According to the Illinois Department of Public Health, humans are able to contract bubonic plague and murine typhus from the bites of infected fleas. However, most flea bites just cause bumps that are red, itchy and often in groups of three, MedlinePlus indicates.
IDPH explains that fleas spread bubonic plague worldwide. Infected fleas typically live on wild rodents. Outdoor pets, especially cats, occasionally transport contaminated fleas, as well. Humans are at risk of flea bites when they come in contact with the flea carriers. This disease is curable with a quick antibiotic treatment.
Murine typhus is usually found in rat-infested locations within tropical regions, IDPH continues. To develop the disease, humans must be in close contact with the rats carrying the fleas. Antibiotics are also used to treat this infection.