But rats and mice can also be sources of fleas or causes of continuing infestation. However, fleas can survive in homes where there are only humans. It is a fact that some humans are resistant to or immune to flea bites. That is, they can live with the fleas and not be aware that pests are present. But most people are very sensitive to flea bites.
Flea bites are most likely to be found on the legs of people in flea infested areas.
The bites have a red halo around a small red spot, and they may swell. Recently, there have been comments about fleas becoming resistant to some of the insecticides used to control them. This may be true to some extent, but in heavy infestations, it is more likely that something is being omitted in their control. It could be that an insecticide is not being used correctly, the life cycle is not being considered, or another source has escaped notice. When an infestation seems uncontrollable in the summer, there is usually sandy soil or a gravel driveway around the home.