Swat Pest Blog



How Fleas Helped Spread the Black Plague

Wednesday, April 18th, 2012 by Brandon Runyon

Fleas who fed on rats spread the Black Plague in 1348, during the Middle Ages. Everyone blamed “bad air” for the pandemic that killed its victims. They either moved out of cities or stayed indoors, trying to avoid the pandemic.

They didn’t know the real culprit was living with them and on them. Rats infected with the plague had been brought from Eastern countries, some from Chinese traders and others as a result of Crusaders returning home. When fleas bit the infected rats, the fleas got infected. Plague-infected fleas drank more blood.

When the rats died, the plague-infected fleas went after people. Fleas were so common people didn’t notice them. The plague-infected fleas bit people and infected them with the Black or bubonic plague. A person infected with the Black Plague could then easily infect other people. A few recovered from a Black Plague infection, but most died a bloody, painful death a week after infection.

So Europe became a perfect storm of fleas infecting people at the same time people were infecting each other with the plague. Since no one eliminated the source of the problem – the fleas – the disease spread rapidly. Within four years, one half of the people in Europe had died.

The Black Plague still exists today; it will never be eradicated. It lives in animals around the world and can be found in the western and Pacific states of the United States. In the U.S., the plague can be found in ground squirrels and occasionally other rodents: voles, chipmunks, prairie dogs, rats, and mice. Cats and ferrets can get the plague either from fleas or from eating the infected rodents after they die.

People are still sometimes infected with the Black Plague. In the United States, about 10 to 15 people each year contract the disease. In 1925, rats in Los Angeles caused an outbreak of the plague. Globally, about 1,000 to 2,000 people are infected each year. There have been several outbreaks of the Black Plague in India and Africa in the past 20 years.

Those infected with the Black Plague today have better odds of survival. With modern medical treatment, 1% to 15% of those infected die. Without any medical treatment, the death rate spirals to 40% to 60%.

Centuries ago, travelers carried the Black Plague with them to Europe. With today’s global travel a pandemic can spread quickly.

How can we prevent the plague today? According to the Centers for Disease Control, the best public health prevention we can do is to reduce or eliminate flea and rodent infestations. This lowers the risk of people being bitten by fleas where they live, work, and play. When we teach our friends, family members, and coworkers to do the same, we can help prevent or lower the spread of future pandemics.

Getting rid of fleas and rodents isn’t just keeping your home or business clean. It’s a step to protect public health and reduce risk of disease.

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