bubonic plague bubonic plague bubonic plague is one of three types of plague caused by the bacterium yersinia pestis. 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. this article is about the disease. for information about the medieval plague, see black death. bubonic plaguea bubo on the upper thigh of a person infected with bubonic plaguespecialtyinfectious diseasesymptomsfever, headaches, vomiting, swollen lymph nodescomplicationsgangrene, meningitisusual onset1–7 days after exposurecausesyersinia pestis spread by fleasdiagnostic methodfinding the bacterium in the blood, sputum, or lymph nodestreatmentantibiotics such as streptomycin, gentamicin, or doxycyclinefrequency650 cases reported a yeardeaths10% mortality with treatment30–90% if untreated the three types of plague are the result of the route of infection: bubonic plague, septicemic plague, and pneumonic plague. bubonic plague is mainly spread by infected fleas from small animals. it may also result from exposure to the body fluids from a dead plague-infected animal. mammals such as rabbits, hares, and some cat species are susceptible to bubonic plague, and typically die upon contraction. in the bubonic form of plague, the bacteria enter through the skin through a flea bite and travel via the lymphatic vessels to a lymph node, causing it to swell. diagnosis is made by finding the bacteria in the blood, sputum, or fluid from lymph nodes. prevention is through public health measures such as not handling dead animals in areas where plague is common. while vaccines against the plague have been developed, the world health organization recommends that only high-risk groups, such as certain laboratory personnel and health care workers, get inoculated. several antibiotics are effective for treatment, including streptomycin, gentamicin, and doxycycline. without treatment, plague results in the death of 30% to 90% of those infected. death, if it occurs, is typically within 10 days. with treatment, the risk of death is around 10%. globally between 2010 and 2015 there were 3,248 documented cases, which resulted in 584 deaths. the countries with the greatest number of cases are the democratic republic of the congo, madagascar, and peru. the plague is considered the likely cause of the black death that swept through asia, europe, and africa in the 14th century and killed an estimated 50 million people, including about 25% to 60% of the european population. because the plague killed so many of the working population, wages rose due to the demand for labor. some historians see this as a turning point in european economic development. the disease is also considered to have been responsible for the plague of justinian, originating in the eastern roman empire in the 6th century ce, as well as the third epidemic, affecting china, mongolia, and india, originating in the yunnan province in 1855. the term bubonic is derived from the greek word βουβών, meaning "groin". cause an oriental rat flea (xenopsylla cheopis) infected with the plague bacterium (yersinia pestis), which appears as a dark mass in the gut. the foregut of this flea is blocked by a y. pestis biofilm; when the flea attempts to feed on an uninfected host, y. pestis from the foregut is regurgitated into the wound, causing infection. bubonic plague is an infection of the lymphatic system, usually resulting from the bite of an infected flea, xenopsylla cheopis (the oriental rat flea). several flea species carried the bubonic plague, such as pulex irritans (the human flea), xenopsylla cheopis, and ceratophyllus fasciatus. xenopsylla cheopis was the most effective flea species for transmittal. in very rare circumstances, as in septicemic plague, the disease can be transmitted by direct contact with infected tissue or exposure to the cough of another human. the flea is parasitic on house and field rats and seeks out other prey when its rodent hosts die. rats were an amplifying factor to bubonic plague due to their common association with humans as well as the nature of their blood. the rat's blood allowed the rat to withstand a major concentration of the plague. the bacteria form aggregates in the gut of infected fleas and this results in the flea regurgitating ingested blood, which is now infected, into the bite site of a rodent or human host. once established, bacteria rapidly spread to the lymph nodes and multiply. the fleas that transmit the disease only directly infect humans when the rat population in the area is wiped out from a mass infection. furthermore, in areas of a large population of rats, the animals can harbor low levels of the plague infection without causing human outbreaks. with no new rat inputs being added to the population from other areas, the infection would only spread to humans in very rare cases of overcrowding. signs and symptoms necrosis of the nose, the lips, and the fingers and residual bruising over both forearms in a person recovering from bubonic plague that disseminated to the blood and the lungs. at one time, the person's entire body was bruised. after being transmitted via the bite of an infected flea, the y. pestis bacteria become localized in an inflamed lymph node, where they begin to colonize and reproduce. infected lymph nodes develop hemorrhages, which result in the death of tissue.y. pestis bacilli can resist phagocytosis and even reproduce inside phagocytes and kill them. as the disease progresses, the lymph nodes can hemorrhage and become swollen and necrotic. bubonic plague can progress to lethal septicemic plague in some cases. the plague is also known to spread to the lungs and become the disease known as the pneumonic plague. symptoms appear 2–7 days after getting bitten and they include: chills general ill feeling (malaise) high fever >39 °c (102.2 °f) muscle cramps seizures smooth, painful lymph gland swelling called a bubo, commonly found in the groin, but may occur in the armpits or neck, most often near the site of the initial infection (bite or scratch) pain may occur in the area before the swelling appears gangrene of the extremities such as toes, fingers, lips, and tip of the nose. the best-known symptom of bubonic plague is one or more infected, enlarged, and painful lymph nodes, known as buboes. buboes associated with the bubonic plague are commonly found in the armpits, upper