Yersinia pestis

black death

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This bacteria is bacilli shaped and is a rod-shaped facultative anaerobe with bipolar staining

How it attacks and spreads

Bacteria are typically transmitted to and among rodents via flea bite. Humans may contract plague through a flea bite or by handling an infected animal or breathing in an aerosolized form of the bacteria.

Who and where it strikes

It can generally been found only in developing countries.Poor housing and sanitation conditions tend to find more outbreaks, as well as amount rural communities or in cities. Infected rats are usually to blame.


1st stage The pneumonic plague results in fever, cough, chest pain, lethargy, chills, dyspnea (breathlessness), hemoptysis (coughing up of blood), hypotension (abnormally low blood pressure), and shock.
2nd stage The bubonic plague is actively attacking bacteria, after an incubation period of 2-6 days. The victim will suffer from buboes, particularly regarding the inguinal nodes, headache, fever, and a lack of energy.
3rd stage The septicemic plague results in hypotension, hepatosphlenomegaly (enlargement of the liver and spleen) delirium, seizures (in children), shock, lack of energy and fever

Many of the cases are rare and severe.


There are about 2500 cases a year and 1000 will die.

Weapons against the bacteria

Cleanliness and Early antibiotic therapy is recommended for persons deemed exposed to or infected with plague. Tetracyclines (eg, doxycycline), fluoroquinolones (eg, ciprofloxacin), and aminoglycosides (eg, streptomycin, although not widely available, and gentamicin) are all antibiotics that have been used for post-exposure prophylaxis and treatment of plague.