Bubonic plague

Resources

Bubonic plague is a disease that is typically passed from rodents to other animals and humans via the bite of a flea. The flea acquires the bacterium that causes the disease as it lives on the skin of the rodent. Humans can also acquire the disease by direct contact with infected tissue. The bacterium is called Yersinia pestis, after one of its co-discoverers, Alexandre Yersin.

The disease is named because of the symptoms. The bacterial infection produces a painful swelling of the lymph nodes. These are called buboes. Often the first swelling is evident in the groin. During the Middle Ages, an huge epidemic of bubonic plague was referred to as the Black Death, because of the blackening of the skin due to the dried blood that accumulated under the skin’s surface.

The bubonic plague has been a significant cause of misery and death throughout recorded history. The Black Death was only one of many epidemics of plague that extend back to the beginning of recorded history. Biblical descriptions of some disease outbreaks likely involved bubonic plague. The first recorded outbreak of bubonic plague was in AD 542–543. This plague destroyed the attempts of the Roman emperor of the day to re-establish a Roman empire in Europe. This is only one example of how bubonic plague has changed the course of history.

The plague of London in 1665 killed over 17,000 people (almost twenty percent of the city’s population). This outbreak was quelled by a huge fire that destroyed most of the city.

The disease remains present to this day. In North America, the last large epidemic occurred in Los Angeles in 1925. With the advent of the antibiotic era, bubonic plague has been controlled in the developed world. However, sporadic cases (e.g., 10 to 15 cases each year) still occur in the western United States. In less developed countries (e.g., in Africa, Bolivia, Peru, Ecuador, Brazil) thousands of cases are reported each year.

The infrequent outbreaks of bubonic plague does not mean the disease disappears altogether. Rather, the disease normally exists in what is called an enzootic state. That is, a few individuals of a certain community (e.g., rodents) harbor the disease. Sometimes, however, environmental conditions cause the disease to spread through the carrier population, causing loss of life. As the rodent populations dies, the fleas that live on them need to find other food sources. This is when the interaction with humans and non-rodent animals can occur. Between outbreaks, Yersinia pestis

infects rodents without causing much illness. Thus, the rodents become a reservoir of the infection.

Yersinia pestis is an intracellular parasite. In contrast to other kinds of bacteria, it enters cells. The bacterium that causes tuberculosis is also an intracellular parasite, as is the bacterium that causes chlamydia, a sexually transmitted disease.

Humans are not the “first choice” of host for Yersinia pestis. The Yersinia pestis bacterium infects the bloodstream of rats and other wild rodents such as squirrels and prairie dogs. Humans become infected only through the bite of a flea that has ingested blood from an infected rodent. Another route of transmission is through person-to-person contact. If a person’s lungs are infected with the bacteria, the disease can be transmitted easily to another person through a cough or a sneeze. This form of transmission is extremely quick: cases have been recorded of persons dying from the disease within 24 hours of exposure to an infected person.

Symptoms of infection in humans begin within days after contamination with the plague bacterium. The bacteria enter the bloodstream and travels to various organs (e.g., kidney, liver, spleen, lungs) as well as to the brain. In humans, plague can take two forms. One form, called the bubonic form, usually results from a flea bite and is characterized by a sore called a bubo. The bubo is actually the infected lymph node that drains the area through which the bacteria was introduced by the infected flea. The lymph node enlarges and turns black. Other symptoms of this form of plague include fever and congestion of the blood vessels of the eye. As the disease progresses, the bacteria spread to other parts of the body, resulting in septicemia, or widespread infection. The fatality rate of the bubonic plague is 15%.

In another form of plague, called the pneumonic form, the bacteria infect the lungs. This form of plague can follow the bubonic form, as the bacteria spreads to the lungs. Or, a person may simply contract the pneumonic form only, and show no evidence of a bubo. The pneumonic form is highly contagious and especially virulent: the average length of time from the first appearance to symptoms to death is less than two days.

