- The first known plague pandemic began in Egypt 541 AD
and spread to other parts of the world during the following four years.
About 50 to 60% of the world population is estimated to have died from
the plague.
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- In 1345 to 1350, the second plague pandemic swept over
the world. The disease, also known as the Black Death, erupted about 25
years earlier in central Asia, probably in what is today Mongolia. Following
trade routes and human movements the plague moved through China, Russia,
the Middle East, the Mediterranean and Europe. It lasted around 130 years,
killing more than 13 million in China alone, and about 20 to 30 million
in Europe ÷ a third of Europe's total population at the time.
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- The Great Plague of London killed nearly one out of every
six citizens of London during the years 1664-65.
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- The third pandemic erupted in China 1855, and led to
more than 12 million deaths in China and India alone. It spread around
the globe, and reached San Francisco's Chinatown in the year 1900 During
the following four years it infected 121 people, with 118 deaths. A secondary
plague epidemic occurred in San Francisco 1907, with 160 cases and 77 deaths.
This outbreak was probably linked both to plague rats surviving the anti-rat
campaign of 1904, and disruptions that followed the 1906 earthquake.
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- As a result of the outbreaks in San Francisco 1900 to
1907, plague is now established permanently in the western and southwestern
United States. Infected plague rats have wandered into the forests and
exchanged fleas with wild rats, squirrels and prairie dogs that now carry
living cultures of dormant plague germs.
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- The last sizable plague outbreak in the U.S. took place
in Los Angeles in 1924-25. Forty people were infected; only two survived.
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- Between 1947 and 1996 there were 390 cases of plague
reported in the United States, with most cases in New Mexico, Arizona,
Colorado, and California.
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- India experienced an outbreak of pneumonic plague in
1994. It occurred in the industrial city of Surat, about 200 miles north
of Bombay. The outbreak followed an earthquake where more than ten thousand
people were killed and about a million homes were destroyed. The earthquake
destroyed farmers' grain storage buildings, which created an excess of
food for rats carrying plague fleas. Both the rats and the flies reproduced
quickly, and first infected humans with bubonic plague, which soon developed
into pneumonic plague, transmitted from person to person through droplets
in the air. After rumours started to circulate about tens of thousands
infected with the plague and many deaths, about a half million civilians
and most medical professionals fled the city by bus, train, and car. In
the end, 56 people died, while almost 6,500 were cured with antibiotics.
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- Bubonic plague has survived as an infection of rats and
other rodents, squirrels, and prairie dogs on all continents except Australia.
Worldwide, on average, about 1700 cases are reported each year.
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- The Bacillus and its Natural Reservoir
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- Plague is caused by Yersinia pestis, a gram-negative
bacillus (bacterium). The plague microbe is named after Alexandre Yersin,
a Swiss scientist that started his career in the lab of Louis Pasteur,
and in the late 19th century discovered the bacillus.
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- Plague is an infectious disease with its natural reservoir
in wild rodents. It is transmitted from rodent to rodent by the Xenopsylla
cheopis, a flea whose favorite food is the blood of rodents, with human
blood as a second choice.
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- Sudden excessive rat die-off is often seen as a prologue
to a human plague epidemic. When the fleas are running short of rats live
from, they turn to humans. Most people infected by this route develop bubonic
plague, with a small minority acquiring primary septicemic plague. A small
percentage of those infected with bubonic or septicemic plague also develop
pneumonic plague. (See Transmission, below, for more information on types
of plague infection.)
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- The bite by a plague-infected flea is like getting a
shot of thousands of plague organisms. Those are then transported by the
blood system to regional lymph nodes, where they fast reproduce.
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- The plague flea is quite rugged. It can survive for up
to a year without a rodent host to feed on.
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- The plague bacillus is highly susceptible to effects
of sunlight and heat. It does not survive long in an outdoor environment.
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- Transmission
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- Plague is a zoonotic disease, which means that people
can catch it from animals.
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- It can take three forms, depending on whether the infection
enters the lymph nodes (bubonic), the bloodstream (septicemic) or the lungs
(pneumonic).
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- Bubonic plague is normally transmitted by fleas from
rats and other rodents, squirrels, and prairie dogs. Of human cases in
the U.S. from 1947 to 1996, fifteen were transmitted from domestic cats
infected with plague.
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- A small number of patients infected by fleas develop
primary septicemic plague. Secondary septicemic plague can arise from bubonic
plague.
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- Secondary pneumonic plague develops in a minority of
patients with bubonic or primary septicemic plague. Primary pneumonic plague
is caused by direct inhalation of plague bacillus. Pneumonic plague is
highly infectious and can be transmitted by respiratory droplets from animals
to humans, or humans to humans.
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- In Madagascar in 1997, a patient with bubonic plague
developed secondary pneumonic plague, which was transmitted to 18 people,
with 8 deaths.
