Introduction
When our beloved canine companions get fleas, it’s natural to worry that the pests may spread from dog to house.
Fleas are a common parasite that can plague dogs and cats. These tiny, jumping insects feed on the blood of their hosts and can cause severe itching, skin irritation, and discomfort.
While fleas prefer living on animals, they can find their way into homes and potentially bite humans as well. Therefore, it’s important for pet owners to understand how easily fleas can spread from pets into the house and what can be done to prevent infestations.
Life Cycle of Fleas
Fleas go through four life cycle stages: egg, larva, pupa, and adult. Adult female fleas lay eggs on an animal host after feeding on their blood. These small white eggs fall off into the animal’s environment such as their bedding. Flea eggs hatch into larvae within 2-14 days. The larvae feed on organic debris such as dried blood feces from adult fleas for 5-11 days before spinning a cocoon and entering the pupal stage.
Inside the protective cocoon, the flea pupa can remain dormant for weeks to months until environmental conditions are right to emerge as an adult flea. Vibrations, carbon dioxide, heat, and moisture stimulate pupae to emerge. Newly emerged adult fleas jump onto hosts to feed as soon as 24-48 hours after emerging. Once on a host, adult fleas begin feeding on blood immediately. After 1-3 days, female fleas begin laying eggs to continue the flea life cycle.
Under ideal warm and humid conditions, the flea life cycle can be completed in as little as 2-3 weeks. Cooler and drier environments can prolong the flea life cycle to many months or even over a year in extreme cases. This ability for pupae to remain dormant allows fleas to survive through unfavorable conditions and spread disease year-round.
Flea Eggs and Larvae
Flea eggs are laid by adult female fleas. The eggs are small, oval, and pearl-white in color. They are about 0.5 mm in size so are barely visible to the naked eye. Female fleas lay up to 50 eggs per day and can produce hundreds of eggs over their lifetime [1]. Flea eggs fall off the dog and into carpets, furniture, pet bedding and other places in the home that the dog frequents. The eggs hatch in 2-12 days in normal household temperatures. Some may remain dormant for much longer under cool conditions.
When the eggs hatch, small worm-like white larvae emerge that are about 2-5 mm in size [2]. The larvae feed on organic debris and adult flea feces. The larvae avoid light and move deep into carpets and furniture fibers to avoid being detected. Since the larvae depend on the adult flea feces as a food source, just one adult flea can quickly lead to an infestation of hundreds of flea eggs and larvae in a home.
Flea Pupae
The flea pupal stage is critical for the flea life cycle. After the larva spins a protective cocoon, the flea enters the pupa stage. The pupa develops inside the cocoon and can survive for extended periods without a host. According to Facts On Fleas, flea pupae can remain dormant for up to 9 months depending on environmental conditions.
The dormancy of the pupal stage allows fleas to survive without a host until conditions are favorable, then emerge as hungry adult fleas ready to feed. Flea pupae are resistant to insecticides so they can persist in the environment even after treatment. Vacuuming areas regularly where pets frequent can help remove some flea pupae.
Adult Fleas Jump to New Hosts
Contrary to popular belief, adult fleas rarely jump from one host to another. Fleas prefer to stay on the same host for their entire adult life span, which can be up to 100 days. According to FleaScience, “It’s a common misconception that fleas jump on and off their current host, or leave to acquire a new host. Fleas rarely transfer hosts.”
However, adult fleas are capable of jumping off a dog onto people or other pets in close proximity. As Quora notes, “They can jump from one host to another, whether it’s from a dog to a person or vice versa.” The powerful hind legs of fleas allow them to jump up to 8 inches high and 13 inches far.
So while fleas prefer to stay on the same host, they can and will jump onto humans and other pets nearby an infested dog. Their ability to jump makes them adept at spreading to multiple hosts within a home.
Fleas Feed on Blood
Fleas survive by feeding on the blood of their hosts. They use their mouthparts to pierce the skin and suck blood from animals and humans. When fleas bite, they inject saliva into the skin. Flea saliva contains proteins that can cause skin irritation and allergic reactions in some people.
