Fleas, a common parasite – By: Dr. Cindy Krane
Fleas, a common parasite – By: Dr. Cindy Krane
Date: May 1, 2012By definition a parasite feeds on its host and causes harm to its host. Fleas are the most common external parasite of cats and dogs. They are tiny, dark brown, wingless, blood sucking insects. They are a major nuisance to our pets and vectors of disease.
There are over 2000 different species of fleas, the peskiest of which is (Ctenocephalides felis) the cat flea. Equipped with piercing mouth parts designed to suck blood from their victims, little spinney combed limbs to hold onto their victims, and legs so powerful can almost fly from victim to victim. They are excellent athletes and can jump ~ 10 inches; equivalent to 200 times the body length or a long jumper in the Olympics jumping 1200 feet.
Fleas lead a very simple life with only two goals in mind. The first is to eat and the second is to reproduce. Their favorite restaurant and boudoir is your pet! They have a simple 4 stage life cycle; adult, egg, larvae, and pupa. Once an adult flea finds its way onto your pet its mouthpart pierces through the skin, secretes saliva laden with anti-coagulants so the blood can flow freely from your pet into the flea. Immediately after having a blood meal the female flea lays up to 40 tiny white eggs on your pets’ coat. They eggs drop off of the pet and land up in the pets’ environment. When the egg drops off so does some of the “flea dirt “(flea dirt is a nice way of describing the fleas feces which is actually blood that was sucked from you pet then freshly excreted from the fleas digestive tract). When the eggs hatch into larvae the flea dirt (looks like flecks of pepper) along with dried dead skin serves as their food source. Larvae are little caterpillar like bugs that graze around your carpets, furniture and pets’ bedding feeding on flea dirt and dead skin. The larvae molt a few times then spin a cocoon in which they develop into pupa. At this stage the flea can arrest / halt its development and lie dormant for months. The cocoon is very resistant to insecticides and freezing temperatures and will protect they pupa until they feel safe and sense that the environment is favorable for hatching and for survival of adult fleas. Stimulated by vibrations, movement, warmth, humidity and CO2 levels the pupa emerge from their cocoon. The adult fleas can survive for 1-2 weeks before they need to locate a host (your pet) and start feeding (on your pets’ blood). This completes the life cycle of the Ctenocephalides felis. The fleas unique ability to prolong the cocoon phase until a suitable host explains why when people come back from vacation they find a flea infestation. People are under the false believe that the fleas came home from the kennel with their pet but in reality the fleas were waiting patiently at home for a pet / person to return home and offer up a fresh meal.
The parasitic relationship between the flea and the host exposes your pets and family members to a variety of disease and illness. They carry and act as a vector for viruses, parasites and bacteria. An infestation of fleas, especially on a young, thin, debilitated or elderly patient can result in severe, life threatening anemia. Tapeworms, dipylidium caninum, which are carried by fleas, live in the pets small intestines; compete for nutrition and causes perianal irritation.
Fleas carry zoonotic disease (diseases that are transmitted from animals to people). Fleas transmit an organism called bartonella henselae to cats. Cats in turn transmit the organism to people via a bite / scratch causing Cat Scratch Fever; and infectious disease characterized by high fevers and swollen painful lymph nodes. Fleas carrying the organism yersinia pestis transmitted the bubonic plaque causing “black death” wiping out 25% of Europe’s population in the Middle Ages.
Fleas carry zoonotic disease (diseases that are transmitted from animals to people). Fleas transmit an organism called bartonella henselae to cats. Cats in turn transmit the organism to people via a bite / scratch causing Cat Scratch Fever; and infectious disease characterized by high fevers and swollen painful lymph nodes. Fleas carrying the organism yersinia pestis transmitted the bubonic plaque causing “black death” wiping out 25% of Europe’s population in the Middle Ages.
Additionally fleas cause a variety of skin ailments including flea allergy dermatitis (FAD), flea bite hypersensitivity (FBH), and hot spots. In cases of FAD/ FBH the fleas’ saliva contains histamine like compound that irritates the skin. They may be a genetic breed predilection as it is very common in atopic breeds. Most commonly affects adult cats/ dogs ~ 3-6 years of age living in warm, humid climates, without seasonal or sex predilection. The pet develops an almost compulsive biting / corncob nibbling on its coat and skin concentrating on the back ½ of its body, back of the thighs, lower abdomen and inguinal region. The diagnosis is made by finding live fleas and / or flea dirt on the skin. Tapeworm segments may be found on the rectum or in the stool or a blood test may help make the diagnosis definitive.
The intensity of the allergic reaction does not correlate with the number of fleas. Many per owners are thus skeptical of this diagnosis because they can not visually appreciate a infestation of fleas. Further more many people are in denial that they beloved Fluffy who’s paws never touch the ground and who lives in there immaculate house could have parasites.
The intensity of the allergic reaction does not correlate with the number of fleas. Many per owners are thus skeptical of this diagnosis because they can not visually appreciate a infestation of fleas. Further more many people are in denial that they beloved Fluffy who’s paws never touch the ground and who lives in there immaculate house could have parasites.
Treatment of FBH/FAD is centered around relieving inflammation. Corticosteroids / antihistamines are prescribed to decrease the itching. Antibiotics may be indicated for secondary bacterial infections due to self trauma, over grooming and hot spot. This is symptomatic care and will bring relief to the pet but does not address the underlying problem; the flea itself. Aggressive flea control must be implemented on multiple levels.
Fleas are highly adaptive and resistant to many of our insecticidal products. Their life cycle must be challenged at multiple stages of development. An integrated flea control to kill adult fleas AND prevent reproduction is essential. Adult fleas represent only 1-5% of the total flea population; they are just the tip of the iceberg. Adulticides like Frontline top spot, PetArmour, and Advantage, target this portion of the population.
IGR insect growth regulators are of equal if not greater importance as they can break the cycle, arresting the development of eggs, larva and pupa into adult fleas.
Examples include Sentinel and Program, Biospot, Frontline Plus. The numerous products available both by prescription and OTC are beyond the scope of this article. It is important however to note that although most products are safe many are contraindicated in puppies less than 12 weeks of age, older, debilitated patients or cats and kittens.
The carpeting must be vacuumed, the floors swept and mopped, and the bedding washed frequently to decrease the likelihood of re-infestation. The rest of the house and yard can be treated by the home owner with foggers, premise spray, or inert substances like boric acid. Alternatively you may want to employ a professional exterminator to use stronger chemicals and guarantee the outcome. In any cause be sure your arsenal against fleas is multi-modal; they are resistant pests.
Examples include Sentinel and Program, Biospot, Frontline Plus. The numerous products available both by prescription and OTC are beyond the scope of this article. It is important however to note that although most products are safe many are contraindicated in puppies less than 12 weeks of age, older, debilitated patients or cats and kittens.
The carpeting must be vacuumed, the floors swept and mopped, and the bedding washed frequently to decrease the likelihood of re-infestation. The rest of the house and yard can be treated by the home owner with foggers, premise spray, or inert substances like boric acid. Alternatively you may want to employ a professional exterminator to use stronger chemicals and guarantee the outcome. In any cause be sure your arsenal against fleas is multi-modal; they are resistant pests.
