The recent outbreak of plague in Madagascar has raised the spectre of ancient diseases, with history books full of episodes where this disease wiped out millions of people in the centuries before antibiotics. 25 million was the estimate for the first pandemic in around 541 AD. The Black Death (the second pandemic) originated in China in 1334 and spread along the great trade routes ultimately to Europe where 60% of the population were decimated. Indeed in the Middle Ages, the legend of the Pied Piper of Hamlin may have evolved out of the need to rid towns of the all too common infestation of rats. The most modern plague epidemic also began in China, in the 1860s and spread via rats on ships to the ports of the world, killing approximately 10 million people. Only then did medical science, specifically a Swiss-French physician Alexandre Yersin, finally identify the causative agent as a bacterium – ultimately named Yersinia Pestis. Bacteria – the germs that cause all manner of disease from tonsillitis to urinary tract infections – and are usually effectively treated with antibiotics (unlike viruses and other infectious agents). And in the case of plague thankfully, a relatively cheap and easily available antibiotic in the tetracycline family still works.

So what is plague and how do people get it ? Plague is found in many areas of the world (from Madagascar to Peru) and the bacterium mainly affects rodents. It is occasionally transmitted to humans when they are bitten by fleas carrying the bacteria, or more rarely via contact with an infected animal or person. There are three main forms of plague in humans – bubonic, septicaemic and pneumonic. The bubonic form of plague is more common and occurs as the result of a bite from an infected flea that has been living on an infected small animal. The plague bacteria travel through the lymphatic system to the nearest lymph node (or “gland”). That lymph node becomes massively enlarged and tender, forming a “bubo”. Without antibiotics, the fatality rate is about 50%! The septicaemic form of plague occurs when the infection spreads in the bloodstream. Without early antibiotic treatment, this form of plague is usually fatal, even with subsequent treatment. The pneumonic form of plague occurs when Y. pestis infects the lungs. The first signs of pneumonic plague are fever, headache, weakness and cough that produces bloody or watery sputum. The pneumonia progresses over two to four days and may cause septic shock and, without early treatment, death. This form of plague can unfortunately move from person to person. The sick person coughs infectious respiratory droplets into the air which can spread the bacteria to others. Without early treatment the fatality rate is staggeringly near 100%. People who have had face-to-face contact with a pneumonic plague patient should be given prophylactic antibiotics which are very effective. There is no viable vaccine for plague – so in order to combat it, the symptoms have to be recognised and the patient provided with appropriate treatment. Wow – so essentially if you get plague and you don’t get early antibiotic treatment – you could very well die!

In Madagascar recently, the challenge and the reason for the high case load has been the unusual predominance of pneumonic plague. A few hundred cases of bubonic plague have always occurred seasonally, but this respiratory form has taken hold of the resource and public health challenged major cities and killed almost 100 people (out of 1300 cases in late October 2017). As a traveller, should you have to go to Mada’ – your safety strategy should include avoiding crowded areas such as markets and public transport, avoiding sick patients, observing strict personal hygiene measures, avoiding sick or dead animals, avoiding rodent nests or burrows and taking steps to avoid flea bites. When outdoors, wear clothing that covers most of your body (long sleeves, long pants, socks). And use an effective insect repellent, such as one containing DEET, Picaridin, PMD or IR3535.

That should do the trick.