Black death
Plague.
- Plague is an infectious disease that affects rodents, certain other animals and humans. It is caused by the Yersinia pestis bacteria. These bacteria are found in many areas of the world, including the United States.
- People most commonly acquire plague when they are bitten by a flea that is infected with the plague bacteria. People can also become infected from direct contact with infected tissues or fluids while handling an animal that is sick with or that has died from plague. Finally, people can become infected from inhaling respiratory droplets after close contact with cats and humans with pneumonic plague.
The different forms of plague
- Bubonic plague
- Patients develop sudden onset of fever, headache, chills, and weakness and one or more swollen, tender and painful lymph nodes (called buboes). This form is usually the result of an infected flea bite. The bacteria multiply in the lymph node closest to where the bacteria entered the human body. If the patient is not treated with appropriate antibiotics, the bacteria can spread to other parts of the body.
- Septicemic plague
- Patients develop fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. Skin and other tissues may turn black and die, especially on fingers, toes, and the nose. Septicemic plague can occur as the first symptoms of plague, or may develop from untreated bubonic plague. This form results from bites of infected fleas or from handling an infected animal.
- Pneumonic plague
- Patients develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery mucous. Pneumonic plague may develop from inhaling infectious droplets or from untreated bubonic or septicemic plague that spreads to the lungs. The pneumonia may cause respiratory failure and shock. Pneumonic plague is the most serious form of the disease and is the only form of plague that can be spread from person to person (by infectious droplets).
* Type of plague
Basic transmission cycle of plague.
- Fleas become infected by feeding on rodents, such as chipmunks, prairie dogs, ground squirrels, mice, and other mammals that are infected with the bacterium Yersinia pestis. Fleas transmit the plague bacteria to humans and other mammals during a subsequent feeding. The plague bacteria survive briefly (a few days) in the blood of rodents and for longer periods in the fleas.
Could one person get plague from another person?
Yes, when a person has plague pneumonia they may cough droplets containing the plague bacteria into air. If these bacteria-containing droplets are breathed in by another person they can cause pneumonic plague. Human-to-human transmission is rare and typically requires direct and close contact with the person with pneumonic plague.
- Pneumonic plague symptoms may appear as quickly as one day after exposure to the bacteria and include:
- trouble breathing.
- chest pain.
- cough.
- fever.
- headache.
- overall weakness.
- bloody sputum (saliva and mucus or pus from the lungs)
Causes of plague
Incubation Period
- A person usually becomes ill with bubonic plague 2 to 6 days after being infected. Someone exposed toYersinia pestis through the air would become ill within 1 to 3 days.
- When bubonic plague is left untreated, plague bacteria can invade the bloodstream. When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition called septicemic plague. Untreated bubonic plague can also progress into an infection of the lungs, causing pneumonic plague. If plague patients are not given specific antibiotic therapy, all forms of plague can progress rapidly to death.
Prevention and Control
How can you keep from Getting Plague?
Treatment
To lower your risk of getting plague from a natural source:
- Do not handle sick or dead animal bodies. But if you must, then use gloves plus face and eye protection.
- Avoid rodents (mice, rats) and rodent droppings.
- Avoid insect bites by using an insect repellent containing DEET.
- Eliminate fleas from your home.
- Avoid touching infected tissues, materials, or body fluids from a plague-infected person or animal.
- Keep a minimum of 3 feet between you and anyone who may have the lung form of plague (pneumonia).
- It is always a good idea to wash your hands regularly and avoid touching your eyes, nose, and mouth.
If terrorists release plague bacteria on purpose, check for recommendations from SFDPH.
Precautions
- All patients with suspected plague and signs of pneumonia should be placed in strict respiratory isolation for 48-72 hours after antibiotic therapy is initiated and kept there until pneumonia has been ruled out or until sputum culture have shown negative findings.
- Report patients thought to have plague to the local health department and to the WHO.
- Alert laboratory personnel to the possibility of the diagnosis of plague. All fluid specimens must be handled with gloves and mask to prevent aerosolization of the infected fluids.
Supportive therapy
- Hemodynamic monitoring and ventilatory support are performed as appropriate.
- Intravenous fluids, epinephrine, and dopamine are implemented as necessary for correction of dehydration and hypotension.
Postexposure prophylaxis
- Presumptive therapy consists of a 7-day course of oral doxycycline and ciprofloxacin. Chloramphenicol may be used as an alternative. Levofloxacin may be prescribed as a 10-14 day regimen for either treatment or postexposure prophylaxis.
- In a community experiencing a pneumonic plague epidemic, individuals with a temperature of 38.5°C or higher or newly onset cough should promptly receive parenteral antimicrobial therapy.
Vaccine Recipients
Vaccination is recommended for:
- All laboratory and field personnel who are working with Y. pestis organisms resistant to antimicrobics,
- Persons engaged in aerosol experiments with Y. pestis
- Persons engaged in field operations in areas with enzootic plague where preventing exposure is not possible (such as some disaster areas).
- Laboratory personnel regularly working with Y. pestis or plague-infected rodents,
3. Persons whose vocation brings them into regular contact with wild rodents or rabbits in areas with enzootic plague.
Primary Vaccination
All injections should be given intramuscularly.
Adults and children greater than or equal to 11 years old: The primary series consists of 3 doses of vaccine. The first dose, 1.0 ml, is followed by the second dose, 0.2 ml, 4 weeks later. The third dose, 0.2 ml, is administered 6 months after the first dose. If an accelerated schedule is essential, 3 doses of 0.5 ml each, administered at least 1 week apart, may be given. The efficacy of this schedule has not been determined.
Children less than or equal to 10 years old: The primary series is also 3 doses of vaccine, but the doses are smaller. The intervals between injections are the same as for adults.
Booster Doses
When needed because of continuing exposure, 3 booster doses should be given at approximately 6-month intervals. Thereafter, antibody levels decline slowly and booster doses at 1- to 2-year intervals, depending on the degree of continuing exposure, should provide good protection.
The recommended booster dosages for children and adults are the same as the second and third doses in the primary series. However, if serious side effects to the vaccine occur, their severity may be reduced by using half the usual dose. The primary series need never be repeated for booster doses to be effective
“oriental rat flea,” one of the major vectors for transmission of the bacterium Yersinia pestis, the causative agent of plague.
Microscopic view of plague
bacteria
Men gets the plague from his cat
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