Parasite Questions Flashcards
- Describe the difference between EPA and FDA labeled insecticides in dogs and cats.
a. EPA = topical insecticides, off label application is illegal
b. FDA = oral and topicals that go systemic, off label application is allowed with restrictions
- What is the drug class and mechanism of action of dinotefuran?
a. Third generation neonicotinoid
b. Bind nicotinic receptors in the nerve synapse, causing continuous nerve stimulation and death
- Describe the clinical signs of stephanofilariasis in cattle.
a. Circumscribed dermatitis along the ventral midline, with adult worms located in the superficial dermis
- Which of the following is NOT true about how helminth infestations can protect against food allergy. (Multiple Choice)
a. Helminths induce Treg cell responses
b. Helminths prime for Th2-based, non allergic responses
c. Helminths trigger mucosal barrier thickening and increased IgA production
d. Helminths induce non-specific IgE to saturate IgE binding sites on mast cells
c. Helminths trigger mucosal barrier thickening and increased IgA production
- Which of the following is true regarding the life-cycle of Otodectes cynotis? (Multiple Choice)
a. Life cycle lasts 3 weeks and has 4 stages: larva, protonymph, deutonymph and adult
b. Life cycle lasts 6 weeks and has 4 stages: larva, protonymph, deutonymph and adult
c. Life cycle lasts 3 weeks and has 3 stages: larva, nymph and adult
d. Life cycle lasts 6 weeks and has 3 stages: larva, nymph and adult
a. Life cycle lasts 3 weeks and has 4 stages: larva, protonymph, deutonymph and adult
- True/False – All species of hookworm complete their life cycles via the skin.
a. False – Uncinaria stenocephala are poor blood suckers and do not complete their life cycles via skin, unlike Ancylostoma spp.
- What are the psoroptic mites in goats? Where are their lesions distributed?
a. Psoroptes cuniculi = ear canal
b. P. bovis = pinnae, head, face, pasterns, interdigital area
- What are the two structures in this biopsy (yellow and white arrows)?
Answer:
a. White arrow = superficial parasite (scabies most likely, Cheyletiella also possible)
b. Yellow arrow = egg
- What is the causative agent of chorioptic mange in cattle?
a. Chorioptes bovis
- What is the mechanism of action and drug class of d-Limonene.
a. Class = volatile citrus oil extract
b. MOA = dessicant – removes epicuticular oils
- Match the parasite with its name.
a. Dermanyssus gallinae
b. Lynxacarus radovskyi
c. Chiggers (Neotrombicula autumnalis, Eurotrombicula alfreddugesi)
d. Otodectes cynotis
e. Pneumonyssoides caninum
f. Cheyletiella
g. Sarcoptes scabiei
h. Notoedres cati
Answers: a= 3, 5; b = 9; c = 2; d = 8; e = 6; f = 4; g = 7; h = 1
- What is the drug class and mechanism of action of fipronil?
a. Class = phenylprazole
b. Antagonize insect GABA receptors which causes flaccid paralysis
- What are the three species of hookworms in small animals?
a. Ancylostoma braziliense
b. Ancylostoma caninum
c. Uncinaria stenocephala
- What environment do poultry mites favor?
a. Nests and cracks in cages and poultry houses
- You want to treat fleas on a rabbit. What product do you NOT use?
a. Fipronil – it is toxic to rabbits
- Can you give Amitraz to horses?
a. No
- A dog presents with crusted, hyperkeratotic footpads. Give 5 differentials for this condition.
Answer:
a. Hookworm dermatitis
b. Erythema multiforme
c. Pemphigus foliaceus
d. Ichthyosis
e. Idiopathic or familial paw pad hyperkeratosis
f. Hepatocutaneous syndrome
g. Dermatophytosis
h. Leishmaniosis
i. Zinc responsive dermatosis
j. Pelodera strongyloides infection
- What is the etiology of pruritus and ear canal debris with Otodectes cynotis infection?
a. Hypersensitivity reaction to the mite antigen, which the patient is exposed to early in the infestation
b. Ear canal epithelium is irritated and fills with cerumen, blood, and mite debris
- Where do the lesions of Chorioptic mange occur in cattle and what are these lesions?
