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Yersina pestis
- 1. YERSINIA PESTIS SUBMITTED TO:MRS. REENA THAKUR SUBMITTED BY: MUSKAAN SHARMA SUBJECT: MEDICAL MICROBIOLOGY BSC (HONS) BIOTECHNOLOGY 3RD YEAR
- 2. Yersinia Pestis YersiniaPestis is a gram negative and noncapsulated, facultative anaerobic microorganism Yersinia pestis was discovered in 1894 by Alexandre yersin Yersinia pestis, the cause of bubonic and pneumonic plague in humans, persists in populations of wild rodents in many parts of the world and is transmitted primarily by the bites of infected fleas Plague caused by Yersinia pestis is categorized as a rare disease. The disease rarely occurs but when it strikes, the consequences can be devastating
- 3. Y. Pestisis usually transmitted by the bite of an infected flea or inhalation of aerosolized droplets from a person with pneumonic plague Infection by the bacterium Yersinia pestis is most often associated with the infamous Black Death of the middle Ages, a pandemic that cost Europe a third of its population in the 14th and 15th centuries
- 5. Epidemiology The plagueare grouped into three plague pandemics In the 6th century In the 14th century known as the black death which killed up to an estimated 17 to 28 million people At the end of 19th century following the spread of infection from china Plague is a seasonal disease, with most reported human cases occurring between March and October
- 6. 1000- 3000 cases reportedannually across the world Africa , Asia Northeastern Brazil · Andes Mountain Regions US (19-40 cases a year mostly in Western areas such as New Mexico and Arizona) About 15% of reported humans with plague die
- 7. Types Of Plague Bubonic plague is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. Pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself. The lymph node then becomes inflamed, tense and painful, and is called a ‘bubo’. At advanced stages of the infection the inflamed lymph nodes can turn into open sores filled with pus. Human to human transmission of bubonic plague is rare.
- 8. Pneumonic plague, orlung-based plague, is the most virulent form of plague. It is the more severe type of plague called pneumonic plague Incubation can be as short as 24 hours. Any with pneumonic plague may transmit the disease droplets to other humans. Untreated pneumonic plague, if not diagnosed and treated early, can be dangerous. However, recovery rates are high if detected and treated in time
- 9. Pathogenesis And Life Cycle Yersinia pestis is primarily a rodent pathogen, with humans being an accidental host when bitten by an infected rat flea. The flea draws viable Y. Pestis organisms into its intestinal tract. These organisms multiply in the flea and block the flea’s proventriculus. Thus, the flea repeatedly attempts to feed, and because it is unable to ingest the blood, it regurgitates the newly infected blood back into the bloodstream of the mammal on which it is feeding, therefore transferring the microorganism from the flea to the mammal.
- 10. Approximately 25,000to 100,000 Y. Pestis organisms are inoculated into the skin of the mammal host during this process. The bacteria migrate through cutaneous lymphatics to regional lymph nodes where they are phagocytosed but resist destruction They rapidly multiply, causing destruction and necrosis of lymph node architecture with subsequent bacteremia, septicemia, and endotoxemia that can lead quickly to shock, disseminated intravascular coagulation, and coma
- 12. Symptoms Patients typicallydevelop symptoms of bubonic plague 2 to 8 days after being bitten by an infected flear Bubonic plague incubation period of 2-6 days, when the bacteria is actively replicating. Fever Headache and chills occur suddenly at the end of the incubation period Swelling of lymph nodes resulting in buboes, the classic sign of bubonic plague Death Cain accur in less than 2 weeks
- 13. Pneumonic plague (Spreadperson to person) Fever Chills Coughing Chest pain Dyspnea Hemoptysis Lethargy Hypotension Shock 100% mortality if not treated
- 14. Labortory Diagnosis Yersiniapestis can be identified in the laboratory by both bacteriologic and serologic methods Diagnosis can be made from a variety of samples, including blood, aspirates from involved lymph nodes, skin scrapings, cerebrospinal fluid, urine, and sputum Yersinia pestis appears as a pleomorphic gram negative rod and may appear as a single cell or in short chains in smears
- 15. Treatment If diagnosedin time ,the various forms of plague are usually highly responsive to antibiotic therapy The antibiotics often used are Streptomycin, Chloramphenicol and Tetracycline The newer generation of antibiotics are Gentamicin and Doxycycline have proven to use against this bacteria
- 16. Vaccination In anew study, researchers tested three vaccines that were designed to protect people against infection from the bacteria that cause plague , to create this vaccine researchers modified several genes of bacteria so that they couldn’t cause disease. Specifically the vaccines were designed to protect people against pneumonic plague.
- 17. Preventions Animal control: Avoid sick and dead animals Killed vaccines are available for high risk occupation controlling the spread of ratsin urban areas,