Skin Flashcards
What are the two most significant fleas affecting companion animals?
Ctenocephalides felis and canis
How many ctenidiado species of Ctenocephalides have?
2 -> one genal and one pronotal
How would you differentiate Ctenocephalides felis from Ctenocephalides canis?
The female head of C. canis is not twice as long as it is high and is rounded anteriorly as opposed to pointed
What do adult fleas and larvae feed on?
Adults: blood
Larvae: adults faeces
Which stages of the flea are on the host and which are in the environment?
Adults on the host; eggs laid on the host but will fall off
Eggs, larvae, pupae and pre-emerged adults in the environment
What percentage of the flea population lives and feeds on the animals?
About 5%
Irritation from flea bits is usually from what?
Physical presence of fleas, flea movement, action of sucking blood, injection of saliva
What is FAD and what is it a reaction to?
Flea allergy dermatitis
Salivary antigens
What are three things that the pathogenesis of FAD depends on? (Note: there are more than three)
Genetic predisposition Number of fleas and amount of antigen Frequency of exposure Age at first exposure Other skin disease Effects of previous or current treatment
What are the clinical signs of FAD?
Dermatitis in the dorsal lumbosacral area (or generalised in severe cases) in dogs of any age
What is feline miliary dermatitis?
FAD in cats
Common lesions associated with FMD?
A pruritic, erythematous papule usually on the head, neck and dorsal lumbosacral regions (before self-trauma)
How would you diagnose FAD infections?
Clinical signs and history
Response to treatment
Visualisation of fleas or flea faeces on host
Allergy testing (intradermal and ELISA)
Outline the components of an Integrated Flea Control program.
Use an effective residual adulticide
Use an insect growth regulator (IGR)
Mechanical control methods
Education of the pet owner
What adulticides would you use for a FAD case?
Phenylpyrazoles (fipronil, pyripole); Neonicotinoids (imidacloprid, nitenpyram); Avermectins (selamectin); Semicarbazone (metaflumizone); Spinosyns (spinosads); Pyrethrins and Pyrethroids
What parasites is Fipronil (Frontline) active against?
Fleas, lice and ticks
What is the MOA of Fipronil?
Blocks passage of chloride ions through GABA and glutamate-gated chloride channels –> causes hyperexcitation and death
Frontline plus has the added ingredient of (S)-methoprene. What does this additive help achieve?
Kills all flea stages in the dogs surroundings (helps prevent reinfestations)
Pyriprole kills fleas and ticks. What is it an analogue of?
Fipronil
Advantage is an adulticide treatment that works against fleas and lice in dogs and cats. What is its active ingredient and how would you apply it?
Imidacloprid
Spot-on
Imidacloprid + pyriproxyfen =
Advantage II
Advantix is active against fleas and ticks but cannot be used on cats, Why?
Imidacloprid + permethrin
Permethrin is extremely toxic to cats
Advocate is for dogs and cats to control fleas, lice and a number of mites. It is also active against L3 and L4 of Dirofilaria immitis, how?
Imidacloprid + moxydectin
What is the ‘rapid flea removal adulticide’ and why is it considered rapid?
Nitenpyram (Capstar)
Begins to work within 15-30 mins of administration
Kills >95% of fleas within 3-6 hours
Selamectin (Revolution/Stronghold) is active against which life stages of the flea?
Eggs, larvae and adults
The action of which flea treatment remains persistent for approximately 1 month because of extensive plasma protein binding?
Spinosad (Comfortis)
Panoramis is a chewable tablet for dogs. What are it’s active ingredients?
Spinosad and milbemycin oxyme
Insect Growth Regulators are used for what?
To interfere with growth and development of immature stages of the insects –> eliminate environmental stages (prevent reinfestations)
Why are Insect Growth Regulators usually used in combination with an adulticide?
IGRs generally have no effect on adults and it reduces the likelihood that resistance will develop
Insect Growth Regulators include:
Juvenile hormone analogues (methoprene, fenoxycarb, pyriproxyfen)
Insect development inhibitors (lufenuron, cyromazine)
How do Juvenile Hormone Analogues work?
Mimic the activity of naturally occurring juvenile hormones (ovicidal and larvicidal)
How do Insect Development Inhibitors work?
Inhibit chitin synthesis –> females will produce non-viable eggs
Which louse has a head wider than the thorax and of rectangular shape that infests dogs and cats?
Trichodectes canis
How would you treat an infestation of lice on the dog?
Pyrethrin/pyrethroids, Fipronil, Selamectin, Imidacloprid
Most common louse infecting cats?
Felicola subrostrata (head is triangular)
Can dogs become infected with Sarcoptes scabiei directly or indirectly?
Both. But the correct temperature and humidity needs to be present for the mites to be able to live in the environment
Describe the pathogenesis of Sarcoptes scabiei.
Secretions, faeces and eggs will induce both immediate and delayed hypersensitivity = intense pruritis
What is the distribution of lesions for Sarcoptes scabiei?
Ear margins, elbows, abdomen and hocks
What are the clinical signs associated with Sarcoptes scabiei infections?
Erythema, papules, pruritis, alopecia and crusts
Extensive excoriations and self-trauma due to pruritis
Emaciation and death may occur in extreme cases
What are some differential diagnoses of Sarcoptic mange?
