Flea allergy Flashcards
What are fleas?
- Small, brown, wingless bloodsucking insects
Flea order
- Siphonaptera
What is the major flea of cats and dogs?
- Ctenocephalides felis felis
What are the two main fleas that affect dogs and cats?
- Ctenocephalides felis felis (#1)
- Echidnophaga gallinacean (Poultry sticktight flea)
C. canis
- Probably extinct in the US
What is the flea of humans and medium sized mammals (fox, possum, raccoon, etc.)?
- Pulex irritans
Where is the sticktight flea (Echidnophaga gallinacean) found?
SE US and Florida
What is the life cycle of C. felis fleas (basic)?
- Eggs –> 3 larval stages –> pupa –> adult
How long does the entire life cycle take for C. felis?
- 3-4 weeks
- Can be completed in as little as 12-14 days
- Can take up to 50 weeks
Where do fleas come from?
- Fleas outdoors come from eggs deposited from flea infested feral dogs and cats and urban wildlife**
- Eggs deposited can develop into adults (eggs - larvae - pupae - adults)
- As pets are let outside, newly emerging fleas jump on pets
- Or fleas jump on people and are transported back into homes
What does C. felis development require?
- Warm temperature and humidity >50%
- Times vary depending on temp and humidity
Where are eggs laid?
- Laid on the host and FLL OF ONTO THE ENVIRONMENT
How do flea eggs handle freezing or low humidity?
- They don’t (they die)
Flea eggs - how long to hatch
Usually around 2-10 days
- May go dormant and fall and not hatch for 3-4 months
What do larva feed on?
- Feed on organic debris and flea feces
- Blood (adult flea feces) is an important component
- Larvae feed on a variety of organic debris incluign flea egg shells and other flea larvae
Where do flea larvae hang out?
- Migrate away from light
- Migrate into carpet and soil
- Base of carpet
- Cracks and crevices of hardwood flores
- Negative phototaxis and positive geotaxis
- <15% of larvae placed in carpet move more than 8 inches before they pupate
How long do flea larva last?
- 5-11 days
- If they find appropriate habitat and survive, the will pupate within 8-34 days
What environments can kill flea larva?
- Freezing
- Direct sunlight
- High temperature >95°F
- Relative humidity >50%
How long can pupal stage last?
- Usually lasts 8-9 days
- can survive up to 50 weeks
- Basically they spin a silk-like cocoon
- Silk fibers are sticky and coated from debris from the environment
- Inside, the larva undergoes metamorphosis
Can pupal stage resist desiccation and temperature?
- Yes
When does the pupal stage emerge?
- As adult fleas from the cocoon when stimulated by exhaled CO2, vibrations, and heat
- Delayed emergence if no emergence stimuli
Once an animal gets fleas, what happens?
- male and female fleas required for patent infestation
- Female flea initiates feeding immediately
- Female secretes pheromones
- Mating occurs
- Within 24 hours female fleas begin laying eggs and can produce 40-50 eggs each day
Source points outdoors for flea larva
- Under decks and crawl spaces
- Dark spaces
- Shrubs and bushes
Source points for fleas indoors
- Couches
- Cracks in the wood floors
How long can flea outbreaks take to fully control?
- Up to 2-3 months
Under what deadline must adult fleas find a host? and what will happen if they don’t find them?
- 1-2 weeks or they die
What attracts emerged adult fleas, and what is a stimulus for the jump response?
- Attracted to light (phototaxis)
- Stimulus for jump response is a decrease in light intensity (shadow)
- May bite humans before finding their preferred hosts
Will adult fleas die in the winter if they’re on a host?
- Nope, they can survive
- Important because they can survive on untreated dogs and cats, or other wildlife
What will happen to eggs, larva, and pupae in freezing temperatures?
- No
What does it mean that C. felis are permanent ectoparasites?
- They prefer a permanent host, even though they can transfer from host to host
- Therefore,treatment should be directed at all animals in the household
How quickly does C. felis feed?
- seconds to minutes
- 90-95% feed within 5 minutes to 1 hour
- Females can consume 10x body weight within 24 hours and 15x body weight thereafter
Do we have products that can stop fleas from feeding?
- No
Pathophysiology of flea allergy? What type of hypersensitivity?
- Hypersensitivity
- Type I and Type IV hypersensitivity (most have both)
- IgE mediated reactions
- Cutaneous basophil hypersensitivity
How do animals become sensitized to fleas?
- Repeated exposure
Why don’t all dogs react to flea bites?
- Some dogs may have immunologic tolerance rather than hyposensitization
Where is the flea antigen found?
- Present in saliva
- Multiple antigens
Is it technically accurate that a single flea bite will produce a clinical reaction in a hypersensitive animal and the animal will react for up to two weeks?
- Not really accurate
- Depends more on degree of hypersensitivity and number of fleas and antigen injected
Where are the largest # of eggs found?
- WHere pet spends most of its time
What is more successful: preventative flea control or waiting until the flea population is established?
- Preventative is more helpful
What is the primary cause of flea infestations?
- Acquisition of newly emerged fleas from an infested environment
- Direct transfer of fleas from 1 host to another is possible though
Can dogs or cats achieve natural desensitization therapy?
- No
How long is flea bite hypersensitivity maintained?
- Years
What are factors that favor development of FAD?
- Intermittent exposure
- First exposure to fleas later in life
- Animals with environmental allergies (atopy)
Are dogs with FAD pruritic?
- YES
Where are dogs with FAD pruritic?
- Caudal dorsal back
- Flank
- Ventral abdomen
- Can be generalized!
- Basically where the dog would wear pants
What lesions do we see with flea allergy dermatitis?
- Primary papular eruptions
- Self-trauma/secondary lesions (crusting, scaling, alopecia, lichenification, acute moist pyotraumatic dermatitis, secondary pyoderma)
What is the name of “hot spot” associated with FAD?
- Acute moist pyotraumatic dermatitis
Are cats with FAD pruritic?
YES
Where are cats with FAD pruritic?
- Neck
- Tail base
- Can be generalized
What lesions do we see with feline FAD?
- Crusted papules = miliary dermatitis**
- Pruritus with no lesions
- Alopecia (excessive grooming)
- Esoinophilic granuloma complex (indolent ulcers, esoinophilic plaques, esoinophilic granulomas)
What are parts of the eosinophilic granuloma complex?
- Indolent ulcers
- Eosinophilic plaques
- Eosinophilic granulomas
Diagnosis of Flea allergy dermatitis?
- Clinical diagnosis and response to treatment
- Clinical signs
- Presence of fleas and/or flea feces (dirt)
What are flea-nial owners?
- WHere are the fleas?
- Cats are very efficient groomers
- Other animals in the home may be carriers!
- Infestations at home!
- Threshold phenomenon
- Outdoor exposure is huge!***