An Oregon teen was hospitalized on Oct. 24 following a bubonic plague diagnosis. The 16-year-old girl is believed to have caught the plague from a flea bite while on a trip, which marked the 16th documented case of the illness in the United States.
Plague is a rare, lethal, and flea-borne disease caused by the bacterium Yersinia pestis. A plague is passed from one wild rodent to another through their fleas. Human transmission happens when a human is bitten by an infected flea, inhaled contaminated droplets from infected animals or persons and had direct contact with tainted tissues or body fluids, such as those of ill domesticated pets like dogs and cats. It can take two to six days since the exposure for the bacterium to incubate and cause illness.
Common symptoms of plague infection among humans include fever supplemented by vomiting, nausea and abdominal pain. There are three main types of plague caused by the bacterium Yersinia pestis. The type of plague is dependent on the infection's route in the human body.
Bubonic plague, which makes up 80 to 85 percent of the plague cases, stems from a flea bite where patients can develop a painful swelling of lymph nodes. These swollen lymph nodes are called 'bubo' which intensify during the onset of the illness.
The second type is called Septicemic plague that makes up 10 percent of the overall cases. Here, the infection is caught through flea bites or direct contact with infected fluids. The bacterium propagates directly in the bloodstream with no localizing signs.
The third type is called primary pneumonic plague, which accounts for 3 percent of plague cases. Here, the disease is caught from exposure to contaminated droplets in the air. A more progressive type is called the secondary pneumonic plague wherein the bacterium has spread to the human lungs of patients whose septicemic and bubonic infection were left untreated.
During the pre-antibiotic days, mortality rate ranged between 66 to 93 percent. Today, treatments using antimicrobials has decreased the mortality rate to nearly 16 percent.
In the U.S., the first plague is believed to have originated from rat-infested steamships that docked in the 1900. The last known plague epidemic in the U.S. was in 1920s in Los Angeles. Several cases pop up occasionally but mostly contained in the Western and Southwestern rural areas pestered with a wild rodent population.
The documented cases of bubonic plague in the U.S. have seen a steady increase since 2010, when two people were diagnosed with the illness. In 2015, three people died from the disease.
"It is unclear why the number of cases in 2015 is higher than usual." according to the Morbidity and Mortality Weekly Report (MMWR) published by the Centers for Disease Control and Prevention in August 2015.
"Many people think of the plague as a disease of the past, but it's still very much present in our environment, particularly among wildlife. Fortunately, plague remains a rare disease, but people need to take appropriate precautions with wildlife and their pets to keep it that way," said Emilio DeBess, Oregon's public health veterinarian.
Photo:National Institute of Allergy and Infectious Disease (NIAID) | Flickr
