Fleas (Order: Siphonaptera) are small, flightless insects known for their parasitic relationship with mammals and birds. Despite their tiny size, these pests can cause significant discomfort and health issues for their hosts. Fleas are notorious for their jumping abilities, allowing them to move quickly from one host to another, making them difficult to control.

How to Identify Fleas

Fleas are tiny, wingless insects measuring about 1/8 inch in length. Their bodies are laterally compressed, allowing them to move easily through the fur, hair, or feathers of their hosts. Fleas have long, powerful legs adapted for jumping, with some species capable of leaping up to 150 times their own body length. They are usually reddish-brown to black in color and have piercing-sucking mouthparts designed to feed on the blood of their hosts.

Types of Fleas in Pennsylvania, New Jersey and Delaware

Dog Flea

(Ctenocephalides canis)
The dog flea is one of the most common flea species found on domestic dogs. They can also infest cats, humans and other animals. Dog fleas are known for their ability to transmit tapeworms to their hosts.

Cat Flea

(Ctenocephalides felis)
Cat fleas are the most prevalent flea species in the United States, affecting both cats and dogs. These fleas are known carriers of several diseases, including cat scratch fever and tapeworms.

Human Flea

(Pulex irritans)
As the name suggests, human fleas prefer to feed on human blood, but they can also be found on pigs, dogs and other animals. They are less common than cat and dog fleas but can cause severe irritation and discomfort.

Sticktight Flea

(Echidnophaga gallinacea)
Sticktight fleas are known for their tendency to attach firmly to their hosts, often around the eyes and ears. They primarily infest poultry but can also affect other animals, including dogs and cats.

Sand Flea

(Tunga penetrans)
Sand fleas, also known as jiggers, burrow into the skin of their hosts, causing painful lesions. They are typically found in sandy areas and can affect humans, dogs and other animals.

Signs of an Infestation

Detecting a flea infestation early is crucial for effective control. Here are some common signs of a flea infestation:

  • Frequent Scratching: Pets, particularly dogs and cats, scratching more than usual.
  • Red Bumps and Flea Dirt: Tiny red bumps and black specks (flea dirt) on your pet’s skin or in their bedding.
  • Visible Fleas: Adult fleas can sometimes be seen on your pet’s fur or in areas where they rest.
  • Hair Loss and Skin Irritation: Severe infestations can lead to hair loss and irritated, inflamed skin due to constant scratching and biting.

Health and Damage Considerations

Fleas can cause various health issues for both pets and humans. These include:

  • Allergic Reactions: Some pets develop flea allergy dermatitis, a hypersensitive reaction to flea saliva that causes severe itching and discomfort.
  • Anemia: In severe infestations, the loss of blood can lead to anemia, particularly in young or small animals.
  • Disease Transmission: Fleas are carriers of several diseases, including murine typhus, bartonellosis (cat scratch fever) and tapeworms.

Behavior

Fleas are highly adapted for survival and reproduction. They spend most of their lifecycle off their host, laying eggs in the environment. The eggs hatch into larvae, which feed on organic debris before pupating and emerging as adults. Fleas are attracted to warmth, movement and carbon dioxide, which help them locate a suitable host.

Habitat

Fleas thrive in warm, humid environments. Outdoors, they can be found in shaded, moist areas such as under leaves, grass and shrubs. Indoors, they prefer to hide in carpets, pet bedding and upholstery. Flea infestations can persist year-round in homes with central heating.

Lifecycle

The flea lifecycle consists of four stages: egg, larva, pupa, and adult. 

  • Egg: Flea eggs are laid on the host but often fall off into the environment. They hatch within a few days.
  • Larvae: Flea larvae feed on organic matter, including flea dirt, and develop in protected environments like carpets and soil.
  • Pupae: After spinning a cocoon, the larvae transform into pupae. This stage can last for several weeks to months, depending on environmental conditions.
  • Adults: Adult fleas emerge from the pupae when they detect a potential host nearby. They begin feeding and mating immediately.

Feeding

Fleas are obligate blood feeders, meaning they must consume blood to survive and reproduce. Adult fleas feed on the blood of their host, typically several times a day. Flea larvae, however, do not feed on blood. Instead, they consume organic debris, including the dried blood excreted by adult fleas.