6. Fleas and Flea Bite Hypersensitivity

What is the most common flea in dogs and cats? (need to know this)

Ctenocephalides felis (cat flea: mustache and mullet flea)

What is the scientific name of the dog flea?

Ctenocephalides canis

What is the scientific name of the Poultry flea, face flea, stick tight

flea?

Echidnophaga gallinacea

What is the scientific name of the human flea?

Pulex sp.

What are the general stages of the flea life cycle?

• Egg

• Larvae - 3 molts

• Pupae

• Adult

T/F The flea can transform into an adult within weeks to months

True

How would you describe the egg from a flea?

• Pearly white, oval,

rounded ends

• 0.5 mm long

Where is the flea egg deposited?

haircoat

How long does it take for the eggs to hatch?

1-6 days

Describe the larvae (L1-L3) of the flea

• Slender, white, segmented

• Free-living

What does the flea larvae food on?

organic debris and flea feces

How do you desiccate (kill off) the flea larvae?

sunlight and low humidity (

How long does the flea larvae survive in the environment?

5-11 days, up to 3 weeks

How would you describe the pupae?

• Silk-like cocoon

• Ovoid, 0.5 mm long, white

Where will you find the pupae?

Soil, vegetation, carpets, bedding, under furniture

How long does it take the pupae to mature into an adult? What is the stage called?

- 1-2 weeks to mature to adult

- Pre-emergent adult (dormant stage - 350 days)

What are some of the hatching stimulators for the pupae?

Physical pressure, CO2, substrate movement,

heat, changes light patterns

How long can the adult flea survive without feeding?

12 days

T/F The adult flea feed immediately if host nearby

True

When does the female start producing eggs after a meal?

24-48hrs (40-50 eggs)

How long does it take for the flea to complete its lifecycle in the typical household conditions?

3-8 weeks

All life-stages die at what temperature?

37°F

T/F The flea can survive on pets and wildlife for the winter

True

What stage can the flea survive the winter in?

pre-emergent (pupae) adults

What non infectious disease can fleas cause in young animals that have a heavy infection?

Iron-deficiency anemia

What are the THREE zoonotic diseases associated with?

- Rickettsial diseases

- Cat scratch disease (Bartonella henselae)

-Plague (Yersinia pestis)

What worm is associated fleas?

Tapeworms (Dipylidium caninum)

What is the MOST common pruritic skin disease?

Flea bite allergy?

What is the pathogenesis of flea bite allergy?

Flea feeds -> salivary proteins released into skin of host -> Sensitization occurs-> hypersensitivity develops

What are the TWO types of hypersensitivities develops with flea bite allergy?

Type I and IV

What cellular response can be seen with flea bite?

Cutaneous basophil response

T/F There is no breed, sex, age predilection to flea bite allergy

True

What type of animals are predisposed to flea bite allergy?

Atopic dogs/cats

If a patient comes in and you suspect flea bite allergy, what clinical sign can be a sign that directly point you to this suspicion?

pruritus in the back half

Where will the clinical signs manifest in the dog for flea bite?

Caudal dorsum

Where will the clinical signs manifest in the cat for flea bite?

Caudal dorsum and neck

What are some of the clinical signs also associated with flea bite allergy in dogs?

• Papules, crusts

• Excoriations

• Pyotraumatic dermatitis (hot spot)

What are the THREE signs that the flea bite allergy is chronic?

Alopecia, lichenification, hyperpigmentation

What are the clinical signs of cats with flea bite allergy?

• Same as dogs

• Miliary dermatitis

• Symmetric alopecia w/o lesions

• Eosinophilic granuloma complex

Read or type if youre a try hard:

what are some of the DDX for flea bite allergy?

Differential Diagnoses

• Other allergies

• Atopy, food allergy

• Infections

• Bacteria, Malassezia

• +/- Dermatophyte

• Other parasites

• Sarcoptes sp.

• Cheyletiella sp.

• Biting/sucking lice

• +/- Demodex

• Endocrinopathy (hypoT4, Cushing's)

• Adverse drug reaction

• Neoplasia

• Epitheliotropic lymphoma

How many bites from a flea does it take to elicit a response?

1

What causes the allergic reaction?

the saliva

What may you find on physical exam of a suspected flea bite allergy patient?

• Fleas

• Flea feces (wet paper towel test)

• Dermatologic findings

T/F Some helpful clues when positive Intradermal and serologic tests but false positives are possible

True

How do you treat flea bite allergy?

Avoidance

• Flea control

• Animals - repellents

• Environment

• Anti-inflammatory medications

• Anti-microbial medications

• Hyposensitization: not effective

• Irritant reactions

What is in alot of the repellants and is very bad for the kitty?

pyretherin

How can you control the environment with fleas?

• Adulticide

• Insect growth regulator (IGR)

• Professional exterminators

• Boric acid (dessicant)

• Vacuum weekly

• Wash bedding

• Clean up yard!

What is the most effective adulticide?

sprays

If you have an antichemical person, what can you give them that kills the flea larvae in grass and soil?

