Is this plague the same thing as the bubonic plague that ravaged Europe in the Middle Ages?
Yes, plague is caused by the Yersinia Pestis bacteria. Bubonic plague just means this bacteria is growing in the lymph nodes (what people used to call the boboes) and is the least severe form of the disease. This patient had pneumonic plague which means he had Yersinia Pestis in his lungs. It is this form of Yersinia which is most troubling because the coughing that results can spread the disease through the air and infect others. They believe that three other people were infected by this man in this way. The patients all survived once placed on antibiotics but the dog went on to develop septicemic plague where the bacteria made it into the bloodstream and resulted in severe bleeding.
Is this a serious outbreak, should people be worried?
Over 97% of all cases of plague occur in Africa and it is rats and fleas that are the main ways it is spread. There are about 1,800 cases in Congo and Madagascar alone. In the Western United States, prairie dogs and squirrels are the primary rodents infected. In the United States about 8 people a year get bubonic plague by being bitten by a flea or a rodent. The people then develop sore swollen glands, fever, headache, chills, and generalized weakness. People usually seek medical help and receive antibiotics to prevent it from moving to the blood and/or the lungs. There have been other cases of dog to human transmission followed by human to human transmission in China in 2009.
While this is concerning, these infections have almost always occurred in the Western United States and cases have not yet been reported here. Since it is highly responsive to antibiotics and we have much better disease transmission and quarantine protocols, the chance of it spiraling out of control is low if it is detected early enough. One of the issues in this case was that the initial laboratory tests for pneumonia did not include Yersinia and it was only after several more days that this was discovered. That suggests our healthcare system is not prepared to rapidly identify it and others might be exposed as a result. So it isn’t time to hide in the bomb shelter but doctors, veterinarians, and public health professionals need to be more vigilant and aware.
What about a plague found in the NYC subway system?
In February, it was reported that samples taken from the subway system in NYC were analyzed and the genetic code for Yersinia Pestis was found in the analysis. The levels were said to be extremely low and not a factor in human health. However, it does remind us that while dormant here in the Eastern United States it is still around and if a strain arises or arrives from elsewhere in the world that is more virulent, rats can be infected and transmit that disease through fleas or directly through rat bites to people.
Dr. Michael White, Department of Pharmacy Practice, UConn School of Pharmacy