Life cycle treatment

1. YERSINIA PESTIS
SUBMITTED TO: MRS. REENA THAKUR SUBMITTED BY: MUSKAAN SHARMA
SUBJECT: MEDICAL MICROBIOLOGY BSC (HONS) BIOTECHNOLOGY 3RD
YEAR

2. Yersinia Pestis
 Yersinia Pestis 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. Pestis is 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 plague are 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
reported annually
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, or lung-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 25,000 to 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 typically develop 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 (Spread person to person)
 Fever
 Chills
 Coughing
 Chest pain
 Dyspnea
 Hemoptysis
 Lethargy
 Hypotension Shock
 100% mortality if not treated

14. Labortory Diagnosis
 Yersinia pestis 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 diagnosed in 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 a new 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,