Vacant homes for rent or sale, vacation homes or cottages that are occupied intermittently all can have active flea infestations even though there are no people or pets present. When you don’t know the history of previous occupants, the assumption is that there once were pets staying that house and they left fleas behind.

Another possibility is that wild animals like raccoons, opossums, squirrels and even feral dogs and cats have been nesting in the attic or denning under that house. We say “have been nesting…” because as long as the animals are still present, adult fleas would not likely be attacking people. Usually, it’s only after the animals have died, been evicted, or otherwise moved on, that the flea eggs and larvae they left would develop into adult fleas looking for a new host. Adult fleas that are left without a host can survive for months without feeding.

In trying to track the original source of the fleas, the question may come up: “How long have these fleas been here?” Really hard to say because the flea life cycle is so variable. Fleas have adapted to wait out the bad times when there’s no host animal around, and they can wait for months. Here are the ranges for each stage of the cat flea:

• Eggs hatch 2 to 12 days
• Larvae develop in 7 days to several months
• Pupal development takes 4 to 14 days.
• Adult can remain in the pupal cocoon up to one year without waiting for a host.

If you had all the stages, you can see that the fleas could have come from eggs that dropped off an occupant’s pet just 3 weeks earlier (if conditions are ideal), or they could be from eggs deposited almost a year ago, especially if there have been no occupants since.

To answer “how long,” you also have to consider the environmental conditions in the house and time of year. Has the house been heated? Is the AC on? Humidity is the main factor influencing the length of the flea lifecycle. The shortest development times above area the ideal conditions with humidity levels for larvae of 45-95%. The adult flea’s lifespan increases with higher humidity and lower temperatures. When larval development drags on for weeks, it is usually because conditions are too dry or there is little larval food in the form of adult flea feces.

You may think it will be easier to treat an empty house for fleas, but the down side is that, without pests or their owners present, you don’t know where the “hot spots” area. The hot spots are those places where the pets rest and are consequently the areas where the larvae develop and where adult fleas are waiting in cocoons. If it’s a vacation rental with furniture, it may be easier to find hot spots around sofas and beds. You can also walk the premises and see if you attract more fleas in certain locations.

Adult fleas that are waiting for a host are protected from pesticides inside their cocoons. One strategy is to treat the premise first. Then vacuum, the vibrations and pressure may cause adult fleas to leave their cocoons and come in contact with the products. 

When pests find their way indoors, homeowners are often tempted to try and control the pest problem on their own, but the truth is that most pests are better left to professionals. After all, pest professionals have the knowledge, tools and training to safely and properly eliminate pest infestations. If you have noticed fleas in your home, contact your local pest control professional immediately. Thomas Pest is a family-owned and operated pest management company offering pest control service in Saratoga, Lake George and surrounding areas with third generation experience. If you live in Saratoga, Lake George, or elsewhere in the Capital Region, call Thomas Pest Services at 1.877.518.BUGS (2847), or visit us on Facebook.

Source: Techletter - Volume 30, No. 12