Flea bites produce severe reactions in some individuals while hardly affecting others. Most bites occur on the lower legs and ankles and often are irritating or sore for several days. Historically, fleas were involved in the greatest epidemic of human disease, the Bubonic Plague, ever known to man. The flea transmitted the plague organism from diseased rats to man. A different type of problem caused by fleas is their ability to serve as intermediate hosts of the dog tapeworm.
Children pick up the tapeworms when they accidentally ingest infected fleas.
The female flea must have a blood meal in order to lay fertile eggs. She will usually lay 4-8 eggs following each blood meal and may lay several hundred eggs over her lifetime. The small whitish round eggs are usually loosely attached to the hair of a dog or cat. The eggs are brushed or fall from the body of the animal to the floor where they lodge in carpets, cracks in the floor, etc. The eggs hatch in about 10 days into small, whitish worm-like larvae.