Dermatology > Flea allergy > Flashcards

Flea allergy Flashcards

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1
Q

What are fleas?

A
  • Small, brown, wingless bloodsucking insects
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2
Q

Flea order

A
  • Siphonaptera
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3
Q

What is the major flea of cats and dogs?

A
  • Ctenocephalides felis felis
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4
Q

What are the two main fleas that affect dogs and cats?

A
  • Ctenocephalides felis felis (#1)

- Echidnophaga gallinacean (Poultry sticktight flea)

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5
Q

C. canis

A
  • Probably extinct in the US
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6
Q

What is the flea of humans and medium sized mammals (fox, possum, raccoon, etc.)?

A
  • Pulex irritans
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7
Q

Where is the sticktight flea (Echidnophaga gallinacean) found?

A

SE US and Florida

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8
Q

What is the life cycle of C. felis fleas (basic)?

A
  • Eggs –> 3 larval stages –> pupa –> adult
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9
Q

How long does the entire life cycle take for C. felis?

A
  • 3-4 weeks
  • Can be completed in as little as 12-14 days
  • Can take up to 50 weeks
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10
Q

Where do fleas come from?

A
  • 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
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11
Q

What does C. felis development require?

A
  • Warm temperature and humidity >50%

- Times vary depending on temp and humidity

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12
Q

Where are eggs laid?

A
  • Laid on the host and FLL OF ONTO THE ENVIRONMENT
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13
Q

How do flea eggs handle freezing or low humidity?

A
  • They don’t (they die)
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14
Q

Flea eggs - how long to hatch

A

Usually around 2-10 days

  • May go dormant and fall and not hatch for 3-4 months
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15
Q

What do larva feed on?

A
  • 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
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16
Q

Where do flea larvae hang out?

A
  • 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
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17
Q

How long do flea larva last?

A
  • 5-11 days

- If they find appropriate habitat and survive, the will pupate within 8-34 days

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18
Q

What environments can kill flea larva?

A
  • Freezing
  • Direct sunlight
  • High temperature >95°F
  • Relative humidity >50%
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19
Q

How long can pupal stage last?

A
  • 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
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20
Q

Can pupal stage resist desiccation and temperature?

A
  • Yes
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21
Q

When does the pupal stage emerge?

A
  • As adult fleas from the cocoon when stimulated by exhaled CO2, vibrations, and heat
  • Delayed emergence if no emergence stimuli
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22
Q

Once an animal gets fleas, what happens?

A
  • 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
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23
Q

Source points outdoors for flea larva

A
  • Under decks and crawl spaces
  • Dark spaces
  • Shrubs and bushes
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24
Q