Many people develop mild red bumps and itching after flea bites. However, others experience more severe reactions known as flea allergy dermatitis. This results in larger areas of red, inflamed skin that may ooze or crust over from intense scratching. Anti-itch creams can provide relief, and oral antihistamines may help in severe cases. See a doctor if the rash spreads or you develop signs of infection.
According to the Better Health Channel, “A flea bite is red, swollen and intensely itchy, and secondary infections caused by scratching are common.” The itching and skin irritation occurs as a result of the flea’s saliva. Flea saliva contains proteins that act as anticoagulants to keep blood flowing as the flea feeds. However, these proteins and other substances provoke immune system reactions in humans that cause the itching and inflammation around flea bites (https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/fleas).
Infested Homes
Fleas can infest a home when brought in by pets or other animals. In severe infestations, fleas will spread everywhere. According to the CDC, “Thoroughly clean areas where fleas frequently breed.” Common areas include carpets, rugs, pet bedding, upholstered furniture, and other places where flea eggs and larvae can develop into adults[1]. Another source recommends steam cleaning carpets and rugs before vacuuming to kill adult fleas[2]. Vacuuming should be thorough to remove all stages of the fleas from carpets and floors. It’s also important to launder all fabrics that may be infested, including pet bedding, blankets, pillows, and clothing. Severe home infestations require aggressive cleaning to eliminate all flea life stages.
Preventing Home Infestations
There are several ways you can help prevent fleas from infesting your home:
Vacuum all carpets, rugs, and upholstered furniture frequently to remove flea eggs and larvae. Be sure to empty the vacuum contents in a sealed bag outside after each use. CDC
Wash all pet bedding weekly in hot, soapy water to kill any fleas or eggs. Animal Medical Clinic
Use flea prevention products like collars, spot-on treatments, sprays or powders on your pets. Be sure to treat all pets in the household and follow product instructions closely. Adams Pet Care
Keep grass cut short and bushes trimmed around your home to expose fleas to heat and sunlight.
Inspect pets and yourself for fleas after being outside and treat any infestations quickly.
Treating a Flea Infestation
To fully treat a flea infestation, you need to kill fleas at all stages of their life cycle. This involves using a combination of products and diligent cleaning.
Start by giving your pet a flea bath using a veterinarian-recommended shampoo like Adams Plus Flea & Tick Shampoo to kill adult fleas. Follow up by applying a topical medication like Frontline Plus or Bravecto to kill fleas and continue working for 30 days. Vacuum carpeted areas daily and wash your pet’s bedding to pick up eggs and larvae. Use an insect growth regulator (IGR) like Sentinel Spectrum or Capstar to stop flea eggs and larvae from developing into adults. Spray carpets and furniture with an insecticide containing an IGR as well.
To kill flea eggs that were missed, you may need to repeat this process for 2-3 weeks until the infestation is under control. Be patient and persistent, as it takes diligence to fully clear a flea infestation from your home and pet.
Conclusion
In summary, fleas can definitely spread from dogs into homes through their complex life cycle. Adult fleas live on dogs, cats, and other animals and feed on their blood. The adult females then lay eggs, which fall off into the animal’s bedding, carpets, furniture, and other areas around the home. These eggs hatch into larvae, which develop into pupae surrounded by protective cocoons. The pupae can remain dormant for months waiting for vibrations that indicate a potential host is near. When they sense the vibrations, the pupae emerge as hungry adult fleas that immediately jump onto pets, humans, or other warm-blooded animals. The cycle then continues as the new fleas feed, mate, and lay eggs back in the home environment.
To prevent a flea infestation, it’s essential to use flea control products on your pets year-round. You should also vacuum and wash your pet’s bedding regularly. If you do get fleas in your home, you’ll need to thoroughly vacuum and wash all fabrics, use flea sprays or foggers, and treat your yard. With diligence, you can eliminate fleas and prevent re-infestation by stopping them from completing their life cycle.