Allergy (flea bites, food, contact) Cheyletiellosis Demodicosis Pediculosis Malassezia dermatitis
How would you go about treating a case of sarcoptic mange?
Treat all in-contact dogs with Selamectin and Moxidectin
What parasite causes Notoedric mange and who is its host?
Notoedres cati
Cats and rabbits
What are the clinical signs associated with notoedric mange?
Alopecia, erythema, thick grey crusts, intense pruritis on the edge of the pinna
Excoriations and self-trauma may result in bacterial complications
How would you treat a clinical case of Notoedric mange?
Treat all in-contact cats with Selamectin and Moxidectin
What is the name of the ear mite?
Otodectes cynotis
Are there any human health concerns regarding Otodectes cynotis infections?
Yes, after close contact with an infected animal, a transient papular dermatitis may develop
What are the clinical signs associated with Otodectes cynotis?
Brownish waxy exudate/cerumen (can dry to form crust)
Shaking of head, hematoma formation and self-trauma will most likely develop due to the intense pruritis
How would you treat an infection with Otodectes cynotis?
Treat all affected and in-contact animals.
Topical acaricides may be sufficient or Selamectin and Moxidectin are available as systemic treatments
Is Demodicosis contagious?
No
What kind of animals are susceptible to Demodicosis?
Those with a hereditary T-cell defect or some sort of immunosuppression
What is localised Demodicosis?
Less than six lesions or only one body region affected and most common places are the head and forelegs. Up to 90% of cases may resolve spontaneously while 10% will become generalised (irrespective of treatment).
What is generalised Demodicosis and how would it present?
More than 6 lesions and involvement of 2 or more body regions or feet. Adult onset is usually as a result of immunocompetency or because of an underlying condition (endocrine). Alopecia, erythema and scaling will be seen and a secondary bacterial infection may also be present.
How would you diagnose Demodicosis?`
Clinical signs
History
Microscopic examination of skin scrapings
How would you go about treating a case of generalised Demodicosis?
Identify underlying condition and correct
Treat concurrent bacterial infection
Acaricidal therapy (Amitraz, Moxidectin, Milbemycin oxime)
What mites are responsible for Feline Demodicosis?
Demodex cati and Demodex gatoi
What is the pathological name for the condition called the “walking dandruff”?
Cheyletiellosis
What are three morphological features of Cheyletiella?
Big palps that end with claws
Legs end with comb-like structures
Feather-like setae
What is the most important ectoparasite of dogs and cats?
Fleas
What clinical signs are usually associated with Cheyletiella infections?
Lesions mainly over dorsum
Excessive scaling
Pruritis
Alopecia, erythema, papules etc.
What makes the parasite Neotrombicula autumnalis stand alone from the other mites of dogs and cats?
Only the larvae are parasitic and all other stages are in the environment.
Do Neotrombicular autumnalis larvae feed on blood?
No, they feed on digested skin cells and lymph.
What are the common clinical signs of Neotrombicula infections and where will they locate usually?
Pruritis, erythema, papules, scales, alopecia.
Skin that comes into contact with the ground (feet, head and ventral body).
How would you treat a case of Neotrombicula autumnalis?
Fipronil for dogs and cats.
Permethrin and pyriproxyfen for dogs only.
Which tick is the most common cause of tick toxicosis in Australia?
Ixodes holocyclus
What position is the anal groove in Ixodes holocyclus?
I. holocyclus has an anterior anal groove
What are some other distinguishing features of Ixodes holocyclus?
No eyes
No festoons
Mouthparts are longer than basis capituli
How do Ixodes holocyclus and Ixodes cornuatus differ morphologically?
Females of I. cornuatus have distinct cornua
How many host tick is Ixodes holocyclus?
3 host tick
What does the distribution of Ixodes holocyclus depend on?
Fairly consistent humidity (susceptible to desiccation)
Presence of natural hosts (bandicoot, possums and koalas)
What effect does the holocyclotoxin of Ixodes holocyclus have on the body?
Causes transmission disturbance at the neuromuscular junction by inhibiting the release of ACh which results in flaccid paralysis.
How can a dog develop immunity to the effects of Ixodes holocyclus?
Long term, low dose exposure. Urban dogs unlikely to acquire some degree of immunity.
How would you treat a case of tick paralysis?
Remove ALL parts of the tick
Administer anti-toxin serum
Support therapy
How does the Tick Antitoxin Serum (TAS) work?
Neutralises circulating toxin however, its efficacy varies and adverse reactions can develop.
What products would you recommend for tick prevention?
Frontline, Nexgard, Advantix, Permoxin, Kiltix collar, Preventic collar
What is the common name for the tick Rhipicephalus sanguineus?
Common brown dog tick (kennel tick)
Is this tick a 2 host tick and what does it transmit?
No, it is a 3 host tick.
It transmits Babesia canis vogeli
Why is Rhipicephalus sanguineus unusual among other ticks?
It can complete its entire lifecycle indoors
What are the predilection sites for Rhipicephalus sanguineus?
Between paws and in the ears (but can be anywhere on the hosts skin)
What are the clinical signs associated with R. sanguineus?
Anaemia in heavy infestations
Inflamed nodule at attachment site
Signs of tick-borne diseases