If the infection is untreated, the death rate in humans approaches 75%. Prompt treatment most often leads to full recovery and a life-long immunity from further infection. Prevention is possible, since a vaccine is available. Unfortunately, the vaccine is protective for only a few months. Use of the vaccine is usually reserved for those who will be at high risk for acquiring the bacterial infection (e.g., soldiers, travelers to an outbreak region). Antibiotics such as tetracycline or sulfonamide are used more commonly as a precaution for those who might be exposed to the bacterium. Such use of antibiotics should be stopped once the risk of infection is gone, to avoid the development of resistance in other bacteria resident in the body.

These modern day treatment and preventative measures are a marked improvement from earlier times. In the fourteenth century, treatments included bathing in human urine, wearing feces, having a dead animal present in the home, and drinking concoctions of molten gold and crushed emeralds. As time progressed, even though the cause of the disease was still unknown, the preventative measures became more constructive. By the fifteenth century, for example, incoming ships were required to anchor offshore for 40 days before cargo or people could disembark. Quarantine is still practiced today as a protective measure for some diseases.

Another way to prevent plague is to control rodent and flea populations in cities. Fleas are easier to control than rodents, since most homes can be easily decontaminated. Many cities, especially in the United States, have instituted rodent-control programs aimed at decreasing the numbers of rodents that roam the streets. Since rodents also carry rabies and other deadly diseases, controlling their numbers makes sense for a variety of reasons.

Resources

BOOKS

Cantor, Norman F. In the Wake of the Plague: The Black Death and the World It Made. New York: Perennial, 2002.

Chase, Marilyn. The Barbary Plague: The Black Death in Victorian San Francisco. New York: Random House, 2004.

Kelly, Norman. The Great Mortality: An Initimate History of the Black Death, the Most Devastating Plague of All Time. New York: Harper Collins, 2005.

Kathleen Scogna

Bubonic Plague

█ BRIAN HOYLE

A concern of health and defense officials is the possible deliberate introduction of plague—or the exploitation of plague—as a terrorist weapon. Plague causing microorganisms are highly lethal, highly transmissible, and relatively easy to develop as terrorist weapons.

Bubonic plague is transmitted via fleas infected with Yersinia pestis. Pneumonic plague results from plague bacterium investing lung tissue. Pneumonic plague exhibits an airborne form of transmission. Infection occurs from breathing aerosolized bacteria. Untreated pneumonic plague is highly lethal.

Bubonic plague is a disease that is typically passed from rodents to other animals and humans via the bite of a flea. The flea acquires the bacterium that causes the disease as it lives on the skin of the rodent. Humans can also acquire the disease by direct contact with infected tissue.

The bacterium Pasteurella pestis is also known as Yersinia pestis, after one of its co-discoverers, Alexandre Yersin.

Prior to 1970, both United States and Soviet biological weapons programs developed techniques that enabled weapons developers to aerosolize plague particles.

Bubonic plague is named because of the symptoms. The bacterial infection produces a painful swelling of the lymph nodes. These are called buboes. Often the first swelling is evident in the groin. During the Middle Ages, a pandemic of bubonic plague was referred to as the Black Death, because of the blackening of the skin due to the dried blood that accumulated under the skin's surface.

The bubonic plague has been a significant cause of misery and death throughout recorded history. The Black Death is only one of many epidemics of plague that extended back to the beginning of recorded history. The first recorded outbreak of bubonic plague was in 542–543. This plague destroyed the attempts of the Roman emperor of the day to re-establish a Roman empire in Europe. This is only one example of how bubonic plague has changed the course of history.

The plague of London in 1665 killed over 17,000 people (almost twenty percent of the city's population). This outbreak was quelled by a huge fire that destroyed most of the city.

The disease remains present to this day. In North America, the last large epidemic occurred in Los Angeles in 1925. With the advent of the antibiotic era, bubonic plague has been controlled in the developed world. However, sporadic cases (e.g., 10 to 15 cases each year) still occur in the western United States. In less developed countries (e.g., in Africa, Bolivia, Peru, Ecuador, Brazil) thousands of cases are reported each year.

The infrequency of bubonic plague outbreaks does not mean the disease disappears altogether. Rather, the disease normally exists in what is called an enzootic state. That is, a few individuals of a certain community (e.g., rodents) harbor the disease. Sometimes, however, environmental conditions cause the disease to spread through the carrier population, causing loss of life. As the rodent populations dies, the fleas that live on them need to find other food sources. This is when the interaction with humans and non-rodent animals can occur. Between outbreaks, Yersinia pestis infects rodents without causing much illness. Thus, the rodents become a reservoir of the infection.

