Can Fleas Transmit Disease?

Fleas can transmit disease, but only in a few cases. While the fleas that infest cats and dogs are primarily the source of tapeworm infections, they can also infect humans. Tapeworms are most often contracted by children who accidentally ingest fleas or come into contact with infected flea feces. The plague is another example of a disease transmitted by fleas, though it is a rare occurrence in the United States.

Fleas that infest humans are more difficult to detect. Adult tapeworms, for example, may lay dormant in the intestine for years without showing any signs of illness. The only way to tell if you have tapeworm is to get a stool sample checked by a doctor.

Researchers have found that fleas carry B. elizabethae, a type of bartonellae that can cause disease in humans. These fleas feed on humans and animals in the wild, including pets and farm animals. Fleas infect both mammals and humans, and they can even infect birds and bats.

The bite of a flea causes an immune response that builds over time. However, unlike a wasp or bee sting, this response takes longer to manifest in humans. The fleas probe for a blood vessel in the body. Once a blood vessel has been found, the flea can lay eggs.