Fleas & Parasites

Fleas are one of the most common ectoparasites of companion animals and feed on the blood of their hosts. The blood intake of a female flea can be equivalent to more than 15 times its body weight. Well fed this way, adults survive on a host for up to 140 days. Several thousands of eggs are laid by female fleas and dropped wherever the host animal goes. The warm temperature and humidity in homes provide a favorable microclimate for multiple flea life cycles.

Flea species

Fleas belong to the insect family (classification: phylum Arthropoda, class Insecta). In most parts of the world, only a limited number of flea species are common on companion animals, particularly on cats and dogs. These are

• Ctenocephalides felis, the cat flea,
• Ctenocephalides canis, the dog flea,
• Archaeopsylla erinacei, the hedgehog flea,
• Pulex irritans, the human flea, and
• Echidnophaga gallinacea as well as Ceratophyllus gallinae, fleas found on poultry.

The flea life cycle

All flea species develop similarly via four stages:

Eggs: are laid 24 to 36 hours after first blood meal.

Larvae: three larval stages, life span 5 to 12 days.

Pupae: best protected and resistant life stage.

Preemergent adults: The waiting stage, emergence of adults upon stimuli (pressure, heat).

​The life cycle of the flea is based on holometabolic metamorphosis. It can be completed in as little as 14 days or be prolonged up to 140 days, depending mainly on temperature and humidity.

Harmful effects of flea infestation

Flea infestation can disrupt the general well-being of all animals, cause itching, redness, hair loss, and in certain cases severe skin infections. The most harmful effects are:

• Blood loss
• Flea allergy dermatitis (FAD)
• Transmission of tapeworms
• Transmission of bacterial diseases​

Roundworms

Roundworms are a common intestinal parasite in dogs.

• Puppies may be infected in utero (before birth) as worms cross the placenta from the mother to the puppy. These puppies are born already infected with roundworms.
• Puppies can become infected after they are born by ingesting infected milk or by consuming parasite eggs from the environment.
• Dogs can also be infected by roundworms when they eat mice or other infected mammals.

How will roundworms affect a dog?

Adult roundworms live in the infected dog’s intestines. Many dogs do not show symptoms of infection. However, dogs with heavy roundworm infections, especially puppies, can have symptoms such as:

• Weight loss
• Dull hair
• Potbellied appearance

The dog may cough as the migrating roundworms move through the lungs.

Adult roundworms may be seen in a dog’s feces or vomit. They will appear white or light brown in colour and may be several inches long.

Tapeworms

Tapeworms are long, flat worms that attach themselves to the intestines of a dog or cat.

• A tapeworm body consists of multiple parts, or segments, each with its own reproductive organs.
• Tapeworm infections are usually diagnosed by finding segments—which appear as small white worms that may look like grains of rice or seeds—on the rear end of a pet, in its feces or where a pet lives and sleeps.
• There are several different species of tapeworms that may infect a dog or cat, each with stage(s) in a different intermediate (in-between) host, which the pet eats. Some use fleas as the intermediate host; others use small rodents, such as mice and squirrels, as intermediate hosts.

How will tapeworms affect a dog?

Dogs with tapeworm infections may not appear to be sick and may not even lose weight as a result of the infection. However, a large number of tapeworms may cause illness such as diarrhea.

​Roundworms

Roundworms are a common intestinal parasite of cats. Cats are most often infected as kittens. Roundworms may be contracted in different ways, making them easy to spread and hard to control.

A cat may take in (ingest) infective roundworm eggs from its environment or by eating mice or other small animals. Infection in kittens may occur through the mother’s milk.

How will roundworms affect a cat?

Adult roundworms live in the infected cat’s intestines. Most cats will not have symptoms of infection. However, cats with major roundworm infections may show:

• Weight loss
• Dull hair
• Potbellied appearance

The cat may cough as the migrating roundworms move through the lungs.

Adult roundworms may be seen in a cat’s feces or vomit. They will appear white or light brown in color and may be several inches long.

Tapeworms

Tapeworms are long, flat worms that attach themselves to the intestines of a cat. A tapeworm body consists of multiple parts, or segments, each with its own reproductive organs.

• Tapeworm infections are usually diagnosed by finding segments—which appear as small white worms that may look like grains of rice or seeds—on the rear end of a pet, in its feces or where a pet lives and sleeps.
• There are several different species of tapeworms that may infect a cat, each with stage(s) in a different intermediate (in-between) host, which the pet eats.
• Some use fleas as the intermediate host; others use small rodents, such as mice and squirrels, as intermediate hosts.

How will tapeworms affect a cat?

Cats rarely show any symptoms associated with tapeworm infection. Occasionally, tapeworms may cause illness such as diarrhea or weight loss.

Ticks are fairly common ectoparasites of dogs in tick-prevalent geographies. How often you see ticks on a dog and how severe a tick infestation will be depends on the region of the country in which you live, the time of year (tick activity varies in warm and cool weather), and the lifestyle of the dog. Even dogs that only spend brief periods of time outside can pick up ticks.

How will ticks affect your dog?

Ticks attach to a dog by inserting their mouth parts into the dog’s skin. Many ticks also produce a cement-like substance that helps them to remain attached. After attaching to a dog, ticks begin feeding on the dog’s blood. The places where ticks attach can become red and irritated.

Although rare, ticks could consume enough of a dog’s blood to cause a deficiency called anemia. Certain ticks can also cause a rare paralysis in dogs.

Ticks are capable of transmitting many diseases to dogs such as:

• Lyme disease, the disease more people are familiar with. Lyme disease can cause arthritis and swelling of a dog’s joints, resulting in painful lameness.
• Rocky Mountain spotted fever can cause fever, loss of appetite and other signs. There are also other diseases that ticks can transmit to a dog. Your veterinarian can answer questions about the diseases that are of concern where you live.

To learn more about the best treatment for ticks in your area, talk to your veterinarian.