least 2,000 species, including the notorious rat flea and ones that bite cats, dogs, and humans. Because these biting bugs are bloodsuckers, they are known to carry lethal diseases to humans and animals.Some of the earliest historical records mention tiny pests that invaded homes and inflicted bites on man and beast.
They were causing death and disease centuries before microbes were discovered. Perhaps the deadliest recorded flea-born pandemic was the Black Plague in the 14th century.As the population of European countries increased, so did lack of hygiene and proper sanitation.
Human waste and trash were often pitched in the streets, which further contaminated the drinking water. With such muck and mayhem, flea-infested rats were living in.Read more on powerofpositivity.com