Le diagnostic de la peste

Plague is a bacterial disease caused by a small Gram negative bacterium: Yersinia pestis. Far from having disappeared, the disease continues to cause epidemics and is currently re-emerging in countries where no human cases had been recorded for decades. Rodents are the main reservoir for plague and the disease is transmitted from rodent to rodent by the bite of fleas. Human infection has two main clinical forms: bubonic plague and pneumonic plague. The first results from a bite by an infected flea while the second is secondary to inhalation of infected aerosols. In the absence of appropriate and early treatment, mortality occurs in usually less than a week in 40-70% of human cases with bubonic plague and is almost systematically fatal during pneumonic plague. The clinical diagnosis of plague is not always easy, especially when disease occurs in a non-endemic area. Confirmatory diagnosis is based on isolation of the bacillus, but takes several days. Dipstick tests are now available and allow a rapid and efficient diagnosis of the disease although bacteriological confirmation is still required for index cases. The plague bacillus is generally susceptible to antibiotics despite the recent isolation of antibiotic-resistant strains. Since the chances of patient survival are directly related to the earliness of the establishment of an efficient antibiotic therapy, it is essential that the diagnosis be carried as quickly as possible.