a. Location = rump, tail, perineum, caudomedial thigh, caudal udder and scrotum
b. Lesions = erythema and papules with scale/crusting, variable pruritus, weight loss, hide damage, reduced milk and meat yields due to stress
- What is the mechanism of action of Amitraz? (3)
a. Monoamine oxidase inhibitor
b. Prostaglandin synthesis inhibitor
c. Alpha adrenergic agonist
- What are two main infections transmitted by Haematobia irritans (horn fly) in cattle?
a. Stephanofilariasis
b. Staphylococcus aureus
- Describe the clinical signs of hookworm dermatitis in dogs.
a. Erythematous interdigital webs and spongy/soft footpads with hyperkeratosis at pad margins
b. Ventrum abdomen, sternum, distal limbs can show red papules that become diffusely erythematous, thickened, and alopecic over time with variable pruritus
- What side effects can be seen with amitraz? Name 5. Are any of them reversible and if so, how?
a. Transient sedation – reverse with yohimbine or atipamezole
b. Pruritus
c. Bradycardia
d. Hypotension
e. Hyperglycemia
f. Hypothermia
- What are the two types of insect growth regulators? Give examples of each.
a. Juvenile hormone analogs – control early stages of metabolism/reproduction to block eggs from hatching and larval maturation
i. Example = methoprene, pyriproxyfen
b. Chitin synthesis inhibitors
i. Example = lufenuron
- What is the drug class and mechanism of action of imidacloprid?
a. Drug class = chloronicotinyl nitroguanidine
b. MOA = nicotinic receptor antagonist on post-synaptic neurons, causing flaccid paralysis
- What environment do hookworms favor?
a. Grass and soil of runs and paddocks in the spring/summer in cool climates
- What are the types of lice in goats?
a. Mallophaga = Damalina caprae, D. crassipes, D. limbate (chewing)
b. Anoplura = Linognathus stenopsis, L. africanus (sucking)
- What are three ways that ticks can harm their hosts?
a. Bite injuries can lead to secondary infections or myiasis
b. Sucking blood
c. Transmit viral, protozoal, bacterial, rickettsial disease
d. Tick paralysis
- What is the drug class and mechanism of action of metaflumizone?
a. Drug class = semicarbazone insecticide
b. MOA = block sodium channels in insects so impulses cannot be conducted, causing decreased activity and flaccid paralysis
- What is the drug class of pyrethrins and their mechanism of action?
a. Drug class = volatile oil extract of chrysanthemum flower
b. MOA = block closure of ion gates of sodium channels during repolarization, leading to spontaneous depolarization and hyperactivity paralysis
- Describe the life cycle of Dermanyssus gallinae:
a. Length = 8 days
b. Adults lay up to 7 eggs after blood meal
c. Eggs hatch to 6-legged nymphs which moult to 8-legged protonymphs within 12 – 36 hours
d. Protonymphs moult to deutonymphs 15 – 45 hours after feeding
e. Deutonymphs molt to adults 15 – 45 hours after fedding
- What cutaneous parasite are donkeys more susceptible to than horses and what are their clinical signs?
a. Besnoitia bennetti
b. Signs = cysts on the skin, nares and sclera +/- skin scaling
- Why can moxidectin be used in dogs with ABCB1 gene mutations?
a. Moxidectin is a poor P-glycoprotein receptor substrate, so it is safer compared to ivermectin
- What parasites can sulfur be used to treat? List four other properties it also has.
a. Parasites = non-follicular mites (Sarcoptes, Notoedres, Cheyletiella, lice)
b. Other properties = fungicidal, keratolytic, anti-pruritic, bactericidal
- How long is the life cycle of Cheyletiella? Where do the eggs and the life stages live?
a. Life cycle = 21 days
b. Mite lives only on the host and eggs are shed into the environment (attached onto hairs)
- What are the two mechanisms of action of avermectins and milbemycins?
a. Potentiate release and effects of GABA, causing hyperactivity paralysis
b. Glutamate-gated chloride channel agonist in parasites, causing chloride influx and flaccid paralysis
- A dog is found to have hyperkeratotic paw pads and hookworm eggs on fecal examination and paw scrapings. What do you expect to find on biopsy?
a. Rare larvae (if present surrounded by neutrophils, eosinophils, and mononuclear cells) with larval migration tracts through the epidermis and neutrophilic/eosinophilic perivascular dermatitis
- Name four parasites that can live in the stratum corneum of large and small domestic species and be visible on biopsy.