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- Laboratory work with the plague bacillus requires Biosafety
Level 2 conditions, with BL-3 precautions when performing activities involving
high risk for aerosol or droplet production.
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- Diagnosis and Detection
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- Few U.S. physicians have ever diagnosed a case of pneumonic
plague. Early symptoms could easily be mistaken for acute flu-like illness.
-
- Rapid diagnostic tests for plague are not currently available.
Only some state laboratories, CDC and the military can confirm a suspected
diagnosis. Routinely used antibody tests can not be used for early diagnosis,
because it takes several days to weeks before antibodies develop in a plague
patient.
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- The Association of Public Health Laboratories and the
CDC are together developing new standards and training for lab diagnosis
of plague.
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- New environmental warning systems that can detect a plague
aerosol are under development.
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- Incubation Period
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- A bubonic plague infection from fleabites generally takes
2 to 8 days before symptoms develop.
-
- Septicemic plague has an incubation period of 1 to 7
days.
-
- The incubation period for pneumonic plague, from exposure
to an aerosol of plague, is most often 2 to 4 days.
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- Clinical Manifestations
-
- Bubonic plague is characterized by fever, headache, chills
and swollen lymph nodes, or "buboes", which ooze pus and blood.
The bubo can reach the size of an orange and is extremely painful. Nausea,
vomiting and diarrhea are also common symptoms. The hemorrhaging causes
cell necrosis and intoxication of the nervous system, which leads to shock
or coma.
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- Septicemic plague patients develop a rash, fever, headache,
chills, weakness and gastrointestinal disturbances. The disease progresses
rapidly, and death can occur within a day of onset of symptoms.
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- Patients with pneumonic plague get high fever, headache,
weakness, muscle pains, and pneumonia with a cough that produces watery
sputum, and later bloody sputum. The lungs are rapidly destroyed, and the
body can't transport enough oxygen, so hands and feet start to turn black.
Pneumonic plague can rapidly progress to respiratory failure.
-
- Of U.S. cases of plague from 1947-1996, about 84% were
bubonic, 13% septicemic, and 2% pneumonic.
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- Mortality
-
- While bubonic plague was responsible for most of the
plague deaths in the Middle Ages, both septicemic and pneumonic plague
are more deadly.
-
- As many as 30 to 50 percent of people with bubonic plague
may survive, even without treatment.
-
- Untreated septicemic plague is always fatal.
-
- The fatality rate of patients with pneumonic plague ÷
without treatment, or if not begun within 24 hours of onset of symptoms
÷ is extremely high, or 95% to 100%. The survival rate depends on
the dose of plague inhaled, access to advanced supportive care, and the
time when antibiotic treatment started. The time from a respiratory exposure
of plague to death is normally 2 to 6 days without treatment.
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- Vaccination
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- Dead or inactivated bacteria have been used in plague
vaccines since 1896.
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- A plague vaccine, protecting against bubonic plague,
was previously licensed and used in the U.S. The whole cell bacterial vaccine,
inactivated with formaldehyde and preserved in phenol, was primarily used
by at-risk laboratory personnel and people who travel to plague-infected
areas. The vaccine was discontinued by its manufacturers in 1999 and is
no longer available.
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- Scientists at Porton Down, the British government biological
warfare research center, have used genetic engineering to develop a new
plague vaccine. The vaccine, currently being tested on human volunteers,
uses two harmless proteins used by the plague bacillus to trigger an immune
response against the disease.
-
- Researchers at U.S. Army Medical Research Institute of
Infectious Diseases (USAMRIID) have developed a new vaccine that works
against pneumonic plague in animal experiments. Further tests are underway.
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- Treatment
-
- In a mass casualty emergency, such as a bioterrorism
attack with pneumonic plague, it will not be possible to offer the kind
of hospital treatment advised for a modest number of patients with pneumonic
plague. Mass distribution of antibiotics, temporary emergency treatment
facilities (with only basic care) and homecare (under supervision by family
members) would replace intravenous administration of antibiotics and supportive
care at a modern hospital in most cases, during such a crisis.
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- The Johns Hopkins Working Group on Civilian Biodefense
recommends that if a pneumonic plague outbreak occurs, all people in the
area who develop a temperature of 101.3 degrees Fahrenheit (38.5 degrees
Celcius) or higher, or a new cough, should immediately begin antibiotic
treatment. People without symptoms that have been in close contact, less
than 6.5 feet from contagious pneumonic plague cases, should undergo antibiotic
treatment for 7 days, as a preventive step.
-
- Tetracycline, doxycycline, sulfonamides, and chloramphenicol
are antibiotics that have been used successfully or endorsed against plague
by experts. Fluoroquinolones also worked in lab studies on mice.
