said in a news release. “Warnings issued in California regarding plague were useful all the way across the country in Georgia. Those warnings helped the patient get the prompt medical attention necessary to recover from this illness.”
Between 2001 and 2012, there have been one to 17 cases of plague a year with the median number being three, according to the CDC. This year, nine of the 11 cases have been among males between ages 14 and 79, with a median age of 52.
There are three common forms of the plague: Bubonic (80% to 85% of cases) infection of the lymph nodes, septicemic (10%) infection of the blood, and pneumonic (3%) infection of the lungs. The death rate for untreated plague is between 66% and 93%, but antibiotic treatment lowers mortality to 16%, according to the CDC.
The National Institute of Allergy and Infectious Disease describes pneumonic plague as the “least common but most serious form of the disease.” The NIAID noted its research contributed to a recent Food and Drug Administration decision to license the antibiotic ciprofloxacin to treat pneumonic and septicemic plague.
The CDC says the 11 cases confirmed this year are both bubonic and septicemic.
The research was part of NIAID's biodefense program, which conducts research “while maintaining the ability to respond rapidly to emerging public health threats, whether natural or bioterror-related,” the NIAID stated in its fiscal 2016 budget request.
For fiscal 2016, President Barack Obama has requested $1.36 billion for the NIAID biodefense program, which is $94.5 million more than what was appropriated for fiscal 2015.
This spring, the FDA also approved using the antibiotic moxifloxacin (Avelox) to treat pneumonic and septicemic plague.
