By ELIZABETH LIU Senior Staff Writer
Bubonic plague, a disease mostly associated with the 14th century epidemic that ravaged the populations of Europe and Asia, may be on the rise.
Since April of this year there have been at least 11 reported cases of plague, a dramatic increase from the five that were reported last year. The most recently reported case was diagnosed in a teenage girl from Oregon.
State and local health officials in Oregon suspect that the girl was infected when she went on a hunting trip near the city of Heppner with her friends on Oct. 16. She was reported to have fallen ill on Oct. 21 and was hospitalized soon after. Since then there have been no other reported cases.
Bubonic plague, which affects the lymph nodes, is one of the three types of plague caused by the bacterium Yersinia pestis. The other two, septicemic plague and pneumonic plague, infect the blood and lungs, respectively. Plague symptoms generally develop within one to four days after exposure. They include fever, chills, headache, weakness and a bloody or watery cough.
The plague is typically spread by flea bites. The bacterium that causes the disease is carried by warm-blooded animals, such as chipmunks, squirrels and rats. When the animal becomes sick and dies, its fleas can carry the infection to other mammals by biting them. Fortunately, it is extremely unlikely for the plague to be transmitted from person to person.
While all three types of plague — bubonic, septicemic and pneumonic — are relatively rare diseases, bubonic plague is the most common; more than 80 percent of all plague cases reported in the U.S. between 1900 and 2012 have been bubonic. It is mainly characterized by a high fever, lethargy and swollen lymph nodes near the neck and under the jaw. The swollen lymph nodes could also spontaneously erupt and drain.
Currently there are no vaccines for the plague, but it is treatable with antibiotics if caught early on. With treatment, the mortality rate is about 16 percent.
However, if left untreated, 66 to 93 percent of infections end in death.
Federal health officials have been perplexed by the increase in plague cases this year — on average, there are about seven cases of plague per year, but since April 1, there have been at least 11 reported cases, three of which were fatal, according to the Centers for Disease Control and Prevention (CDC).
These recent cases have afflicted residents in western and southern states, such as Arizona, California, Colorado, Georgia, New Mexico, Oregon and Utah. Two of these cases have been linked to Yosemite National Park, which has led to the temporary closure of a few campgrounds.
While the rise of bubonic plague cases still remains a mystery, doctors and health officials say that there is no need to panic. There are a lot of practical, preventative measures that hunters, hikers and campers should take in order to reduce their risk, especially if they are traveling in one of the affected states.
Since the plague is usually spread by rodents and fleas, health authorities recommend wearing long pants, using insect repellent, making sure pets have been receiving regular flea treatments and avoiding sick or dead rodents.