a. Psoroptes, Chorioptes, Sarcoptes, Cheyletiella
- What stage of larvae enter the dog’s skin in an Ancylostoma infection?
a. 3rd stage larvae
- What gender of flea is more susceptible to oral products and why?
a. Females – they feed more and so ingest more of the product in the blood
- What can Haemotopinus suis be a vector for? What 2 species can it transmit this disease between?
a. Swinepox – can pass to humans from pigs
- What is the mechanism of action of ivermectin?
a. Activation of Chloride channels, causing chloride influx and flaccid paralysis
b. Potentiate release and effects of GABA to cause hyperactivity paralysis
- Why doesn’t ivermectin kill trematodes and cestodes?
a. They lack GABA system and ivermectin is a GABA receptor agonist in its mechanism of kill
- What are 3 reportable parasites in goats?
a. Psoroptes cuniculi and P. bovis
b. Screw worms
c. S. scabiei var ovis
- What is the mechanism of ivermectin toxicity?
a. Altered function of P-glycoprotein, which limits penetration of some substances through the blood-brain barrier, placenta, testes, and intestines
b. The altered gene is a mutation in nt230 of the ABCB1 (MDR1) gene
- Where does selamectin accumulate externally? (3 places)
a. Sebaceous glands, hair follicles, basal epithelium
- What is the mechanism of action and structure of lufenuron?
a. Structure = benzylphenol urea compound
b. MOA = inhibit chitin synthesis, which blocks embryogenesis and hatching as a result
- What is the causative agent of Psoroptic mange in cattle?
a. Psoroptes bovis.
- Name two exotic species that cannot receive fipronil due to toxicity.
a. Rabbits
b. Upland game birds (pheasant, bobwhite quail, grouse)
- What is the mechanism of action of neonicotinoids? Give an example.
a. MOA = post-synaptic nicotinic acetylcholine receptor agonist, leading to hyperexcitability paralysis
b. Nitenpyram (Capstar), Dinotefuran
- Name two types of Argasid (1) and Ixodid (2) ticks that affect horses.
a. Argasid = Otobius megnini, Ornithodorus spp.
b. Ixodid = Dermacentor albipictus, Amblyomma americanum
- What are the causative agents of Psoroptic mange in horses?
a. Psoroptes ovis, P. equi, P. natalensis, P. cuniculi
- What is the drug class and mechanism of action of selamectin?
a. Semi-synthetic avermectin
b. GABA potentiator (causes hyperexcitability paralysis) and glutamate-gated channel binder (causes flaccid paralysis)
- What is the mechanism of action of Spinosad?
a. Nicotinic acetylcholine receptor agonist, leading to hyperexcitability paralysis
- Why can’t you give spinosad and ivermectin together?
a. Spinosad inhibits P-glycoprotein function, which can lead to increased CSF levels of ivermectin and toxicity
- What is the mechanism of action of isoxazoline antiparasitics?
a. Antagonist for GABA-gated chloride channels (keeps channels closed), blocking inhibitory signals and causing hyperactivity paralysis
- Describe the clinical signs of caprine pediculosis.
a. Dermatologic = alopecia, irritation, papulo-crustous dermatitis, self-excoriation
b. Systemic = anemia, weakness, decreased productivity
- Give five signs of ivermectin toxicity in dogs?
a. Mydriasis
b. Hypersalivation
c. Lethargy
d. Ataxia
e. Tremors
f. Coma
- List three ways that arachnids are distinct from insects anatomically.
a. Lack of wings
b. Four pairs of legs
c. Fused head and thorax
- Define perionyxis.
a. Inflammation of the epidermis around a nail
- List four ways the ticks are different from mites (anatomy and host).
a. Ticks are larger with hairless or short-haired leathery body
b. Exposed armed hypostome (organ lying below the mouth)
c. Pair of spiracles near the coxae of the fourth pair of legs
d. Not host-specific
- How do you prevent re-infection of a dog with hookworm dermatitis?
a. Clean premises and dry paved runs
b. Treat dirt and gravel runs with borax
c. Routine anthelmintic treatment of all dogs in kennel
- True/ False – Damalina ovis is host specific.
a. False – it can pass between goats and sheep
- Give four differentials for these lesions in a dog.
