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Parasitology > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Ectoparasite Vs Endoparasite

A

Ectoparasites
o Live on the integument (outside) of the host and cause infestations

Endoparasites
o Live in organs and tissues inside host and cause infections

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2
Q

Indirect Vs Direct Lifecycle

A

Direct
• No intermediate host required

Indirect
• Intermediate host required

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3
Q

Define: reservoir, definitive, intermediate, paratenic host

A

Definitive host
• sexual stages occurs in this host

Intermediate host
• asexual reproduction occurs in this host

Paratenic host
• not necessary for parasite development but may help maintain the lifecycle

Reservoir
• maintains a parasite in the environment

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4
Q

Prepatant & Incubation Period

A

Prepatent period
• the time from infection until parasite sexually matures (and produces eggs)

Incubation period
• the time from infection until clinical signs appear

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5
Q

Basics of Arthropods

A
  • invertebrates
  • Chitinous exoskeletons

  • Segmented body

  • Jointed limbs
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6
Q

Insect Species Vs Arachnids

A

Insects
o Flies
o Fleas
o Lice

Arachnids (8 legs)
o Mites
o Ticks

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7
Q

5 Types of Mouthparts

A

None
• Bot flies

Piercing & sucking
• Mosquitos
• Ticks
• Lice

Sponging
• House flies

Cutting & sponging
• Horse flies

Chewing
• Lice

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8
Q

Tick Mouthparts

A

Chelicerae
• Cut into skin

Hypostome:
• Used to suck blood/insert salivary proteins, barbed for firm attachment to flesh

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9
Q

3 Arthropod Lifecycles

A

Complete metamorphosis
• Flies & fleas
• Egg -> larvae -> pupa -> adult

Incomplete metamorphosis of lice
• Egg -> nymph -> adult

Incomplete metamorphosis of mites & ticks
• Egg -> larva -> nymph -> adult

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10
Q

Direct & Indirect Effects of Arthropods on Hosts

A 
Direct
•	Dermatitis
•	Blood loss
•	Toxicity
•	Myiasis (fly strike; larva inplant)
•	Worry

Indirect
• Secondary bacterial infections
• Transmission of disease

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11
Q

Pyrethrins

A
  • Toxic to cats

* Good against most arthropods

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12
Q

Macrocyclic Lactones

A
  • Good for external & internal parasites
  • Has residual activity
  • Approved in lactating dairy cows
  • Toxic to MDR-1 mutant animals
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13
Q

Organophosphates

A
  • Used on large animals

* Good for most arthropods

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14
Q

Neonicotinoids

A
  • Very good for fleas
  • No residual activity
  • Quick acting
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15
Q

Fipronil

A
  • Toxic to rabbits

* Fleas ticks mites etc

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16
Q

Isoxazoline

A

• Monthly oral

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17
Q

Insect Growth Regulator Drugs

A
  • Most safe category of flea drug

* 3 types

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18
Q

Basics of Blowflies

A

o Genus is Lucilia
o Aka bottle flies
o metallic sheen
o Facultative myiasis
o Do not require specific host or live host
o Screwworms are exception & are obligate

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19
Q

Blowfly Myiasis

A
  • First to arrive at carcass
  • 2 week lifecycle
  • long & slender maggots
  • like warm wet smelly things (can be live animal)
  • most common in sheep but can affect rabbits, dogs, & cats
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20
Q

Cycle of Blowfly Myiasis in Sheep

A
  • Attracted to contaminated wool ->
  • Lay eggs ->
  • Larvae hatch ->
  • Larvae feed on wound exudate ->
  • Larvae secrete proteolytic enzyme to liquefy tissue -?
  • Other fly species attracted to wound ->
  • Secondary bacterial infection ->
  • Sheep stop eating -> lose weight -> die
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21
Q

Treatment for Blowfly myiasis; basics & specific in sheep & dogs

A
  • Clip and clean the area
  • remove the maggots mechanically

Sheep:

o coumaphos directly to affected region
o other organophosphates or macrocyclic lactones

Dogs:

o nitenpyram (Capstar®) orally
o insecticides- topical macrocyclic lactones, fipronil, pyrethrins

