The Black Death (1347–1351) was the most infamous pandemic caused by fleas, which transmitted the Yersinia pestis bacteria. These fleas, often carried by rodents or in clothing, spread the bubonic plague, killing approximately 25–50 million people, or over a third of Europe's population.
Bubonic plague is an infection spread mostly to humans by infected fleas that travel on rodents. Called the Black Death, it killed millions of Europeans during the Middle Ages.
The Black Death (Bubonic Plague) in the mid-14th century killed an estimated 30-50% (or up to 75-200 million people) across Eurasia and North Africa, wiping out a massive portion of Europe's population, though figures vary, with some regions hit harder than others, leading to significant societal shifts.
Key points. The bacterium that causes plague, Yersinia pestis, is transmitted by fleas and cycles naturally among wild rodents. People usually get plague after being bitten by an infected rodent flea or by handling an infected animal. People can also become infected through exposure to sick pets, especially cats.
The bacteria that cause the plague, Yersinia pestis, are most often transmitted by the bite of fleas that have acquired the bacteria from infected squirrels, chipmunks, and other wild rodents, officials said. Symptoms typically show within two weeks of exposure to an infected animal or flea.
Fleas are small insects that survive by feeding on animal or human blood. Their bites can cause discomfort, itchiness, and irritation. Sometimes, fleas can infect people or pets with the germs that cause flea-borne typhus, plague, or cat scratch disease.
To kill fleas instantly, use fast-acting oral medication like Nitenpyram (e.g., Capstar) for immediate knockdown on pets, or give your pet a warm bath with mild soap/flea shampoo and use a flea comb to physically remove them, dunking fleas in soapy water to drown them. For home treatment, vacuuming and using insecticides with growth regulators help, but remember you'll need ongoing preventatives to break the flea life cycle.
In North America plague mostly affects rodent populations such as chipmunks, ground squirrels, and prairie dogs. These rodent populations serve as the primary reservoir for the disease. Plague can also affect other mammals, such as carnivores and scavengers that feed on rodents.
Did anyone survive the Black plague if they got it?
Up to half of people died when the Black Death swept through Europe in the mid-1300s. A pioneering study analysing the DNA of centuries-old skeletons found mutations that helped people survive the plague. But those same mutations are linked to auto-immune diseases afflicting people today.
There have been no deaths from plague in 2025. Plague is a bacterial disease of rodents and is generally transmitted to humans through the bites of infected fleas but can also be transmitted by direct contact with infected animals, including rodents, wildlife and pets.
The mass extermination of the continent's felines is considered an indirect cause of the Bubonic plague spread by fleas on rats, which would otherwise have been hunted by the dead cats.
Plague is an illness you get from Yersinia pestis bacteria. It can infect your lymph nodes (bubonic), blood (septicemic), lungs (pneumonic) or throat (pharyngeal). It most commonly spreads through flea bites. Plague caused deadly outbreaks in the past and still exists in many countries today.
Severe disease is most often seen in wild rodents like prairie dogs, chipmunks, and squirrels. Less often, it surfaces in wild rabbits (especially cottontails), pet cats, and, rarely, people. Although pet dogs also can catch plague or plague-carrying fleas, they are more resistant to getting sick.
Such a deadly disease may have selected for genetic variants that protected against infection. People with protective versions of certain genes would be more likely to survive and pass on those variants to future generations.
It didn't stop the spread of the plague. Unfortunately, that's a romantic spin on the truth; the fire only burned about a quarter of urban London, so wouldn't have removed the plague completely and records show people continued to die from the plague after the 1666.
The disease is now vanishingly rare in both the US and Europe, largely thanks to changes in lifestyles that prevent it from spreading to humans from infected fleas as easily. Even when it does occur, it can be relatively easily treated with antibiotics, saving lives.
– what smells do fleas absolutely hate? Due to their sensitive sensory systems, certain natural scents like lavender, eucalyptus, and citronella are extremely off-putting to fleas. These scents not only repel adult fleas but can also disrupt their ability to detect a host, effectively breaking the cycle of infestation.
No, fleas cannot establish permanent colonies in human hair. They prefer animal fur and typically jump off humans within 24 hours. Human hair lacks the density and warmth that fleas need for reproduction and long-term survival.
Fleas can carry a plethora of harmful pathogens, including tapeworms and Bartonella (the bacteria responsible for cat scratch fever). Severe flea infestations that are left untreated can cause anemia, especially in young or debilitated pets, due to the loss of blood from repeated feeding.
Fleas found on dogs originate from rodents, birds, insectivores and from other Carnivora. Dogs therefore may serve as ideal bridging hosts for the introduction of flea-borne diseases from nature to home.