Answer:
a. Angiostronylosis
b. Pemphigus foliaceus
c. Leishmaniasis
d. Papillomavirus
- A 10 week old kitten being fostered in a household with 2 other adult cats and one dog has been diagnosed with ear mites (Otodectes cynotis). Which animals in the household should be treated? (Multiple Choice)
a. Just the kitten
b. All cats in the household
c. All cats and the dog in the household
d. Depends on their level of direct contact with the kitten
c. All cats and the dog in the household
- Give four different characteristics between argasid and ixodid ticks.
a. Argasid = soft, less parasitic, less prolific, infest indoors
b. Ixodid = hard, highly parasitic, very prolific, infest open country
- Label each tick Argasid or Ixodid.
a. Otobius megnini
b. Rhipicephalus sanguineus
c. Dermacentor variabilis
d. Ixodes scapularis
e. Amblyoma maculatum
Answer: a = argasid, b – e = ixodid
- Match the ticks’ common name with species name.
a. Otobius megnini - Brown dog tick
b. Rhipicephalus sanguineous - Spinous ear tick
c. Amblyoma americanum - American dog tick
d. Dermacentor variabilis - Lone star tick
e. Ixodes scapularis - Black legged tick
Answer: a = 2, b = 1, c = 4, d = 3, e = 5
- What is the life cycle of the Psoroptes parasite?
a. Adult mites pierce the skin, causing fluids to leak and form crusts to cover the mites
b. Mites mate and lay eggs under crusts, then larvae hatches and moves through the crust, molting through two nymph life stages to become an adult again
c. Life cycle is completed on the single host
- How do Cheyletiella mites move around the skin and feed?
a. They live in the stratum corneum and move through tunnels of epidermal debris
b. Attach to the epidermis and pierce it with claws on either side of the mouth, then feed on fluids
- Know the common solutions used in fecal flotation technique and the recommended fecal sample size.
a. Solutions = Zinc sulfate, Sheather’s solution
b. Sample size > 5g
- Give three ways in which Norwegian or Crusted Scabies differs from ordinary scabies in dogs? (clinically)
a. High number of mites in skin scrapings
b. Absence or low intensity of pruritus
c. Formation of thick parakeratotic crusts all over the body
- How long is the screw worm life cycle?
a. 21 days in warm weather
- List three common side effects of DEET in horses.
a. Sweating
b. Irritation
c. Local skin exfoliation
- Where can Otodectes cynotis mites live on dogs and cats?
a. External ear canal, rest of head, neck, rump, tail
- Describe four aspects of Argasid tick anatomy.
a. Lack of dorsal plate
b. Sexes appear similar
c. Capitulum is not visible dorsally
d. Spiracles lie in from of third pair of unspurred coxae
- What is the causative agent of Chorioptic mange in the US?
a. Chorioptes ovis/bovis
- Where is Otobius megnini located in the US?
a. Southern and Western US
- What is the causative agent of warbles in goats?
a. Przhevalskiana silenus 3rd stage larvae
- When are chorioptes mites more prevalent in horses seasonally and why?
a. Winter – horses are more frequently stabled closer together, so they have more contact which favors parasite transmission
- Which T-lymphocyte subpopulation is consistent with generalized demodicosis infection? (Multiple Choice)
a. Increased overall lymphocytes with lower absolute numbers of CD4+ lymphocytes
b. Decreased overall lymphocytes with lower absolute numbers of CD4+ lymphocytes
c. Increased overall lymphocytes with increased absolute numbers of CD4+ lymphocytes
d. Decreased overall lymphocytes with increased absolute numbers of CD4+ lymphocytes
b. Decreased overall lymphocytes with lower absolute numbers of CD4+ lymphocytes
- Describe 3 side effects of Amitraz in horses.
a. Somnolence and depression
b. Ataxia and weakness
c. Colonic impaction
Due to alpha agonist effects
- Give the clinical signs of Psoroptic mange in horses.
a. Can be asymptomatic
b. Ear disease – head shaking, ear scratching, head shyness, lop-eared appearance (P. cuniculi)
c. Mane/tail disease and truncal dermatitis (P. ovis)
d. Nonfollicular papules, crusts, excoriations, alopecia
- What is the most common causative agent of pediculosis in pigs?
a. Haematopinus suis (Anoplura)
- How do you group ticks and what three groups do they fall in?
a. Grouped by number of hosts in the life cycle
i. One host ticks = all three instars engorge same host
ii. Two host ticks = larvae engorge/molt, then nymph drops to ground and adult seeks a new host
iii. Three host ticks = requires a different host for every instar
- Draw the life cycle of Otobius megnini.