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22
Q

Prevention for Blowfly Myiasis

A
  • Sanitation environment and animal 

  • Crutch and dock 
sheep 

  • Treat primary causes of diarrhea
  • Insecticides or screens 

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23
Q

Basics of Screwworms

A
  • type of blowfly
  • Cochliomyia hominivorax
  • Obligate
  • Eats living tissue
  • Reportable exotic dz
  • 2wk lifecycle
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24
Q

Cycle of Screwworm Myiasis

A
  • Larvae feed on the healthy tissue in and around the wound ->
  • Massive tissue destruction ->
  • Secondary blowfly strike ->
  • Bacterial infection
->
  • Death
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25
Q

Treatment for Screwworms

A
  • Contact state vet
  • clip and clean the wound
  • Apply insecticide
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26
Q

Basics of Bot Flies

A

o No mouth parts
o Only reproduce
o Obligate parasites
o Need specific species

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27
Q

Specific Bot flies for cows, sheep, horses, rodents, dogs, cats

A

Hypoderma sp
• cows

Oestrus ovis
• sheep

Gastrophilus sp
• horse

Cuterebra
• rodents, dogs, cats

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28
Q

Basic Lifecycle of Bot flies

A
  • Egg -> larva -> pupa -> adult

* 1 generation per year

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29
Q

Hypoderma Sp. Lifecycle

A

June-July
o Adults lay eggs on front legs of cattle. Eggs hatch, larva penetrate skin

August – December
o Larva migrate through submucosa and grow as they migrate

January-February
o Bots accumulate around esophagus and spinal canal, and form “warbles” on the back

March-May:
o Bots fall to the ground and pupate

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30
Q

Hypoderma Sp. Effects on host

A
  • Worry & weightloss

* Meat and hide damage

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31
Q

Hypoderma Sp. Treatment

A
  • Macrocyclic lactones like ivermectin
  • Must treat as close to Fall as possible
  • Do not treat after January due to severe immune response
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32
Q

Oestrus ovis (Sheep Bot Fly) LifeCycle

A
  • Eggs hatch in adult fly ->
  • Live larvae squirted directly onto sheep nose ->
  • Larva live in nasal passage ->
  • Larva drop into environment to pupate ->
  • adult
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33
Q

Oestrus ovis effects on host, diagnosis, treatment

A

Effects on host
• Minor to no mucosal irritation

Diagnosis
• Direct observation of

Treatment
• Macrocyclic lactones in the fall

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34
Q

Gastrophilus Life Cycle (Horse Bot Fly)

A
  • 1 generation per year
  • Eggs laid on hair of forelegs ->
  • Eggs licked off of fur & migrate in oral mucosa ->
  • Larvae attach to stomach wall ->
  • Larvae pooped out to pupate in environment ->
  • adult
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35
Q

Gastrophilus (Horse Bot Fly) Effects on host, Diagnosis, Treatment

A

Effects on Host
• Usually asymptomatic
• Ulcers @ site of attachment

Diagnosis
• Confirmed by endoscopy
• Eggs on fur & larvae in mouth

Treatment
• Macrocyclic lactones in the fall

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36
Q

Cuterebra (Rodent bot fly) Life Cycle

A
  • 1 generation per year
  • eggs laid around rodent burrows ->
  • larvae penetrate body orifices & migrate to skin ->
  • larvae form warbles on skin in late spring/summer
  • larva falls off host & pupate in soil ->
  • adult
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37
Q

Cuterebra (Rodent bot fly) Effects on host, Diagnosis, Treatment

A

Effects on Host
• Can be more serious depending where larvae migrate

Diagnosis
• Find bot under the skin
• Usually forms on head or neck

Treatment
• Remove surgically w/o popping

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38
Q

Species of Filth Flies

A
  • Musca domestica- house fly
  • Musca autumnalis- face fly
  • Fannia scalaris- latrine fly
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39
Q

Filth Flies Effects on Host & Control/Prevention

A

Effects on Host
• Feed on secretions from eyes, nose, mouth
• Annoys & distracts from food intake
• Dz transmission

