It seems that vacuuming kills fleas in all stages of their lives. Researchers at the Ohio State University have determined that vacuuming kills 96 percent of adult fleas and 100 percent younger fleas.
The studies were conducted on the cat flea, or Ctenocephalides felis, the most common type of flea plaguing companion animals and humans.
Researchers also tested vacuum bags for toxicity and exposed fleas to churning air in separate tests to further explore potential causes of flea death.
They believed that the damaging effects of the brushes, fans and powerful air currents in vacuum cleaners combine to kill the fleas. The study used a single model of an upright vacuum, but researchers don't think the vacuum design has much bearing on the results.
"No matter what vacuum a flea gets sucked into, it's probably a one-way trip," said Glen Needham, associate professor of entomology at Ohio State and a co-author of the study.
Researchers theorized that the vacuum brushes wear away the cuticle, a waxy outer later on fleas and most insects that allows the bugs to stay hydrated. Without the waxy protection, the adult fleas, larvae and pupae probably dry up and die, he said.
"We didn't do a post-mortem, so we don't know for sure. But it appears that the physical abuse they took caused them to perish," he said.
Six tests of vacuuming the adult fleas yielded an average of 96 percent of fleas killed; three tests of vacuumed pupae and one test of vacuumed larvae (in their third stage of development) resulted in 100 percent killed.
Conventional wisdom has suggested for years that homeowners should vacuum carpeted areas to physically remove fleas, and some recommendations went so far as to say the contents of the bags should be emptied, burned or frozen.
The lead author of the study, W. Fred Hink, professor emeritus of entomology at Ohio State sought to test the effects of vacuuming on all flea life stages and whether any extra disposal steps or additional chemical controls are necessary.
Fleas have multiple life stages. Adult fleas eat blood meals and mate while living on a host animal. Females lay eggs, which roll off of the animal and onto the floor, furniture or pet bedding. After hatching from the eggs two to 14 days later, the insects go through three larval stages, the last of which spins a cocoon to protect the pupa stage. New adults typically emerge within a week or two.
The study involved groups of 100 adult fleas at a time, as well as groups of 50 pupae and 50 larvae, by vacuuming them up from a tightly woven kitchen-type of carpet. Six tests of vacuuming the adult fleas yielded an average of 96 percent of fleas killed; three tests of vacuumed pupae and one test of vacuumed larvae (in their third stage of development) resulted in 100 percent killed.
In comparison, an average of only 5 percent of adult fleas died after being held in paper vacuum bags to test for toxicity, and an average of only 3 percent died when circulated in moving air.
Needham said: Vacuuming is a great strategy because it involves no chemicals and physically removes the problem."
The results are published in the issue of the journal Entomologia Experimentalis et Applicata.