Answer:
a. Eggs hatch into larvae within days
b. Larvae feed on lymph from ear canal immediately and turn into nymphs within 5 – 10 days of feeding
c. Nymphs feed for 1 – 7 months, then moult to adults
d. Adults live 6 – 12 months and lay eggs
- What one tick can Selamectin be used to prevent or treat?
a. Dermacentor variabilis (American dog tick)
- How long can Dermanyssus gallinae mites survive without food? Which phase doesn’t feed at all?
a. Survive up to 9 months without food
b. Nymphs don’t feed at all
- Describe how spinous ear ticks appear as larvae, nymphs, and adults.
a. Larvae = pink/yellow, 0.3cm, spherical, 3 pairs of legs
b. Nymph = blue/grey, sharp spines, 4 pairs of legs
c. Adults = fiddle shaped, not spiny, non-parasitic
- What is the life cycle of Eurotrombicula alfreddugesi?
a. Adults lay eggs on moist ground
b. Eggs hatch into red, six-legged larvae that feed on animals
c. Larve drop off animals to become nymphs, then adults
- What clinical signs do you expect to see with spinous ear tick infestation?
a. Acute otitis externa, pain, occasional convulsions +/- loss of blood and lymph
- How does the T-lymphocyte population change after clinical cure from demodicosis? (Multiple Choice)
a. There is no change from the time of diagnosis
b. CD4+ and CD8+ lymphocytes decrease over the course of treatment and return to normal by clinical cure
c. CD4+ and CD8+ lymphocytes increase over the course of treatment and return to normal by clinical cure
d. CD4+ lymphocytes increase and return to normal, while CD8+ lymphocytes remain low
c. CD4+ and CD8+ lymphocytes increase over the course of treatment and return to normal by clinical cure
- Label the correct spectrum of action for these common medications to treat cutaneous parasite infestations:
a. Imidacloprid
b. Fipronil
c. Isoxazolines (Afoxolaner, Lotilaner, Sarolaner, fluralaner)
d. Dinotefuran
e. Spinetoram
f. Selamectin
g. Deltamethrin
h. Lufenuron
i. S-methoprene
j. Pyriproxyfen
k. Amitraz
l. Moxidectin - Fleas (adult)
- Fleas (larvae/eggs)
- Ticks
- Otodectes cynotis (ear mites)
- Demodex species
- Sarcoptes scabiei
- Chewing lice
- Mosquitoes
- Sand flies
- Cheyletiella
- Neotrombicula autumnalis (chiggers)
- Notoedres cati
Answer: a = 1, 2; b = 1, 2, 3, 6, 7, 10, 11; c = 1 – 12; d = 1, 2; e = 1,2; f = 1, 2, 3, 4, 6, 10, 12; g = 1, 2, 3; h = 2; i = 2; j = 2; k = 1, 2, 3, 5, 6; l = 4, 5, 6, 10
- Match the shape of the Cheyletiella species sensory organ on the first pair of legs with its species.
a. C. yasguri
b. C. blakei
c. C. parasitivorax - Cone-shaped
- Globoid
- Heart-shaped
Answers: a = 3, b = 1, c = 2
yasguri = heart-shaped (dogs)
blakei = cone-shaped (cats)
parasitivorax = globoid (rabbits)
- In what species is Sarcoptes scabiei infestation a notifiable disease?
a. Horses
- What are three treatment aspects of spinous ear tick treatment?
a. Mechanically remove ticks with forceps
b. Spray/dip patient in pyrethroids
c. Treat otitis externa
d. Oil-based otic treatments can smother ticks
- What are four predisposing factors for Choriopties bovis infestation in horses?
a. Heavy feathering
b. Warm, humid climates
c. Dark environment
d. Overcrowding (especially common in winter)
- Where do the lesions occur from nematode infections of dogs by Pelodera strongyloides?
a. Feet, legs, perineum, lower abdomen and chest, tail
- What are the two parts of an ixodid tick?
a. Scutum (hard, chitinous shell covering dorsal surface)
b. Capitulum (visible at the anterior end dorsum)
- True/False – Ixodid ticks can be distinguished by sex.
a. True – they are dissimilar in appearance (sexually dimorphic)
- A horse presents with otitis externa, head shaking, ear rubbing, and a lop-eared appearance. Name two parasites that can be responsible for these signs.
a. Otobius megnini (spinous ear tick)
b. Psoroptes mites
- Name five parasites commonly seen on rabbits.
a. Psoroptes cuniculi (ear mite)
b. Leporacarus gibbus (fur mite)
c. Ctenocephalides felis (flea)
d. Cuterebra spp.
e. Sarcoptes spp.
f. Cheyletiella parasitovorax
- Draw the life cycle of Ixodes ticks.
