Minus Related Pages. Forms of plague. Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link. CDC is not responsible for Section compliance accessibility on other federal or private website. Bubonic plague is the most common variety of the disease. It's named after the swollen lymph nodes buboes that typically develop in the first week after you become infected.
Buboes may be:. Septicemic plague occurs when plague bacteria multiply in your bloodstream. Signs and symptoms include:. Pneumonic plague affects the lungs. It's the least common variety of plague but the most dangerous, because it can be spread from person to person via cough droplets.
Signs and symptoms can begin within a few hours after infection, and may include:. Pneumonic plague progresses rapidly and may cause respiratory failure and shock within two days of infection. Pneumonic plague needs to be treated with antibiotics within a day after signs and symptoms first appear, or the infection is likely to be fatal. If you begin to feel ill and have been in an area where plague has been known to occur, seek immediate medical attention. You'll need treatment with medication to prevent serious complications or death.
In the United States, plague has been transmitted to humans in several western and southwestern states — primarily New Mexico, Arizona, California and Colorado. Worldwide, plague is most common in rural and semirural parts of Africa especially the African island of Madagascar , South America and Asia.
Then for 20 to 22 days, you were. You only knew you were infected when you fell ill, for the final five days or less-but by then you had been infecting people unknowingly for weeks. Europeans at the time clearly knew the disease had a long, infectious incubation period, because they rapidly imposed measures to isolate potential carriers. For example, they stopped anyone arriving on a ship from disembarking for 40 days, or quarantina in Italian — -the origin of the word quarantine.
Epidemiologists know that diseases with a long incubation time create outbreaks that last months. From 14th-century ecclesiastical records, Scott and Duncan estimate that outbreaks of the Black Death in a given town or diocese typically lasted 8 or 9 months. That, plus the delay between waves of cases, is the fingerprint of the disease across Europe over seasons and centuries, they say. The pair found exactly the same pattern in 17th-century outbreaks in Florence, Milan and a dozen towns across England, including London, Colchester, Newcastle, Manchester and Eyam in Derbyshire.
In , the inhabitants of Eyam selflessly confined themselves to the village. A third of them died, but they kept the disease from reaching other towns. This would not have worked if the carriers were rats. Despite the force of their argument, Scott and Duncan have yet to convince their colleagues. None of the experts that New Scientist spoke to had read their book, and a summary of its ideas provoked reactions that range from polite interest to outright dismissal.
Human fleas can keep it in their guts for a few weeks, leading to a delay in spread. But this would be unlikely to have happened the same way every time. Moreover, people with enough Yersinia in their blood for a flea to pick it up are already very sick. They would only be able to pass their infection on in this way for a very short time-and whoever the flea bit would also sicken within a week, the incubation time of Yersinia.
This does not fit the pattern documented by Scott and Duncan. Neither would an extra-virulent Yersinia, which would still depend on rats. There have been several other ingenious attempts to save the Yersinia theory as inconsistencies have emerged.
Many fall back on pneumonic plague, a variant form of Yersinia infection. This can occur in the later stages of bubonic plague, when the bacteria sometimes proliferate in the lungs and can be coughed out, and inhaled by people nearby. Untreated pneumonic plague is invariably fatal and can spread directly from person to person.
Yet the Black Death typically jumped between towns in the time a healthy human took to travel. Also, pneumonic plague kills quickly-within six days, usually less. The Yersinia pestis bacteria that circulate and cause plague today are remarkably similar to the bacteria researchers have identified as the cause of the Black Death. It's just that today, we live in an era of antibiotics — as long as the disease is caught early, we can treat it. It's possible that people can catch plague from direct contact with infected animals, according to the New Mexico Department of Health, but fleas are still usually the link between infected rodents and humans.
In wild rodent populations that harbor the bacteria, plague can thrive for a long time before humans come into contact with it.
In the American West, where most US cases occur, there are a number of rodents — from rats to voles to prairie dogs — that are susceptible to plague, Ken Gage, a researcher focused on vector-borne disease at the Centers for Disease Control and Prevention, told NPR in In rural areas with semi-arid forests and grasslands, these animals spread the disease amongst themselves.
But they can also jump on humans, or on dogs or coyotes or cats, which aren't the right hosts, but unfortunately those animals can be bitten by the fleas and get plague. Still, the US only gets a handful of cases — usually between one and 17 every year.
Plague is a bigger problem in places that have a harder time shutting down outbreaks. In the US, disease detectives try to find every person an infected individual came into contact with.
That's harder in regions with humanitarian crises or ongoing conflicts, according to the World Health Organization.
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