femoral, groin, and neck region. symptoms include heavy breathing, continuous vomiting of blood (hematemesis), aching limbs, coughing, and extreme pain caused by the decay or decomposition of the skin while the person is still alive. additional symptoms include extreme fatigue, gastrointestinal problems, spleen inflammation, lenticulae (black dots scattered throughout the body), delirium, coma, organ failure, and death. organ failure is a result of the bacteria infecting organs through the bloodstream. other forms of the disease include septicemic plague and pneumonic plague in which the bacterium reproduces in the person's blood and lungs respectively. diagnosis laboratory testing is required in order to diagnose and confirm plague. ideally, confirmation is through the identification of y. pestis culture from a patient sample. confirmation of infection can be done by examining serum taken during the early and late stages of infection. to quickly screen for the y. pestis antigen in patients, rapid dipstick tests have been developed for field use.gram-negative yersinia pestis bacteria. the culture was grown over a 72-hour time period samples taken for testing include: buboes: swollen lymph nodes (buboes) characteristic of bubonic plague, a fluid sample can be taken from them with a needle. blood lungs prevention bubonic plague outbreaks are controlled by pest control and modern sanitation techniques. this disease uses fleas commonly found on rats as a vector to jump from animals to humans. the mortality rate hits its peak during the hot and humid months of june, july, and august. furthermore, the plague most affected those of poor upbringing due to greater exposure, poor sanitation techniques and lack of a healthy immune system due to a poor diet. the successful control of rat populations in dense urban areas is essential to outbreak prevention. one example is the use of a machine called the sulfurozador, used to deliver sulphur dioxide to eradicate the pest that spread the bubonic plague, in buenos aires, argentina during the early 18th century. targeted chemoprophylaxis, sanitation, and vector control also played a role in controlling the 2003 oran outbreak of the bubonic plague. another means of prevention in large european cities was a city-wide quarantine to not only limit interaction with people who were infected, but also to limit the interaction with the infected rats. treatment several classes of antibiotic are effective in treating bubonic plague. these include aminoglycosides such as streptomycin and gentamicin, tetracyclines (especially doxycycline), and the fluoroquinolone ciprofloxacin. mortality associated with treated cases of bubonic plague is about 1–15%, compared to a mortality of 40–60% in untreated cases. people potentially infected with the plague need immediate treatment and should be given antibiotics within 24 hours of the first symptoms to prevent death. other treatments include oxygen, intravenous fluids, and respiratory support. people who have had contact with anyone infected by pneumonic plague are given prophylactic antibiotics. using the broad-based antibiotic streptomycin has proven to be dramatically successful against the bubonic plague within 12 hours of infection. epidemiology main article: epidemiology of plague distribution of plague-infected animals, 1998 globally between 2010 and 2015, there were 3,248 documented cases, which resulted in 584 deaths. the countries with the greatest number of cases are the democratic republic of the congo, madagascar, and peru. for over a decade since 2001, zambia, india, malawi, algeria, china, peru, and the democratic republic of the congo had the most plague cases with over 1,100 cases in the democratic republic of the congo alone. from 1,000 to 2,000 cases are conservatively reported per year to the who. from 2012 to 2017, reflecting political unrest and poor hygienic conditions, madagascar began to host regular epidemics. between 1900 and 2015, the united states had 1,036 human plague cases with an average of 9 cases per year. in 2015, 16 people in the western united states developed plague, including 2 cases in yosemite national park. these us cases usually occur in rural northern new mexico, northern arizona, southern colorado, california, southern oregon, and far western nevada. in november 2017, the madagascar ministry of health reported an outbreak to the who (world health organization) with more cases and deaths than any recent outbreak in the country. unusually, most of the cases were pneumonic rather than bubonic. in june 2018, a child was confirmed to be the first person in idaho to be infected by bubonic plague in nearly 30 years. a couple died in may 2019, in mongolia, while hunting marmots. another two people in the province of inner mongolia, china were treated in november 2019 for the disease. spread of bubonic plague through time in europe (2nd pandemic) in july 2020, in bayannur, inner mongolia of china, a human case of bubonic plague was reported. officials responded by activating a city-wide plague-prevention system for the remainder of the year. also in july 2020, in mongolia, a teenager died from bubonic plague after consuming infected marmot meat. history yersinia pestis has been discovered in archaeological finds from the late bronze age (~3800 bp). the bacteria is identified by ancient dna in human teeth from asia and europe dating from 2,800 to 5,000 years ago. some authors have suggested that the plague was responsible for the neolithic decline. first pandemic the first recorded epidemic affected the sasanian empire and their arch-rivals, the eastern roman empire (byzantine empire) and was named the plague of justinian after emperor justinian i, who was infected but survived through extensive treatment. the pandemic resulted in the deaths of an estimated 25 million (6th century outbreak) to 50 million people (two centuries of recurrence). the historian procopius wrote, in volume ii of history of the wars, of his personal encounter with the plague and the effect it had on the rising empire. in the spring of 542, the plague arrived in constantinople, working its way from port city to port city and spreading around the mediterranean sea, later migrating inland eastward into asia minor and west into greece and italy. the plague of