Symptoms of infection in humans begin within days after contamination with the plague bacterium. The bacteria enter the bloodstream and travel to various organs (e.g., kidney, liver, spleen, lungs) as well as to the brain. Symptoms include shivering, nausea with vomiting, headache, intolerance to light, and a whitish-appearing tongue. Buboes then appear, followed by rupture of blood vessels. The released blood can coagulate and turn black.

If the infection is untreated, the death rate in humans approaches 75%. Prompt treatment most often leads to full recovery and a life-long immunity from further infection. Prevention is possible, since a vaccine is available. Unfortunately, the vaccine is protective for only a few months. Use of the vaccine is usually reserved for those who will be at high risk for acquiring the bacterial infection (e.g., soldiers, travelers to an outbreak region). Antibiotics such as tetracycline or sulfonamide are used more commonly as a precaution for those who might be exposed to the bacterium. Such use of antibiotics should be stopped once the risk of infection is gone, to avoid the development of resistance in other bacteria resident in the body.

The most effective way to prevent bubonic plague is the maintenance of adequate sanitary conditions. This acts to control the rodent population, especially in urban centers.

In 1970, a World Health Organization study concluded that deliberate dissemination of 110 lbs (50 kg) of aerosolized Y pestis over a city with a population of approximately 5 million people could potentially result in 150,000 cases of pneumonic plague. Half of these cases would require advanced medical care and approximately 20% would be expected to perish.

█ FURTHER READING:

BOOKS:

Campbell, G. L., and D. T. Dennis. "Plague and other Yersinia infections." In: D. L. Kasper, et al; eds. Harrison's Principles of Internal Medicine, 14th ed. New York: McGraw Hill, 1998.

Dennis, D. T., N. Gratz, J. D. Poland, and E. Tikhomirov. Plague Manual: Epidemiology, Distribution, Surveillance and Control. Geneva: World Health Organization, 1999.

Frist, W. H. When Every Moment Counts: What You Need to Know about Bioterrorism from the Senates Only Doctor. Lanham, MD: Rowman & Littlefield, 2002.

Henderson, D.A., and T.V. Inglesby. Bioterrorism: Guidelines for Medical and Public Health Management. Chicago: American Medical Association, 2002.

Inglesby, Thomas V. "Bioterrorist Threats: What the Infectious Disease Community Should Know about Anthrax and Plague." Emerging Infections 5. Washington, D.C.: American Society for Microbiology Press, 2001.

PERIODICALS:

Kaufmann, A. F., M. I. Meltzer, and G. P. Schmid. "The Economic Impact of a Bioterrorist Attack: Are Prevention and Postattack Intervention Program Justifiable?" Emerging Infectious Diseases no. 3 (1997): 83–94.

SEE ALSO

Antibiotics
Biocontainment Laboratories
Biological and Toxin Weapons Convention
Biological Warfare
Biological Weapons, Genetic Identification
Bioterrorism, Protective Measures
Chemical and Biological Defense Information Analysis Center (CBIAC)
Chemical and Biological Detection Technologies
Pathogen Transmission
Pathogens
Weapons of Mass Destruction

Bubonic plague

Bubonic plague is a contagious, deadly disease caused by the bacterium Yersinia pestis. Sometimes referred to simply as "the plague," this disease has played a major role in world history. Because plague is highly contagious, it is easily transmitted from one person to another. Worldwide epidemics of the disease (called pandemics) have decimated populations since a.d. 542, when the first evidence of plague was recorded. Plague is rarely seen in the United States today, but is still epidemic in Southeast Asia .

Transmission of bubonic plague bacteria

Yersinia pestis is an intracellular parasite. In contrast to other kinds of bacteria , it enters cells. The bacterium that causes tuberculosis is also an intracellular parasite, as is the bacterium that causes chlamydia, a sexually transmitted disease.

