The Black Death was a bubonic plague pandemic occurring in Afro-Eurasia from 1346 to 1353. It is the most fatal pandemic recorded in human history, causing the death of 75–200 million people in Eurasia and North Africa, peaking in Europe from 1347 to 1351. Bubonic plague is caused by the bacterium Yersinia pestis spread by fleas, but it can also take a secondary form where it is spread person-to-person contact via aerosols causing septicaemic or pneumonic plagues.
Plague is an infectious disease caused by the bacterium Yersinia pestis. Symptoms include fever, weakness and headache. Usually this begins one to seven days after exposure. There are three forms of plague, each affecting a different part of the body and causing associated symptoms. Pneumonic plague infects the lungs, causing shortness of breath, coughing and chest pain; bubonic plague affects the lymph nodes, making them swell; and septicemic plague infects the blood and can cause tissues to turn black and die.
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus. Other rat genera include Neotoma, Bandicota and Dipodomys.
Yersinia pestis is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both Yersinia pseudotuberculosis and Yersinia enterocolitica. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea. It causes the disease plague, which caused the first plague pandemic and the Black Death, the deadliest pandemic in recorded history. Plague takes three main forms: pneumonic, septicemic, and bubonic.
The brown rat, also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat, Norwegian rat and Parisian rat, is a widespread species of common rat. One of the largest muroids, it is a brown or grey rodent with a head and body length of up to 28 cm (11 in) long, and a tail slightly shorter than that. It weighs between 140 and 500 g. Thought to have originated in northern China and neighbouring areas, this rodent has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America. With rare exceptions, the brown rat lives wherever humans live, particularly in urban areas.
Pneumonic plague is a severe lung infection caused by the bacterium Yersinia pestis. Symptoms include fever, headache, shortness of breath, chest pain, and coughing. They typically start about three to seven days after exposure. It is one of three forms of plague, the other two being septicemic plague and bubonic plague.
Monkeypox is an infectious viral disease that can occur in humans and some other animals. Symptoms include fever, swollen lymph nodes, and a rash that forms blisters and then crusts over. The time from exposure to onset of symptoms ranges from 5 to 21 days. The duration of symptoms is typically 2 to 4 weeks. There may be mild symptoms, but it may occur without any symptoms being known. The classic presentation of fever and muscle pains, followed by swollen glands, with lesions all at the same stage, has not been found to be common to all outbreaks. Cases may be severe, especially in children, pregnant women or people with suppressed immune systems.
Tularemia, also known as rabbit fever, is an infectious disease caused by the bacterium Francisella tularensis. Symptoms may include fever, skin ulcers, and enlarged lymph nodes. Occasionally, a form that results in pneumonia or a throat infection may occur.
Septicemic plague is one of the three forms of plague, and is caused by Yersinia pestis, a gram-negative species of bacterium. Septicemic plague is a systemic disease involving infection of the blood, and is most commonly spread by bites from infected fleas. Septicemic plague can cause disseminated intravascular coagulation, and is almost always fatal when untreated. The other varieties of the plague are bubonic plague and pneumonic plague.
In infectious disease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally lives and reproduces, or upon which the pathogen primarily depends for its survival. A reservoir is usually a living host of a certain species, such as an animal or a plant, inside of which a pathogen survives, often without causing disease for the reservoir itself. By some definitions a reservoir may also be an environment external to an organism, such as a volume of contaminated air or water.
The third plague virus was a major bubonic plague pandemic that began in Yunnan, China, in 1855 during the fifth year of the Xianfeng Emperor of the Qing dynasty. This episode of bubonic plague spread to all inhabited continents, and ultimately led to more than 12 million deaths in India and China, with at least 10 million killed in India alone, making it one of the deadliest pandemics in history. According to the World Health Organization, the pandemic was considered active until 1960 when worldwide casualties dropped to 200 per year. Plague deaths have continued at a lower level for every year since.