Answer:
a. Eggs hatch in 2 – 7 weeks
b. Larvae feed for 3 – 12 weeks, then drop off before molting to nymphs
c. Nymphs feed for 3 – 10 days then rest for 17 – 100 days before molting to adults
d. Adults live 19 months and lay eggs
- What is the principal animal host of Rhipicephalus sanguineus?
a. Dogs in all four life stages
- What is a Knott’s test and what species can it distinguish?
a. Centrifuge anticoagulated blood and evaluate sediment for microfilaria
b. Distinguishes D. immitis, D. repens, and Acanthocheilonema species
- Give three differentials for these lesions in a horse.
Answer:
a. Irritant contact dermatitis
b. Pastern folliculitis/pyoderma (S. aureus, D. congolensis infection)
c. Chorioptic mange
d. Early lymphangitis
- List 2 – 3 common avermectin and milbemycins.
a. Avermectins = ivermectin, selamectin, doramectin
b. Milbemycins = milbemycin, moxidectin
What is the mechanism of action of selamectin and moxidectin? (Multiple Choice)
a. Enhancing chloride permeability and enhancing release of gamma amino butyric acid (GABA) at presynaptic neurons, causing paralysis of parasites
b. Inhibits GABA- and glutamate-gated chloride channels, causing uncontrolled neuronal activity with resultant paralysis
c. Acts as a nicotinic acetylcholine D-alpha receptor agonist, causing involuntary muscle contractions and tremors
d. Mimics flea juvenile growth hormone, halting development, and concentrates in female flea ovaries, causing non-viable eggs
a. Enhancing chloride permeability and enhancing release of gamma amino butyric acid (GABA) at presynaptic neurons, causing paralysis of parasites
- Compared with animals who have localized demodicosis or those that are healthy, dogs with generalized demodicosis have lower mRNA for what cytokines? (Multiple Choice)
a. IFN-gamma and TNF alpha
b. IL-5 and TGF-beta
c. IL-10 and IFN-gamma
d. TNF alpha and IL-5
a. IFN-gamma and TNF alpha
- What are the types of parasites pictured below and their feeding characteristics?
a. Chewing lice – move rapidly on skin, feed on debris/hair
b. Sucking lice – blood feeders, closely attached to host for long periods
- What is the causative agent of Chorioptes in horses and which season is it more prevalent?
a. Chorioptes equi (aka bovis)
b. More prevalent in winter
- Describe what Rhipicephalus sanguineus looks like as an adult.
a. Vase-shaped capitulum base
b. Elongated spiracles
c. Same sized fourth coxae (compared to 1 – 3)
- List five diseases that Rhipicephalus sanguineus can be a vector for.
a. Tularemia (Francisella tularensis)
b. Ehrlichia canis
c. Babesiosis
d. Anaplasmosis
e. Tick paralysis
f. Rocky Mountain Spotted Fever
- What is the suspected mode of inheritance of juvenile demodicosis? (Multiple Choice)
a. Autosomal recessive
b. Autosomal dominant
c. Multiple methods of inherited susceptibility
a. Autosomal recessive
- What are the principle hosts of Dermacentor variabilis (immature vs adult)?
a. Immature life stages = field mouse or other small rodent
b. Adult = dog
- What are three distinguishing characteristics of Dermacentor variabilis anatomy?
a. Large fourth coxae
b. Rectangular capitulum base
c. Ornate scutum
- Distinguish how Cheyletiella and Louse ova are connected to hairs?
a. Louse eggs are firmly cemented
b. Cheyletiella eggs are attached with fine fibrillar strands
- What is the life cycle of the sarcoptic mite?
a. Eggs are laid in tunnels in the stratum corneum, then mature to larva over 2 – 3 days
b. Larvae mature to nymph stages over 3 – 4 days
c. Nymphs transition through both nymph stages over 4 – 7 days, then reach adult stage (live for 1 – 2 months on animal)
- What are five diseases that Dermacentor variabilis can be a vector for?