Humans are not the "first choice" of host for Yersinia pestis. The Yersinia pestis bacterium infects the bloodstream of rats and other wild rodents such as squirrels and prairie dogs. Humans become infected only through the bite of a flea that has ingested blood from an infected rodent. Another route of transmission is through person-to-person contact. If a person's lungs are infected with the bacteria, the disease can be transmitted easily to another person through a cough or a sneeze. This form of transmission is extremely quick: cases have been recorded of persons dying from the disease within 24 hours of exposure to an infected person.

Symptoms of bubonic plague

In humans, plague can take two forms. One form, called the bubonic form, usually results from a flea bite and is characterized by a sore called a bubo. The bubo is actually the infected lymph node that drains the area through which the bacteria was introduced by the infected flea. The lymph node enlarges and turns black. Other symptoms of this form of plague include fever and congestion of the blood vessels of the eye . As the disease progresses, the bacteria spread to other parts of the body, resulting in septicemia, or widespread infection . The fatality rate of the bubonic plague is 15%.

In another form of plague, called the pneumonic form, the bacteria infect the lungs. This form of plague can follow the bubonic form, as the bacteria spreads to the lungs. Or, a person may simply contract the pneumonic form only, and show no evidence of a bubo. The pneumonic form is highly contagious and especially virulent: the average length of time from the first appearance to symptoms to death is less than two days.

For both types of plague, antibiotics can cure the disease. A vaccine is also available to protect those who are at risk of contracting plague. People who work with Yersinia pestis in laboratories and in environments where wild rodents are infected with the bacteria usually are vaccinated against plague. United States soldiers who fought in the Vietnam war in the 1960s and 1970s were vaccinated against plague. However, the vaccine only protects against the bubonic form, not the pneumonic form. People who are exposed to the pneumonic disease should take antibiotics as a precautionary measure.

Plague pandemics

Plague has played a major role in world history. Some evidence exists that a plague pandemic took place about 2,000 years ago, but the first recorded pandemic of plague occurred in a.d. 542 in Egypt and Ethiopia. This pandemic killed 100 million people.

The next great plague pandemic occurred in the fourteenth century in Europe , Central Asia, the North East, India, and China. In this pandemic, trading ships from China carried infected rats to Europe. About 25 million people in Europe alone died from plague; some experts estimate that this number constitutes a third of the European population. Because so many people died, the plague had a major impact on the economy and political structure of Europe. The scarcity of workers led to a scarcity of food; workers, previously given little compensation for their labors, began to demand higher wages. Some historians feel that the unrest of workers and the middle class in Europe that culminated in the beheading of King Charles I in England in the seventeenth century and the beheading of Louis XVI in France in the eighteenth century had its roots in the economic aftermath of the fourteenth plague pandemic.

The third plague pandemic began in Burma in 1894; from there, the plague spread to China and through Hong Kong to North America . One hundred million people in India died from plague over a period of 20 years. During this pandemic, the United States saw its first case of plague in 1900 in San Francisco. In 1907, 167 cases of plague in San Francisco were recorded. As a result of the pandemic, rats and other wild rodents in the areas around San Francisco became reservoirs of Yersinia pestis. Today, isolated cases of plague are still found in Kansas, Oklahoma, and Texas. The majority of cases worldwide (90%) occur in Southeast Asia: Burma, South Vietnam, Nepal, and Indonesia. Brazil also has a high number of plague cases. A recent outbreak in Surat, India, in 1994, killed 56 people and caused widespread panic.

Prevention

Plague pandemics can be prevented by the disinfection of ships, aircraft , and persons who are known to have the plague. The classic route of transmission that leads to pandemics is the transportation of infected rodents aboard transcontinental vehicles. Since many countries have instituted rigorous disinfection practices for ships and planes, plague cases have dropped dramatically.

If a person is diagnosed with plague, most countries, including the United States, require that the governmental health agency be notified. The person is usually kept under strict quarantine until the disease is brought under control with antibiotics.

Another way to prevent plague is to control rodent and flea populations in cities. Fleas are easier to control than rodents, since most homes can be easily decontaminated. Many cities, especially in the United States, have instituted rodent-control programs aimed at decreasing the numbers of rodents that roam the streets. Since rodents also carry rabies and other deadly diseases, controlling their numbers makes sense for a variety of reasons.