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- Intravenous administration of streptomycin is the preferred
choice for a contained outbreak of pneumonic plague. Oral therapy with
doxycycline is recommended by as the first choice treatment for mass casualty
settings.
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- In 1995, the first strain of multidrug-resistant plague
was discovered in a 15-year-old boy in Madagascar. The strain was resistant
to all known antibiotics that work on plague, except trimethoprim.
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- Containment
-
- Today, it's possible to contain an outbreak of bubonic
plague with antibiotics, surveillance of infected victims, and an aggressive
rat-extermination program.
-
- Pneumonic plague, which is airborne, could lead to secondary
spread of cases. The following measures are advised: quarantine of those
infected, surveillance of close contacts, and prescription of antibiotics
in all suspected and confirmed cases. Temporary travel restrictions might
occur.
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- Infection Control
-
- U.S. infection control guidelines for pneumonic plague
recommends the use of disposable surgical masks to prevent person-to-person
transmission via respiratory droplets.
-
- Hospital rooms should get terminal cleaning, with standard
precautions. Bedding and clothing of plague patients, contaminated with
body fluids, should be disinfected.
-
- Laboratory work with the plague bacillus requires Biosafety
Level 2 conditions, with BL-3 precautions when performing activities involving
high risk for aerosol or droplet production.
-
- Contact with remains of plague victims should be limited
to trained personnel, and handled with routine strict precautions.
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- Environmental Decontamination
-
- A WHO study from 1970 estimated that a plague aerosol
would stay infectious for only as long as one hour after an outdoor release.
An indoor release of pneumonic plague could possibly stay infectious for
a longer period, if protected from sunlight and heat.
-
- The Johns Hopkins Working Group on Civilian Biodefense
has concluded that there's no need for environmental decontamination of
an area exposed to a plague aerosol.
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- Plague as a Biological Weapon
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- The Mongols practiced one of the earliest examples of
biological warfare in 1346. During the siege of Kaffa, a coastal town in
the Black Sea, the Mongols, also known as the Tartars, catapulted the remains
of plague victims from their own army into the city. The goal was to start
an epidemic among the defending Genoese, and the attempt was successful.
When the Genoese evacuated Kaffa and returned to Italy, they may have brought
the plague with them, possibly starting the Black Death in Europe.
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- The Japanese biological warfare program conducted research
in occupied Manchuria between 1932 and 1945. About 3,000 scientists worked
with to weaponize plague, anthrax, and other disease agents. The program
used prisoners for terminal experiments in which they studies how to effectively
infect people with plague from fleas. Pathologists conducted autopsies
on some plague victims, while they were still alive, and without anesthetic.
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- The biowarfare program operated a plague flea factory
with 4,500 flea-breeding machines, producing about 100 million plague-infected
fleas every few days. Unit 731, a secret branch of the Japanese army, dropped
plague fleas over populated areas of China. About 15 million fleas were
released per attack.
-
- In June 1944, an assault team of seventeen officers from
Unit 731 sailed for Saipan Island, in the Pacific Ocean, in an attempt
to deny U.S. forces access to the airstrip by dropping porcelain bombs
containing millions of plague-infected fleas. The ship was torpedoed by
a U.S. submarine before it reached its target.
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- During the last frenzied months of World War II, Unit
731 prepared a large biological warfare assault on the U.S. involving special
balloon bombs planned to carry disease across North America. An operation
to use aircraft carried by submarines to drop plague-infected fleas over
southern California was planned for September 1945. But the Japanese Emperor
admitted defeat and surrendered one month prior. The leadership of the
Japanese biowarfare program was after the war granted immunity from war
crimes prosecution on the condition that they disclosed information about
their research.
-
- Nazi Germany built a biological weapons research facility
at Posen, in 1943. Hitler's scientists worked with aircraft spray-tank
dissemination of plague and other germs, but without success.
-
- In the years after World War II, both the United States
and the Soviet Union developed techniques to aerosolize plague, eliminating
the fleas and creating a more deadly and contagious plague weapon.
-
- President Richard Nixon terminated the U.S. offensive
biological weapons program in 1969. The U.S. Army Medical Research Institute
of Infectious Diseases (USAMRIID) was established to proceed with the development
of medical defenses against biological warfare. The United States, Soviet
Union, Iraq and many other countries signed the 1972 Biological Weapons
Convention. Both the Soviets and Iraq secretly continued to develop biological
weapons on a large scale.
-
- The Soviet biowarfare program produced large quantities
of pneumonic plague for bombs and missiles.
-
- In the early 1990s, it was discovered that Iraq had produced
plague in fermenters and freeze-dried the bacteria for use in bombs. Before
the Gulf War, about 1,000 doses of plague vaccine were bought abroad, probably
for the leadership, and researchers and production personnel working with
the plague germ. Western intelligence sources believe that Iraq still maintains
a plague biowarfare program.
