Adult fleas are a nuisance to humans and their pets, but can also cause medical problems including flea allergy dermatitis, tapeworms, secondary skin irritations and in some extreme cases, anemia. Although bites are rarely felt it is the resulting irritation caused by the flea salivary secretions that varies among individuals. Some may witness a severe reaction (general rash or inflammation) resulting in secondary infections caused by scratching the irritated skin area. Others may show no reaction or irritation acquired after repeated bites over several weeks or months. Most bites usually found on the ankles and legs may cause pain lasting a few minutes, hours or days depending on one’s sensitivity. The typical reaction to the bite is the formation of a small, hard, red, slightly-raised (swollen) itching spot. There is a single puncture point in the center of each spot. Ants and spiders leave two marks when they bite. Mosquitoes, bees, wasps and bedbugs cause a large swelling or welt.
Fleas may transmit bubonic plague from rodent to rodent and from rodent to humans. Oriental rat fleas can transmit murine typhus (endemic typhus) fever among rats and from rats to humans. Tapeworms normally infest dogs and cats but may appear in children if parts of infested fleas are accidentally consumed.
For successful flea control, infested pets and the premises need to be treated at the same time. People and pets should be out of the house when treatments are done and not return until the treated spray surfaces have dried. Depending on the carpet and type of treatment, it may take several hours. Usually three to four hours to give the insecticide a better chance to work.