Resources

books

Cantor, Norman F. In the Wake of the Plague: The Black Death and the World It Made. New York: Perennial, 2002.

Nelson, K.E., C.M. Williams, and N.M.H. Graham. InfectiousDisease Epidemiology: Theory and Practice. Gaithersburg: Aspen Publishers, 2001.

periodicals

Epstein, Richard. "A Persistent Pestilence." GeographicalMagazine 63 (April 1994): 18.

Jayaramen, K.S. "Indian Plague Poses Enigma to Researchers." Nature (October 13, 1994): 547.

Mee, Charles L. "How a Mysterious Disease Laid Low Eu rope's Masses." Smithsonian (February 1990): 66.

Richardson, Sarah. "The Return of the Plague." Discover 16 (January 1995): 69.

Kathleen Scogna

Bubonic plague

Bubonic plague is a disease that is typically passed from rodents to other animals and humans via the bite of a flea. The flea acquires the bacterium that causes the disease as it lives on the skin of the rodent. Humans can also acquire the disease by direct contact with infected tissue. The bacterium is called Yersinia pestis, after one of its co-discoverers, Alexandre Yersin.

The disease is named because of the symptoms. The bacterial infection produces a painful swelling of the lymph nodes. These are called buboes. Often the first swelling is evident in the groin. During the Middle Ages, an huge epidemic of bubonic plague was referred to as the Black Death, because of the blackening of the skin due to the dried blood that accumulated under the skin's surface.

The bubonic plague has been a significant cause of misery and death throughout recorded history. The Black Death was only one of many epidemics of plague that extend back to the beginning of recorded history. Biblical descriptions of some disease outbreaks likely involved bubonic plague. The first recorded outbreak of bubonic plague was in 542–543. This plague destroyed the attempts of the Roman emperor of the day to re-establish a Roman empire in Europe. This is only one example of how bubonic plague has changed the course of history.

The plague of London in 1665 killed over 17,000 people (almost twenty percent of the city's population). This outbreak was quelled by a huge fire that destroyed most of the city.

The disease remains present to this day. In North America, the last large epidemic occurred in Los Angeles in 1925. With the advent of the antibiotic, era bubonic plague has been controlled in the developed world. However, sporadic cases (e.g., 10 to 15 cases each year) still occur in the western United States. In less developed countries (e.g., in Africa, Bolivia, Peru, Ecuador, Brazil) thousands of cases are reported each year.

The infrequent outbreaks of bubonic plague does not mean the disease disappears altogether. Rather, the disease normally exists in what is called an enzootic state. That is, a few individuals of a certain community (e.g., rodents) harbor the disease. Sometimes, however, environmental conditions cause the disease to spread through the carrier population, causing loss of life. As the rodent populations dies, the fleas that live on them need to find other food sources. This is when the interaction with humans and non-rodent animals can occur. Between outbreaks, Yersinia pestis infects rodents without causing much illness. Thus, the rodents become a reservoir of the infection.

Symptoms of infection in humans begin within days after contamination with the plague bacterium. The bacteria enter the bloodstream and travels to various organs (e.g., kidney, liver, spleen, lungs) as well as to the brain. Symptoms include shivering, nausea with vomiting, headache, intolerance to light, and a whitish-appearing tongue. Buboes then appear, followed by rupture of blood vessels. The released blood can coagulate and turn black.

If the infection is untreated, the death rate in humans approaches 75%. Prompt treatment most often leads to full recovery and a life-long immunity from further infection. Prevention is possible, since a vaccine is available. Unfortunately, the vaccine is protective for only a few months. Use of the vaccine is usually reserved for those who will be at high risk for acquiring the bacterial infection (e.g., soldiers, travelers to an outbreak region). Antibiotics such as tetracycline or sulfonamide are used more commonly as a precaution for those who might be exposed to the bacterium. Such use of antibiotics should be stopped once the risk of infection is gone, to avoid the development of resistance in other bacteria resident in the body.

These modern day treatment and preventative measures are a marked improvement from earlier times. In the fourteenth century, treatments included bathing in human urine, wearing feces, having a dead animal present in the home, and drinking concoctions of molten gold and crushed emeralds. As time progressed, even though the cause of the disease was still unknown, the preventative measures became more constructive. By the fifteenth century, for example, incoming ships were required to anchor offshore for 40 days before cargo or people could disembark. Quarantine is still practiced today as a protective measure for some diseases.