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- Plague as a Bioterrorism Agent
-
- An intentional bioterrorism-related outbreak of plague
would most likely occur via an aerosol of the plague bacillus. A plague
aerosol is odorless, colorless, and tasteless. No explosion or cloud would
announce the presence of a lethal disease agent in the air.
-
- A sudden outbreak of pneumonic plague could suggest the
possibility of a bioterrorism attack. The disease would first present itself
as a large number of patients with severe pneumonia and sepsis (blood infection),
and the presence of bacteria or other infectious organisms or their toxins
in the blood or in other tissue.
-
- Few western physicians have ever seen a case of pneumonic
plague, and early symptoms are quite similar to influenza and other diseases,
so the first cases might easily be overlooked.
-
- In May 1995, Larry Wayne Harris, an anti-government "Christian
Patriot" and former member of the Aryan Nation, a neo-Nazi organization,
ordered samples of Yersinia pestis, from the American Type Culture Collection
(ATCC). Mr. Harris, a microbiologist, said he feared an "imminent
invasion from Iraq of super-germ-carrying mice", and planned to do
research for a "plague antidote" out of his home in Lancaster,
Ohio.
-
- Harris pled guilty to one count of wire fraud, and was
placed on probation. The CDC later tightened up requirements for shipping
special disease agents and toxins, such as bubonic plague, tularemia and
brucellosis.
-
-
- New York City subway. Photo: Hans G. Andersson
-
- According to federal prosecutors, Harris once informed
a person that he had plans to attack the New York City subway system with
light bulbs filled with bubonic plague, using the same method that the
U.S. Army used in a test with harmless simulant bacteria in 1966. He forecasted
hundreds of thousands of victims and that the government of Iraq would
be blamed for the attack.
-
- <http://www.biohazardnews.net/scen_anthrax.htm#subway>
- Read about the NYC subway test in 1966
-
- Larry Wayne Harris has published detailed instructions
on how to obtain bubonic plague and other disease agents and use them as
biological weapons. He's considered dangerous by the U.S. government.
-
- "Given the availability of Y pestis around the world,
capacity for its mass production and aerosol dissemination, difficulty
in preventing such activities, high fatality rate of pneumonic plague,
and potential for secondary spread of cases during an epidemic, the potential
use of plague as a biological weapon is of great concern."
-
- Plague as a Biological Weapon: Medical & Public Health
Management, A Consensus Statement of the Johns Hopkins Working Group on
Civilian Biodefense, The Journal of the American Medical Association (JAMA)
Vol. 283 No. 17, May 3, 2000.
-
- MORE ABOUT PLAGUE
-
- BioHazard News: <http://www.biohazardnews.net/scen_plague.htm>Role-playing
Scenarios on Plague
-
- Plague as a Biological Weapon: Medical & Public
Health Management
- The Journal of the American Medical Association (JAMA)
Vol. 283 No. 17, May 3, 2000. A Consensus Statement of the Johns Hopkins
Working Group on Civilian Biodefense. To be used as a practical guide for
professionals dealing with medical and public health issues associated
with the use of plague as a biological weapon. <http://jama.ama-assn.org/issues/v283n17/abs/jst90013.html>
- Abstract
-
- <http://www.hopkins-biodefense.org/pages/agents/agentplague.html>
- Fact Sheet with consensus recommendations of the Johns
Hopkins Working Group on Civilian Biodefense regarding appropriate medical
and public health measures to be taken following such an attack.
-
- <http://www.ci.nyc.ny.us/html/doh/html/cd/plaguemd.html>
- Medical Treatment and Response to Suspected Plague: Information
for Health Care Providers During Biologic Emergencies
- Draft from July 2000, by New York City Department of
Health Bureau of Communicable Disease. A guide and reference source for
medical and public health professionals.
-
- <http://www.cdc.gov/ncidod/dvbid/plague/index.htm>
- CDC Plague Home Page
- A great online source for information about plague.
-
- <http://www.biohazardnews.net/lit.htm#nardo>
- The Black Death, edited by Don Nardo.
-
- <http://www.biohazardnews.net/lit.htm#epidemics>
- Epidemics, by Geoffrey Marks and William K. Beatty. A
historical perspective on epidemics, including plague.
-
- <http://www.biohazardnews.net/lit.htm#betrayal>
- Betrayal of Trust: The Collapse of Global Public Health,
by Laurie Garrett. Includes a good report from the pneumonic plague outbreak
in India, 1994.
-
- <http://www.discovery.com/stories/history/blackdeath/blackdeath.html>
Discovery: The Black Death
- Follow the rat and learn more details about the history
of bubonic plague.
-
-
- http://www.biohazardnews.net/agent_plague.htm
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