The Plague: Rare But Not Forgotten in the Public Health World
When you hear the word plague, it might call to mind images from centuries ago. However, this week the public health world was reminded the past is never quite behind us when a 16-year-old Colorado boy died from a rare strain of septicemic plague. Thought to have been contracted from bites from infected fleas, septicemic plague is a rare form of the plague where the bacteria directly enters the bloodstream. Typically, transmission of any form of the plague occurs when fleas that live on infected rodents such as rats, squirrels, and prairie dogs, bite humans. Because plague symptoms often look similar to the flu—swollen lymph nodes, fever, chills, and headaches—it can be difficult to diagnose.
Although the Colorado teen’s septicemic case is rare—only 3 cases are known in the last 30 years—plague cases, while not exactly common, are not unheard of, especially in the U.S west. The CDC reports an average of 7 cases in the U.S. a year, with almost all cases occurring in New Mexico, Arizona, Colorado, and California. Last summer (2014), for example, there was a cluster of plague cases in Colorado surrounding contact with an infected dog. There, happily, all four patients recovered, even though the first patient was initially misdiagnosed with a different bacterial infection. Back in 2013, a 15-year old in New Mexico was diagnosed with the plague and was stabilized, but health officials were unclear on how he contracted the bacteria.
The good news is, the mortality rate from plague is very low when properly and timely diagnosed, as modern antibiotics make it quite treatable. However, the CDC cites clusters of cases as reinforcing the need to routinely consider plague diagnostically for animals in areas where plague is typically found. Doing so may help diagnose humans quicker, as well as help contain the spread among infected animals. For example, in 2013, Los Angeles County Officials temporarily closed parts of the Angeles National Forest after they discovered that a trapped ground squirrel tested positive for the plague. This year in New Mexico, the state Department of Health has confirmed four cases of the plague in a dog, rabbit, mouse, and a cat. Though still rare, such animal cases, as well as the tragic case of the Colorado teen, are reminders that this disease remains a concern for public health officials in the western U.S.