The most effective way to prevent bubonic plague is the maintenance of adequate sanitary conditions. This acts to control the rodent population, especially in urban centers.

See also Bacteria and bacterial infection; Epidemics and pandemics; Zoonoses

Bubonic Plague

Bubonic plague is an infectious disease. Thus, it is a concern in forensic science as a possible cause of death during an occurrence or outbreak featuring an unknown pathogen (illness-causing agent).

The bacterium that is responsible for bubonic plague is Yersinia pestis, named after one of its co-discoverers, Alexandre Yersin, and is also known as Pasteurella pestis. Typically, the bacterium is passed from rodents to other animals and humans via the bite of a flea. The flea acquires the bacterium as it lives on the skin of the rodent. Humans can also acquire the disease by direct contact with infected tissue or fluids .

Pneumonic plague (infection with Yersinia pestis bacteria in the lungs) results from inhaling minute droplets of moisture in the air that are contaminated with the bacteria, usually from being near another person with pneumonic plague who is coughing.

With bubonic plague, Yersinia pestis invades the lymphatic system. Bubonic plague is named because of the symptoms. The bacterial infection produces a painful swelling of the lymph nodes. These are called buboes. Often, the first swelling is evident in the groin. During the Middle Ages, a large epidemic of bubonic plague was referred to as the Black Death, because of the blackening of the skin due to the dried blood that accumulated under the skin's surface.

The bubonic plague has been a significant cause of misery and death throughout recorded history. The Black Death was only one of many epidemics of plague that extend back to the beginning of recorded history. The first recorded outbreak of bubonic plague was in 542–543. This plague destroyed the attempts of the Roman emperor of the day to reestablish a Roman empire in Europe. This is only one example of how bubonic plague has changed the course of history.

The plague of London in 1665 killed over 17,000 people (almost twenty percent of the city's population). This outbreak was quelled by a huge fire that destroyed most of the city.

The disease remains present to this day. In North America, the last large epidemic occurred in Los Angeles in 1925. With the advent of the antibiotic era, bubonic plague has been controlled in the developed world. However, sporadic cases (e.g., 10–15 cases each year) still occur in the western United States. In less developed countries (e.g., in Africa, Bolivia, Peru, Ecuador, Brazil), thousands of cases are reported each year.

The infrequent outbreaks of bubonic plague do not mean the disease disappears altogether. Rather, the disease normally exists in what is called an enzootic state. That is, a few individuals of a certain community (e.g., rodents) harbor the disease. Sometimes, however, environmental conditions cause the disease to spread through the carrier population, causing loss of life. As the rodent populations dies, the fleas that live on them need to find other food sources. This is when the interaction with humans and non-rodent animals can occur. Between outbreaks, Yersinia pestis infects rodents without causing much illness. Thus, the rodents become a reservoir of the infection.

Symptoms of infection in humans begin within days after contamination with the plague bacterium. The bacteria enter the bloodstream and travel to various organs (e.g., kidney, liver, spleen, lungs) as well as to the brain. Symptoms include shivering, nausea with vomiting, headache, intolerance to light, and a whitish-appearing tongue. Buboes then appear, followed by rupture of blood vessels. The released blood can coagulate and turn black.

If the infection is untreated, the death rate from plague in humans approaches 75%. Prompt treatment most often leads to full recovery and a life-long immunity from further infection. Prevention is possible, since a vaccine is available. Unfortunately, the vaccine is protective for only a few months. Use of the vaccine is usually reserved for those who will be at high risk for acquiring the bacterial infection (e.g., soldiers, travelers to an outbreak region). Antibiotics such as tetracycline or sulfonamide are used more commonly as a precaution for those who might be exposed to the bacterium. Such use of antibiotics should be stopped once the risk of infection is gone, to avoid the development of resistance in other bacteria resident in the body.

The most effective way to prevent bubonic plague is the maintenance of adequate sanitary conditions. This acts to control the rodent population, especially in urban centers.

see also Biodetectors; Bioterrorism; Nervous system overview; Pathogens; Toxins.