Sterile nematodes (Steinerema carpocapsae)

Read:

Flea control formulation

• Collars

• OTC - not reliable

• Spot-on treatments (long- acting)

• OTC - not reliable

• Oral

• Injectable

• Dips

• Sprays

• Shampoos

• Powders/foams

What is the MOA of Organophosphates?

Irreversibly bind ACh esterase

What animal is the Organophosphates toxic to?

cats

What is the other Cholinesterase inhibitors that is safer than Organophosphates because it reversibly binds Ach?

Carbamates

What drug class irreversibly bind ACh receptor causing overactivation and is resistant to ACh esterase?

Neonicotinoids

What drug class binds and interfere with the GABA and glutamate-gated

chloride channels?

Ligand- gated ion channels

What flea control is a natural extract from Chrysanthemum flower?

Pyrethrins

What is the MOA of Pyrethrins?

Causes extended membrane polarization - modulates Na channels

What is Pyrethrins inactivated by?

UV light

T/F Pyrethrins rapid kill adult and larvae and also: ticks, lice, Cheyletiella,

Otodectes

True

What is the Synthetic pyrethrin that is more stable to UV light and has a faster kill?

Pyrethroid

What animal is Pyrethroid toxic to?

CATS (Frequently in OTC dog flea/tick products will see toxicity in cats!)

What flea control uses Juvenile hormone analogs and is Ovicidal, Larvicidal and has long residual activity?

Insect Growth Regulators

T/F Insect Growth Regulators is an adulticide

Fasle is not

What is the MOA for Lufenuron?

chitin synthase inhibitor (Insect development inhibitor)

What are the restrictions of Lufenuron?

>2 lb, >4 weeks old

What is the spectrum that Imidacloprid (neonicotinoid) covers?

• Adult fleas, eggs, larvae

What brand that includes Imidacloprid (neonicotinoid) should you not give to cats?

Advantix

All Imidacloprid (neonicotinoid) are monthly spot-ons except Seresto® collar. How long SHOULD the collar last?

8 months

What is the MOA for Fipronil?

GABA receptor antagonist (ligand-gated ion channel)

Where does Fipronil concentrate at?

sebaceous glands

What is the spectrum of Fipronil?

Fleas, ticks, lice, flies

What is firponil approved for?

Approved for dogs and cats >8 weeks

What is the MOA of Selamectin (avermectin)?

glutamate-gated Cl channel activator (ligand-gated ion channel)

How often do you have to apply Selamectin (avermectin) and is it slow or fast kill?

once monthly, slow

What are the age restrictions in the Selamectin?

Dogs > 6wks age, cats >8 wks age

What is the MOA of Dinetofuran?

neonicotinoid

What is the spectrum for Dinetofuran?

Fleas, eggs, larvae

What is the age for Dinetofuran?

Dogs and cats >8 wks

T/F Dinetofuran is a slow kill

False, rapid

Spinetorum is a neonicotinoid and ligand-gated ion channel blocker, what spectrum of fleas does it kill?

adult fleas

T/F Spinetorum has one size only in cats only >8 wks

True

Indoxacarb is a ligand-gated ion channel blocker. What is the spectrum that flea does this cover?

adult fleas, larva

What requires bioactivation by insect gut enzymes leading to paralysis

(paralyzes mouthparts of flea - prevents bite)?

Proinsecticide

T/F Indoxacarb is a Proinsecticide

True

Capstar, or Nitenpyram, kills what spectrum of flea?

adult flea only (+ maggots)

What is the neonicotinoid, that is fast kill and kills adult fleas ONLY?

Spinosad

What drug can you not administer spinosad with high does of because it will call

ivermectin

What is the name of the isoxazoline (ligand-gated ion channel blocker), that kills adult fleas, ticks, Demodex, Sarcoptes, Otodectes, lice, biting flies, Cheyletiella and comes as a once monthly oral chew?

Afoxolaner (NEXGARD)

T/F A side effect of Afoxolaner is vomiting

True

If Afoxolaner is artifically beef flavored, is it okay for a food trial?

yes apparently

What isoxazoline is for DOGS ONLY in a oral chew, has a topical for dogs and cats (>6 months) and can be given once every 3 months?

Fluralaner (bravecto)

Bravecto®PLUS covers what parasites in cats? (5)

heartworm, roundworm, hookworm, tick, flea

If a patient throws up bravecto, what should you do?

redose if within 3 hrs oral tabs

What isoxazoline is an oral tablet in dogs (>6 mo) that is pork flavored and is not for food trial? The "trio" version of it contains pyrantel and moxidectin; 8 wks age; flea, tick, heartworm, roundworm, hookworm.

Sarolaner (simperica, simparica trio)

What isoxazoline can be given as a oral tablet dogs and cats (8 weeks age, 2 kg) that is beef flavored and given once monthly but has HELLA side effects?

Lotilaner (credillio)

What are the side effects of credillio?

diarrhea, weight loss, polyuria, elevated BUN