a. Rocky Mountain Spotted Fever
b. St. Louis encephalitis
c. Tularemia (Francisella tularensis)
d. Anaplasmosis
e. Tick paralysis
- Match the vector with the disease.
a. Rocky Mountain Spotted Fever
b. St. Louis encephalitis
c. Anaplasmosis
d. Tularemia
e. Tick paralysis
f. Ehrlichia canis
g. Babesiosis - R. sanguineus
- D. variabilis
Answers: a = 1, 2; b = 2; c = 1, 2; d = 1, 2; e = 1, 2; f = 1; g = 1
- What is the (2) etiologies of clinical signs of caprine pediculosis?
a. Irritation from biting and sucking
b. Hypersensitivity reaction to antigens in lice saliva
- True/False – The sexually reproductive and attachment stages of Otodectes mites life cycle are the same.
a. False – adults are sexually reproductive but they attach as deutonymphs
- What are the genus and species of sarcoptic mites in dogs and cats?
a. Sarcoptes scabiei (dog)
b. Notoedres cati (cat)
- What is the mechanism of tick paralysis and which type of tick (argasid or ixodid) is responsible?
a. Ixodid ticks are responsible
b. Ticks produce a protein in salivary glands or in ovaries
c. Causes ascending flaccid paralysis, attacking the lower motor neurons of spinal cord/cranial nerves, which is reversible when tick is removed
- What lifestage of Pelodera strongyloides invades the skin of dogs and humans?
a. L3 larval stages
- What are five differentials for this lesion on a horse eyelid?
Answer:
a. Habronemiasis
b. Squamous cell carcinoma
c. Bacterial or fungal granulomas
d. Equine sarcoid
e. Exuberant granulation tissue
- Match the tick-borne disease with the primary vector.
a. Anaplasma phagocytophilum
b. Borrelia burgdorferi
c. Ehrlichia ewingii/ E. chaffeensis
d. Ehrlichia canis
e. Babesia canis/conradae
f. Rocket mountain spotted fever (Rickettsia)
g. Anaplasma platys
h. Bartonella - Dermacentor variabilis
- Rhipicephalus sanguineus
- Ixodes scapularis/I. pacificus
- Amblyomma americanum
Answer: a = 3, b = 3, c = 4, d = 2, e = 2, f = 1, 2; g = 1, 2; h = 2
- What are the top three clinical signs of fipronil toxicity in rabbits?
a. Seizures
b. Anorexia
c. Lethargy
- Where are Onchocerca species found around the world?
a. O. gutturosa = N. America, Africa, Australia, Europe
b. O. reticulata = Europe and Asia
c. O. cervicalis = worldwide
- What are the lesions found in goats with warbles?
a. Numerous SC nodules and cysts with a central pore on the back and flanks
- How do chigger larvae eat?
a. Salivary secretions from the mites contain proteolytic enzymes that help the larvae feed from host tissue fluids
- For which tick (Rhipicephalus or Dermacentor) does it make sense to treat the outdoors primarily, versus treating inside the house with environmental pesticides?
a. Rhipicephalus = indoors
b. Dermacentor = outdoors
- Give four differentials for these lesions in a cat.
Answer:
a. Demodicosis
b. Pemphigus foliaceus
c. Self-trauma/barbering due to allergy
d. Notoedres infestation
- What are the clinical signs of Dermanyssus gallinae mite infestation in dogs?
a. Erythema and papulocrustous, intensely pruritic eruptions on the back and extremities
- Where do Lynxacarus radovsky mites occur in the world? (3 places)
a. Australia
b. Hawaii, Florida, Texas
c. Brazil
- How long is the Otodectes cynotis life cycle?
a. 3 weeks
- Which of the following breeds are predisposed to developing generalized demodicosis? (Multiple Choice)
a. American Staffordshire terrier, Staffordshire bull terrier, Chinese shar‐pei and French bulldog
b. Chinese shar-pei, Dalmatian, West Highland White terrier and Chihuahuas
c. American Staffordshire terrier, German Shepherd dog, King Charles Cavalier Spaniel
d. French Bulldog, English Bulldog, Pembroke Welsh Corgi and Labrador Retriever
a. American Staffordshire terrier, Staffordshire bull terrier, Chinese shar‐pei and French bulldog
- Give 3 differentials for a dog with this lesion and a history of lying outdoors on moist ground regularly.
