When the plague is mentioned, I get flashbacks of history classes at school; mainly men in scary beak suits, “The Great Plague” and stray chamber pots contributing to disease spread. The reality in fact, is that the plague is still alive and kicking today. In 2015, the USA had 16 new cases of the plague confirmed by the CDC; the highest number of cases this century. Surprisingly, new cases are not unusual.
There are three types of plague, caused by the Yersinia pestis bacteria; bubonic, pneumonic and septicemic. The bubonic plague is spread mainly by ticks infected by the bacteria. With the bubonic type, patients may experience distinctive lumps, also called buboes, at lymphatic sites such as the groin. Bubonic plague is the least severe of the three types; patients can usually be successfully treated by antibiotics. Alternatively, the pneumonic type attacks the lungs of victims; making it the most severe of the three. This type of plague is airborne, transmitted by coughing and therefore spreads rapidly. With the highest fatality rates, patients can die within 24 hours if untreated. Scary right? When Y. pestis has the opportunity to enter a patient’s bloodstream, the infection can become septicemic, which is often lethal.
Unfortunately, experts believe that the people of London in the Middle Ages (1346-53) were hit by a combination of both bubonic and pneumonic plague. This pandemic was famously known as The Black Death. The extreme poverty and living conditions at the time meant that spread of the disease was inevitable. The Black Death wiped out around a third of the population in London during the course of the infection. Eventually, low temperatures of winter were thought to kill off fleas and slow disease spread. Interestingly however, since the great outbreaks, the plague has never been completely eradicated.
If you’re still up for reading this article, the bad news continues. Whilst infection is not quite on the same scale as the middle ages, Yersinia pestis is still responsible for between 1000 and 3000 cases of plague every year. The disease persists as before in areas with poor hygiene and overcrowding: Asia, Africa and South America in particular. Worryingly, more developed countries such as North America continue to experience plague outbreaks.
The Devilish culprit- A Prairie dog
Why has the USA struggled to eradicate the plague? Modern antibiotics have dramatically reduced plague fatality rates. Over 80% of new plague cases are of the bubonic type, which is easier to treat and recover from. Nearly all of the cases in the USA are restricted to the western side of the country and are more commonly seen in summer, when people spend more time outside. One of the main carriers of plague in North America is the Prairie dog. Prairie dogs are social animals, helping infected ticks spread rapidly; both to other prairie dogs and nearby humans.
An animal reservoir makes a disease much harder to eradicate. In the UK there is a similar problem with persistent tuberculosis cases; leading to the ongoing debate over badger culling or vaccination for disease eradication. Whilst the UK remains undecided on the best course of action, scientists at the National Wildlife Health centre in the USA, are in the process of developing vaccines for prairie dogs; in the hope this will greatly reduce the amount of infections.
Throughout the USA the plague caused 4 fatalities in 2015; the highest number this century. In comparison to monsters like cardiovascular disease and cancers, this number is minuscule. As previously discussed however, a rise in bacterial infections is worrying; particularly when antibiotics are one of the “circumstances” that are repressing the plague. The 2015 plague mortality figure suggests these circumstances are not fool-proof. A rise in fatalities demonstrates treatments are becoming less effective and indicates preventative measures should be introduced. Other studies have also confirmed that certain plague patients have acquired strains with resistance to the normal antibiotics.
Controversially, the lax attitude of the CDC has resulted in persistence of plague cases. Instead of eradicating the disease at the source, the easy option of treating plague patients was taken. It is undeniably time we stopped putting faith in antibiotics. Prevention therefore is arguably better than cure; removing the need to rely upon antibiotics that will one day be ineffective. Vaccines could prevent the carrier stage; decreasing transmission to humans. However, implementation takes time; especially when working with animal carriers who dislike being jabbed with needles.
Vaccines will be hugely beneficial. Once established in the USA it is possible that preventative efforts could be distributed worldwide. Studying the plague highlights the importance of not ignoring the neglected infections; a disease that wiped out 50 million people in the 14th century has not yet lost the ability to do it again. Realistically, the plague is unlikely to make a return whilst we keep eradication firmly in our sights; so don’t worry too much.