Source points for fleas indoors

A
  • Couches

- Cracks in the wood floors

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25
How long can flea outbreaks take to fully control?
- Up to 2-3 months
26
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
27
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
28
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
29
What will happen to eggs, larva, and pupae in freezing temperatures?
- No
30
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
31
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
32
Do we have products that can stop fleas from feeding?
- No
33
Pathophysiology of flea allergy? What type of hypersensitivity?
- Hypersensitivity - Type I and Type IV hypersensitivity (most have both) - IgE mediated reactions - Cutaneous basophil hypersensitivity
34
How do animals become sensitized to fleas?
- Repeated exposure
35
Why don't all dogs react to flea bites?
- Some dogs may have immunologic tolerance rather than hyposensitization
36
Where is the flea antigen found?
- Present in saliva | - Multiple antigens
37
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
38
Where are the largest # of eggs found?
- WHere pet spends most of its time
39
What is more successful: preventative flea control or waiting until the flea population is established?
- Preventative is more helpful
40
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
41
Can dogs or cats achieve natural desensitization therapy?
- No
42
How long is flea bite hypersensitivity maintained?
- Years
43
What are factors that favor development of FAD?
- Intermittent exposure - First exposure to fleas later in life - Animals with environmental allergies (atopy)
44
Are dogs with FAD pruritic?
- YES
45
Where are dogs with FAD pruritic?
- Caudal dorsal back - Flank - Ventral abdomen - Can be generalized! - Basically where the dog would wear pants
46
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)
47
What is the name of "hot spot" associated with FAD?
- Acute moist pyotraumatic dermatitis
48
Are cats with FAD pruritic?
YES
49
Where are cats with FAD pruritic?
- Neck - Tail base - Can be generalized
50
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)
51
What are parts of the eosinophilic granuloma complex?
- Indolent ulcers - Eosinophilic plaques - Eosinophilic granulomas
52
Diagnosis of Flea allergy dermatitis?
- Clinical diagnosis and response to treatment - Clinical signs - Presence of fleas and/or flea feces (dirt)
53
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!***
54
If you don't find fleas or flea dirt, does that rule out a diagnosis?
- No
55
What might you find in the fecal of an animal that supports a diagnosis of FAD?
- Tapeworms! | - Dipylidium caninum
56
What tests are supportive of FAD?
- Allergy testing - bloodwork - Biopsy
57
Bloodwork that suggests FAD
- Eosinophilia
58
SKin biopsy of FAD
- Perivascular dermatitis with eosinophila
59
By the time an owner notices fleas, how long have immature flea stages been developing in the home?
- 1-2 months
60
What is the name for the group of immature flea stages that provide an ongoing source of new adult fleas?
- Biomass
61
Treatment principles for FAD
1. Treat secondary infections (Pyoderma, Malassezia dermatitis) 2. Treat pruritus accordingly 3. Client education is important 4. Treat all animals in the environment
62
Differential diagnoses for FAD?
- Food allergies - Environmental allergies - Ectoparasites (scabies, cheyletiellosis)
63
What are some questions to ask when choosing flea control?
1. Is the animal hypersensitive (if so, be more aggressive)? 2. Where do you live/work? (does it freeze over) 3. What products does your practice carry? 4. Is the pet bathed frequently? 5. Is the environment already infested?
64
Causes of treatment failure for FAD
- Poor client compliance (often result of poor client education and failure to convince the owner of the problem) - Suboptimal treatment regiment - Insecticide resistance (not as frequent; more likely failure to treat flea infested source or newly hatched fleas from pupal stage) - Incorrect or incomplete diagnosis (e.g. other allergy or concurrent allergy)
65
Are adulticide flea collars with organophosphates and pyrethroids effective?
- No - OTC - There is resistance
66
Is Brewer's yeast effective for flea repellent?
- No | - Neither is diatomaceous earth or garlic
67
What treatments were used to treat the premises and eliminate immature stages?
- Insecticides - Insect growth regulators (IGRs) - Flea dips - Flea collars - Flea powders - e.g. RAID - No residual activity
68
What are current recommendations for controlling infestations?
- preventing reproduction!
69
Describe the two mainstays of breaking the cycle of FAD?
1. Effective residual adulticides to kill fleas within 24 hours (or before they can begin to lay eggs) 2. Use of IGRs or insecticides to kill any eggs that are produced (methoprene/pyriproxyfen or lufenuron)
70
What are the two ways that you can look at speed of kill, and which is most important for control?
1. Initial speed of kill | 2. Residual speed of kill
71
Initial speed of kill - how do most products rank?
- Most products do a good job and kill within 24 hours
72
Residual speed of skill - definition?
- How long they kill newly acquired fleas
73
Importance of residual speed of kill
- Killing newly acquired fleas fast enough - Prevent flea reproduction - Reduce injection of antigens and minimize FAD - Provide client satisfaction
74
How long until most monthly products decrease their residual efficacy and speed of kill?
- most in 2 weeks | - Then it won't be able to kill within the 24 hour window, which is necessary
75
Further factors that can decrease the residual speed of kill of most adulticides?
- under-dosing by client - bathing/swimming - Not all flea strains are equally susceptible
76
How effective are isoxazolines?
- Very effect
77
MOA of isoxazolines
- Inhibit GABA and glutamate gated chloride channels
78
Where do isoxazolines circulate?
- in plasma proteins
79
Route of elimination of isoxazoline?
- Hepatic
80
Examples of isoxazolines
- Fluralaner (Bravecto) - Afoxolaner (Nexgard) - Sarolaner (Simparica) - Lotilaner (Credelio)
81
Initial speed of kill and residual speed of kill for Bravecto (fluralaner)?
- Initial: 80% by 4 hours and 100% by 12 hours | - Residual speed of kill is 100% up to 12 weeks out