Rat-bite fever (RBF) is an acute, febrile human illness caused by bacteria transmitted by rodents, in most cases, which is passed from rodent to human by the rodent's urine or mucous secretions. Alternative names for rat-bite fever include streptobacillary fever, streptobacillosis, spirillary fever, bogger, and epidemic arthritic erythema. It is a rare disease spread by infected rodents and caused by two specific types of bacteria:
- Streptobacillus moniliformis, the only reported bacteria that causes RBF in North America
- Spirillum minus, common in Asia. Most cases occur in Japan, but specific strains of the disease are present in the United States, Europe, Australia, and Africa.
Venezuelan equine encephalitis virus is a mosquito-borne viral pathogen that causes Venezuelan equine encephalitis or encephalomyelitis (VEE). VEE can affect all equine species, such as horses, donkeys, and zebras. After infection, equines may suddenly die or show progressive central nervous system disorders. Humans also can contract this disease. Healthy adults who become infected by the virus may experience flu-like symptoms, such as high fevers and headaches. People with weakened immune systems and the young and the elderly can become severely ill or die from this disease.
Seoul orthohantavirus (SEOV) is a member of the Orthohantavirus family of rodent-borne viruses and is one of the 4 hantaviruses that are known to be able to cause Hantavirus hemorrhagic fever with renal syndrome (HFRS). It is an Old World hantavirus; a negative sense, single-stranded, tri-segmented RNA virus.
Bubonic plague is one of three types of plague caused by the plague bacterium. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and vomiting, as well as swollen and painful lymph nodes occurring in the area closest to where the bacteria entered the skin. Acral necrosis, the dark discoloration of skin, is another symptom. Occasionally, swollen lymph nodes, known as "buboes," may break open.
Theories of the Black Death are a variety of explanations that have been advanced to explain the nature and transmission of the Black Death (1347–51). A number of epidemiologists from the 1980s to the 2000s challenged the traditional view that the Black Death was caused by plague based on the type and spread of the disease. The confirmation in 2010 and 2011 that Yersinia pestis DNA was associated with a large number of plague sites has led researchers to conclude that "Finally, plague is plague."
Monkeypox virus is a species of double-stranded DNA virus which causes monkeypox in humans and other animals. It belongs to the genus Orthopoxvirus in the family Poxviridae. Monkeypox virus is one of the human orthopoxviruses that includes variola (VARV), cowpox (CPX), and vaccinia (VACV) viruses. It is not a direct ancestor to, nor a direct descendant of, the variola virus, which causes smallpox. Monkeypox is similar to smallpox, but with a milder rash and lower mortality rate.
Beginning in May 2003, by July a total of 71 cases of human monkeypox were found in six Midwestern states including Wisconsin, Indiana (16), Illinois (12), Kansas (1), Missouri (2), and Ohio (1). The cause of the outbreak was traced to Gambian pouched rats imported from Ghana on April 9, 2003, into the United States by an exotic animal importer in Texas. The rats were shipped from Texas to an Illinois distributor, who housed them with prairie dogs.
Sylvatic plague is an infectious bacterial disease caused by the plague bacterium that primarily affects rodents, such as prairie dogs. It is the same bacterium that causes bubonic and pneumonic plague in humans. Sylvatic, or sylvan, means 'occurring in woodland,' and refers specifically to the form of plague in rural wildlife. Urban plague refers to the form in urban wildlife.
The 1924 Los Angeles pneumonic plague outbreak was an outbreak of the pneumonic plague in Los Angeles, California that began on September 28, 1924, and was declared fully contained on November 13, 1924. It represented the first time that the plague had emerged in Southern California; plague outbreaks previously surfaced in San Francisco and Oakland. The outbreak killed 30 people and infected several more. Public health officials credited the lessons learned from the San Francisco outbreak with saving lives, and swiftly implemented preventative measures, including hospitalization of the sick and all their contacts, a neighborhood quarantine, and a large-scale rat eradication program. The epicenter of the plague was in the Macy Street District, primarily home to Mexican immigrants. Racism against Mexican Americans tainted the reaction to the plague, an issue not made public until the outbreak concluded. This outbreak was the last instance of aerosol transmission of the plague and the last major plague outbreak in the United States.
