The plague is one of the deadliest bacterial infections in human history. Cases still occur today

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One of the deadliest bacterial infections in human history, the plague, known as the Black Death, caused an estimated 50 million deaths in Europe during the Middle Ages.

Although the disease is extremely rare, it still exists today, with one person found to have the disease in New Mexico. died of plague in March after being hospitalized due to the disease and one person in Oregon suffering from bubonic plague He died in February, possibly contracting the infection from his pet cat.

It is spread by fleas that live on rats. Symptoms usually appear within one to seven days of infection and include painful, swollen lymph nodes, called buboes, in the groin, armpit or neck areas, as well as fever, chills and cough.

Plague affects humans and other mammals.

People usually get plague through the bite of a rat infected with the bacterium Yersinia pestis, which causes plague, or by touching an infected animal. U.S. Centers for Disease Control and Prevention.

Cats that become sick themselves can infect humans directly, while more adventurous dogs can easily carry fleas back to their owners. People can also become sick by breathing in droplets coughed out by an infected person or animal.

According to the CDC, the bacteria persists because it continues to circulate at low levels in certain rodent populations. These infected animals and their fleas serve as long-term reservoirs for the bacteria.

“The reason it hasn’t been eradicated is because it exists in animal reservoirs,” said Dr. Dan Baruch, director of the Virology and Vaccine Research Center at Beth Israel Deaconess Medical Center. said in february“This bacteria can infect animals, and because we cannot treat all animals in the wild, it persists in nature and thus occasionally infects a limited number of humans.”

Plague occurs naturally in rural areas of the western United States, particularly in Arizona, California, Colorado, and New Mexico. That’s where an average of seven human plague cases are reported to the CDC each year. But far more cases occur in parts of Africa and Asia.

According to the report, 3,248 cases were reported worldwide from 2010 to 2015, including 584 deaths. World Health Organization, It said the three most affected countries were the Democratic Republic of the Congo, Madagascar and Peru.

There are three types of plague – bubonic, septicemic and pneumonic plague. With the pneumonic form of plague – which means it affects the lungs – there is a risk of direct transmission from human to human. Such was the case A massive outbreak occurred in Madagascar in 2017There were 2,348 confirmed, probable and suspected cases and 202 deaths.

The CDC reports that the last urban plague epidemic in the United States occurred in Los Angeles between 1924 and 1925.

Modern antibiotics – streptomycin is the usual first-line treatment – can prevent complications and death if given soon after symptoms appear. This treatment is used for the two most common types of plague: bubonic and pneumonic.

“The reason this disease caused such widespread death and destruction in the Middle Ages is because we didn’t have antibiotics at the time,” Barouch said. said in february About the plague.

“Although it can be a serious illness, it is usually easily treated with antibiotics, provided it is caught early. So it is now a very treatable disease. It should not cause people the same fear it did during the Black Death in the Middle Ages,” he said. “If someone develops symptoms consistent with plague – usually the early symptoms are fever, chills and swollen lymph nodes – seek medical help, because in the early stages, plague can be easily treated with antibiotics.”

Bubonic plague has a mortality rate of 30% to 60% if left untreated, while pneumonic plague is always fatal if left untreated. According to WHO.

However, a type of bubonic plague High-level resistance to streptomycin Has been seen in Madagascar.

More than 80% of cases in the United States are the bubonic form, which is the most common form of infection. Untreated bubonic plague can progress to the more severe pneumonic plague, which causes rapidly developing pneumonia after the bacteria spread to the lungs.

there is one Yersinia Pestis VaccineBut it’s only recommended for high-risk people such as scientists who work directly with the bacterium, said Dr. Harish Moorjani, an infectious disease specialist at Phelps Hospital in New York, which is part of Northwell Health, said in february,

“The vast majority of people don’t need the vaccine,” Moorjani said.

A 2019 Review The development of experimental plague vaccines shows that researchers are exploring different approaches to developing an effective plague vaccine.

Since different vaccine designs produce different mechanisms of immunity, the authors concluded that combining different types of vaccines could overcome the limitations of individual vaccines and effectively prevent potential plague outbreaks.

How do you keep yourself and your family safe?

Key steps to prevent plague include destroying rodent nesting sites, removing bushes, piles of stones, litter and excess firewood from around your home, shed, garage and recreation areas.

Report sick or dead animals to law enforcement or your local health officials; do not pick them up or touch them yourself. If you must handle a sick or dead animal, wear gloves.

If you live in an endemic area, Take extra precautionsUse insect repellents containing DEET to avoid flea bites and regularly treat dogs and cats for fleas. Do not sleep with your pets as this increases the risk of contracting the plague. Finally, your pets should not hunt or roam in rodent habitats, such as prairie dog colonies.

CNN’s Jacqueline Howard and Mira Cheng contributed to this report.