Answer:
a. Strongyloides stercoralis
b. Ancylostoma caninum
c. Uncinaria stenocephala
d. Pelodera strongyloides
- What are four treatment options for Otodectes cynotis infestation?
a. Ivermectin PO
b. Selamectin or moxidectin.imidacloprid topical
c. Isoxazolines
d. Fipronil spot on
e. Mineral oil topical in ears (smothers mites)
- Identify which photograph is of a louse egg and which is a Cheyletiella egg.
Answer:
a = louse egg, vertical attachment with cementing substance
b = Cheyletiella egg, horizontal attachment with fine fibrils
- What clinical signs does Boophilus microplus cause in horses?
a. Hypersensitivity reactions within 30 minutes (papules and wheals)
- Where does Psoroptic mange tend to occur in cattle in the US?
a. Beef cattle on range in Western, SW, and Central states
- Give three parasitic differentials for this presentation in a rabbit.
Answer:
a. Leporacarus gibbus
b. Cheyletiella parasitovorax
c. Sarcoptes scabiei
- Describe outdoor control measures to prevent tick infestation.
a. Cut and burn brush/grass
b. Treat area in spring and midsummer with approved pesticides
- What is the drug class and mechanism of action of flumethrin?
a. Synthetic pyrethroid
b. Blocks closure of sodium channels during repolarization, causing spontaneous depolarization and hyperactivity paralysis
- Give three characteristics distinguishing mites from ticks.
a. Smaller, no leathery coating
b. Hypostome is unarmed
c. Mites have spiracles on the fused head/thorax (called the cephalothorax)
- What types of horses are predisposed to chorioptic mange?
a. Draft horses and feathered horses
- What are the clinical signs of Culicoides gnat hypersensitivity?
a. Animals that are not hypersensitive may have mild reactions
b. Topline and ventrum are commonly affected with painful, pruritic, papules and wheals
c. Mane and tail rubbing
- What are the two clinical forms of sarcoptic mange in pigs?
a. Hypersensitivity/allergic form – usually in young pigs
i. Papules, crusts, excoriations, hematomas
b. Hyperkeratotic or chronic form
i. Thick asbestos-like crusts on head, ears, neck, distal legs with moderate to intense pruritus
- What is the life cycle of the Culicoides gnat?
a. Females lay 100 to 200 eggs in the environment, which hatch within 2 – 10 days into larvae
b. Larvae moult four times (instar I to IV)
c. Fourth larval instars moult to nymphs, which pupate for 2 – 3 days and become adults
d. Adults live for 20 days
e. Transition from egg to adult takes as little as 15 days under ideal circumstances
- What are predisposed body sites for Chorioptes bovis in horses? What are typical clinical signs?
a. Distal extremities and tail base
b. Variable pruritus, erythema, crusts and scales; moist or bleeding dermatitis in more severe cases
- What three demodex species are present in canine demodicosis?
a. D. canis
b. D. injai
c. D. cornei
- What is the etiology of Norwegian or crusted scabies in dogs?
a. Immunosuppressive disease or medication
- What is the mechanism of action of isoxazolines? (Multiple Choice)
a. Enhancing chloride permeability and enhancing release of gamma amino butyric acid (GABA) at presynaptic neurons, causing paralysis of parasites
b. Inhibits GABA- and glutamate-gated chloride channels, causing uncontrolled neuronal activity with resultant paralysis
c. Acts as a nicotinic acetylcholine D-alpha receptor agonist, causing involuntary muscle contractions and tremors
d. Mimics flea juvenile growth hormone, halting development, and concentrates in female flea ovaries, causing non-viable eggs
b. Inhibits GABA- and glutamate-gated chloride channels, causing uncontrolled neuronal activity with resultant paralysis
- Match the mite with the photo.
a. D. canis
b. D. injai
c. D. cornei
Answer: a = 3, b = 1, c = 2
- Where are demodex mites located on the dog?
a. Within the hair follicles +/- in the sebaceous glands (D. injai only)
- Where do Pneumonyssoides caninum mites live?
a. Nasal passages and sinuses (nasal mite)
- Where is selamectin secreted after systemic absorption?
a. Sebaceous glands
- True/False – Lyxacardus radovsky mites have terminal suckers on all their legs.
a. True