YERSINIA PESTIS AND FRANCISELLA TULARENSIS: PATHOGENESIS, LABORATORY DIAGNOSIS, SPECIFIC PREVENTION, AND THERAPY

Yersinia pestis and Francisella tularensis are highly pathogenic Gram-negative bacteria responsible for severe zoonotic diseases in humans. Both organisms are considered important public health threats due to their high virulence, low infectious dose, and ability to spread through animal reservoirs and arthropod vectors. Yersinia pestis, the causative agent of plague, is mainly transmitted through infected fleas from rodents. After entering the human body, it rapidly spreads to lymph nodes and blood, leading to bubonic, septicemic, or pneumonic forms of the disease. Pneumonic plague is particularly dangerous due to its ability for human-to-human transmission via respiratory droplets. Francisella tularensis, the agent of tularemia, is transmitted through direct contact with infected animals, tick bites, contaminated food or water, or inhalation of aerosols. It is an intracellular pathogen that survives within macrophages, allowing systemic spread and immune evasion. Both pathogens are characterized by high infectivity and significant mortality if untreated, making them important targets for laboratory surveillance, early diagnosis, and effective therapeutic intervention.