82
Initial and residual speed of kill of Bravecto, Nexgard, Simparica, Credelio
- Initial is 100% for Bravecto, Nexgard, Simparica, and Credelio (Nexgard and Simparica work the fastest) - Residual is 97% 4 weeks out and 100% for everything else - Bravecto is still strong at 8 weeks
83
How long does Fluralaner work vs Afoxolaner, Sarolaner, Lotilaner?
- Fluralaner is 3 months - Afoxolaner is 28 days - Sarolaner and Lotilaner are 30 days
84
Which isoxazolines are safe for animals with food allergies?
- Fluralaner or Bravecto (hydrolyzed pork) | - Sarolaner or Simparica (hydrolyzed soy)
85
What other ectoparasites do isoxazolines treat/prevent?
- Ticks - Demodex mites - Scabies - Otodectes
86
Nitenpyram - speed of kill?
- Kills fleas in 30 minutes - 100% gone by 24 hours, but residual activity doesn't last for even 48 hours - Helps create a "flea bubble" with use of other adulticides - Every other day for 1 month - Also treats maggots
87
Speed of kill and residual kill for spinosad (comfortis) and spinosad + milbemycin oxime (Trifexis)
- Speed of kill is 100% in 4 hours - Labeled for use for 30 days - They lose efficacy much more quickly
88
What does Trifexis (spinosad + milbemycin oxime) work against
- Heartworm and GI parasites
89
Allergies with Trifexis and Comfortis?
- Both are beef flavored
90
Mechanism of capstar?
- neonicotinide - Binds nicotinyl ACh receptors on postsynaptic neurons, causing paralysis and death - Paralyzes flea mouthparts prior to injecting saliva
91
Mechanism of spinosad (comfortis/trifexis)?
- Binds nicotinyl ACh receptor on postsynaptic neurons, causing paralysis and death
92
Mechanism of imidocloprid (Advantage)/
- Binds to insect's nicotinyl acetylcholine receptor sites on postsynaptic neurons - Mammalian muscarinic acetylcholine receptors do not bind imidocloprid effectively - Adheres to hair and skin and not absorbed systemically - Kills by contact - hair is larvicidal in environment
93
Imidocloprid route?
- Topical spot on
94
Is Imidocloprid (advantage) absorbed?
- No
95
What can reduce efficacy of imidocloprid?
- Bathing/swimming
96
Labeled length of imidocloprid?
- 30 days
97
Imidocloprid with permethrin (K9 advantix) - can it be used on cats?
- NO it can kill them | - Useful against ticks though
98
Advantage multi (imedicloprid with moxidectin) - what is it effective against?
- Heartworm | - Also miticidal properties if used every 2 weeks for 3 consecutive treatments
99
What is the drug in seresto?
- Imidocloprid with flumethrin | - Slow release collar
100
How long is imidocloprid plus flumethrin useful for (seresto)?
- 8 months, but reduced efficacy if you bathe your dog regularly
101
What is seresto useful against?
- Fleas and lice (fleas and lice) | - Ticks and scabies (flumethrin)
102
Selamectin - drug type?
- Avermectin
103
How is selamectin absorbed?
- Systemically
104
WHere does selamectin form reservoirs?
- SEbaceous glands
105
What life stages does selamectin kill?
- adulticide and ovicide
106
Is selamectin more useful for dogs or cats?
- More useful for cats
107
How long is selamectin useful?
- 30 days | - Efficacy lost in 2-3 weeks
108
What is selamectin active against and in which species?
- Heartworm prevention (dogs and cats) - Scabies (dogs) - Otodectes (dogs and cats) - Hookworms (cats) - ROundworms (cats) - Ticks (dogs)
109
Mechanism of selamectin?
- Induced neuromuscular paralysis by increasing chloride permeability of glutamate-gated chloride channels
110
Vectra 3D active ingredients and mechanism
- Dinotefuran/pyriproxifen/permethrin - Neonicotinoid - Bind flea postsynaptic nicotinic acetylcholine receptors
111
Spectrum of action for dinotefuran/pyriproxifen/permethrin?
- Labeled for fleas, ticks mosquitoes
112
Fipronil (Frontline)mechanism
- Inhibits GABA mediated chloride - Collects in sebaceous glands and hair follicles, then redistributes to skin surface - Not systemically absorbed - Kills by contact
113
What is fipronil toxic to?
- Rabbits
114
Spectrum of fipronil?
- Kills adult fleas and ticks
115
List the residual adulticides?
- Isoxazolines - Capstar (nitenpyram) - Spinosad (comfortis) Imidocloprid (Advantage) - Selamectin (Revolution) - Dinotefuran/pyriproxifen/permethrin (Vectra 3D) - Fipronil
116
WHere can you use insect growth regulators?
- On pets or applied to the environment
117
How do insect growth regulators work (which life stage of the flea to they impact)?
- prevent flea eggs from hatching - Larvae cannot pupate - Often combined with Bravecto to break the cycle
118
Examples of insect growth regulators
- Methoprene (Frontline plus) | - Pyriproxifen (Vectra 3D)
119
Mechanism of insect growth regulators
- Juvenile hormone mimic - disrupts embryonic and post embryonic development - Prevents flea eggs from hatching; existing larvae cannot pupate - In general, doesn't affect adult flea
120
Insect development inhibitor examples
- Lufenuron
121
Methoprene more info
- Available in sprays, collars - Eggs exposed within 24 hours after being laid failed to hatch - UV sensitive
122
Pyriproxyfen more info
- Sprays, collars, Vectra 3D - Affects egg formation as well - UV stable - Doesn't wash off
123
Mechanism of insect development inhibitors
- Environmental control administered to pet - Interferes with chitin synthesis (eggs and larvae) - Eggs non-viable because larval exoskeleton formation inhibited
124
Is it okay to use lufenuron (Program, sentinel) as a primary flea control?
- NO | - No adulticide, so the fleas will still jump on and cause problems
125
Flavor of lufenuron
- Beef
126
What additional drug is in sentinel besides lufenuron?
- Milbemycin oxime
127
How to manage the itch with FAD?
- Look for and treat all secondary infections | - Put out the fire (the itch) for 2-3 weeks
128
How to put out the itch for FAD?
- Corticosteroids: short, tapered anti-inflammatory dose/course (avoid injectables) - Apoqel (oclacitinib) - Cytopoint (lokivetmab)
129
What secondary infections are most likely with FAD?
- Yeast and pyoderma
130
Antihistamines for managing the itch?
- Not useful! | - Mediocre at best
131
How long can cytopoint provide relief?
- Approximately 30 days
132
Which drugs are recommended for cats?
- Selamectin | - Fluralaner
133
Which drugs are recommended for dogs
- Fluralaner | - Advantage K9
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