Plague is a zoonosis caused by the bacteria Yersinia pestis, which is most often transmitted from rodents to humans by fleas, but also between humans by the respiratory route. Without appropriate and rapid antibiotic treatment, its course is fatal in 30% to 60% of cases (1).

It’s hard to imagine that the “black death” which decimated Europe in the 1920th century is still raging in certain regions of the world! In France, the last cases of plague were recorded in 1945 in Paris and in 50 in Corsica. But globally, more than 000 cases have been reported to WHO in 26 countries since the early 2s (XNUMX).

In recent years, several outbreaks of plague have been recorded by the World Health Organization, in the Democratic Republic of the Congo, Tanzania, China, Peru and Madagascar. The latter is the main endemic country, several dozen people having been killed by the plague in 2014/2015 (3).

Plague presents several clinical forms (septicaemic, hemorrhagic, gastrointestinal, etc., and even mild forms), but two are largely predominant in humans:

The most common bubonic plague. It is declared with the sudden onset of high fever, headaches, a profound attack of the general condition and disturbances of consciousness. It is characterized by swelling of the lymph nodes, often in the neck, armpits and groin (buboes).

The pulmonary plague, the deadliest. A mucopurulent cough with blood and chest pain are added to the general symptoms of bubonic plague.

The agent of plague is a Gram-negative bacillus, Yersinia pestis. Yersinia are a genus of bacteria belonging to the Enterobacteriaceae family, which includes seventeen species, three of which are pathogenic for humans: pestis, enterocolitica et pseudotuberculosis. Rodents are the main, but not exclusive, reservoir of the disease.

Plague infects small animals and the fleas that parasitize them. It is transmitted from animals to humans by bites from infected fleas, by direct contact, by inhalation and by ingestion of infectious substances.

• Humans bitten by an infected flea usually develop the bubonic form.
• If the bacillus Yersinia pestis reaches the lungs, the individual develops pulmonary plague which can then be transmitted to other people by the respiratory route during coughing.

In endemic areas, guard against flea bites and keep away from rodents and animal carcasses.

If diagnosed in time, bubonic plague can be treated successfully with antibiotics: streptomycin, chloramphenicol and tetracyclines are the reference antibiotics recommended by the Institut Pasteur.

Chemoprophylaxis (also called “chemoprevention”), which consists of administering tetracyclines or sulfonamides, in the case of plague, is effective in protecting the immediate surroundings of affected subjects, also explains the Institut Pasteur.

Several vaccines have been developed in the past, but they are now reserved for laboratory personnel, because they have proved to be ineffective in controlling epidemics.