Yersinia pestis, a pathogen that resists oblivion

Abstract

Plague, a zoonotic infection caused by Yersinia pestis, has not been detected in Europe for over fifty years, but it continues to show a significant presence in the world and especially in some countries of the Americas, Africa and Asia. This bacterium is classified as a Tier 1 bioterrorism agent and it consequently poses a great threat to public health and safety. Its main reservoir is formed by small rodents and the disease is transmitted via fleas, mainly including the Oriental rat flea (Xenopsylla cheopis), although it may also be transmitted by such ectoparasites as lice. Moreover, humans may acquire the disease by direct contact with infected fluids or tissues, by inhalation of drops transmitted by the coughing of infected humans or house cats, or by the maternal-foetal route. The disease has three main clinical forms: bubonic, pneumonic (primary, or secondary to bubonic) and septicemic plague. Although diagnosis must be made in laboratories with a high level of safety, there are now several forms of rapid diagnosis through techniques such as immunochromatography or PCR, which shorten the required time in comparison to culture and allow decisions to be made close to the patient. Antimicrobial treatment with tetracyclines, fluoroquinolones or aminoglycosides must be administered early in order to prevent the disease from progressing to severity and the patient’s death. No effective vaccine exists and active prevention and surveillance must be carried out by a one health approach, taking into account at one time the human being and the animal and environmental reservoirs.