Control/Prevention
• Clean poop often
• Prevent flies from contacting animals (traps, blankets, etc)
• Insecticides on animals, in food, or fly bait

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40
Q

Summer Sores

A
  • Musca fly deposits larva
  • Draschia/Habronema larvae migrate in wound as long as it is moist ->
  • Pruritis and inflammatory reaction to migrating larva ->
  • non-healing sore

  • If in the eye cause conjunctivitis, leading to ulceration
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41
Q

Filth Flies Dz Transmission

A

Mechanical Bacteria Transmission
• Pink eye
• Moraxella bovis
• Corneal ulcer, conjunctivitis, pain, discharge

Biological Helminth Transmission
•	Draschia & Habronema
•	Adult flies infected w/ nematodes deposit larvae on horse ->
•	Horse ingests larva ->
•	Larva completes lifecycle ->
•	Horse isn’t harmed
•	OR
•	Larva deposited on conjunctiva or wound ->
•	Dead end for larva ->
•	Summer Sores
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42
Q

Species of Biting Flies

A
  • Haematobia- horn fly
  • Stomoxys- stable fly

  • Tabanus- horse fly
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43
Q

Hematobia (Horn Fly); where are they seen, life cycle

A

• Live on back of cows

Life Cycle
• Adult feeds on blood to produce eggs ->
• Eggs laid in manure ->
• Adults stay on host most of the time

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44
Q

Hematobia (Horn Fly) Effects on Host, Dz Transmission, Prevention/Control

A

Effects on Host
• Anemia

Disease Transmission
• Biological transmission of Stephanofilaria worm

Prevention & Control
• Clean poop
• Insecticides applied to animals or in feed

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45
Q

Stomoxys (Stable Fly); where are they found, life cycle

A
  • Lives on legs of cows
  • More than 10 on legs of cows = nearby breeding area

Life Cycle
• Adult feeds on blood to produce eggs ->
• Eggs laid in straw/hay ->
• Adults do not stay on host

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46
Q

Stomoxys (Stable Fly); Effects on Host & Dz Transmission, prevention/control

A

Effects on Host
• Irritation
• Anemia

Disease Transmission
• Mechanical of blood borne pathogens
• Biological transmission of summer sores

Prevention/Control
• Eliminate moist/decaying areas
• Insectcides applied to animal (not as effective)

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47
Q

Tabanus (Horse Fly) Life Cycle

A
  • 1 generation per year
  • eggs laid in moist areas ->
  • intermittent feeders not found on host
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48
Q

Tabanus (Horse Fly) Effects on the Host, Dz transmission, Prevention/Control

A

Effects on Host
• Painful bites
• Worry & irritation

Dz Transmission
• Mechanically blood-birne pathogens
• Biologically Elaeophora (blood vessel worm)

Prevention & Control
• Very difficult
• Drain wet areas if possible

49
Q

Melophagus (Sheep Ked); life cycle, Effects, Prevention/Control

A

Life Cycle
• Entire cycle on host
• larva hatch inside adult ->
• pupa sticks to wool

Effects on host
•	Intensely irritating
•	Excrement stains wool
•	Anemia
•	Nodules on hide

Prevention & Control
• Easily eliminated
• Shearing followed by organophosphates or pyrethrins

50
Q

Mosquitos Main Genera

A
  • Culex,
  • Aedes,
  • Anopheles
51
Q

Mosquito Life Cycle

A
  • Adaptable & weather dependent
  • Eggs laid in water or areas that flood often ->
  • Larvae (wigglers) live in water w/ breathing siphon to air ->
  • Pupa (tumblers) also live in water & need air ->
  • Adult females take blood meal & adult males live on nectar
52
Q

Mosquito Effects on Host & Dz Transmission

A

Effects on Host
• Anemia
• Exsanguination

Disease Transmission
• Major dz vectors

53
Q

Culicoides (Biting midge) Life Cycle

A
  • Adaptable
  • Feed @ dawn & dusk & are poor fliers
  • Eggs laid in most organic material ->
  • Females need blood meal to produce eggs
54
Q

Culicoides (Biting midge) Dz Transmission, Effects on Host, Prevention/Control

A

Disease Transmission
• Can transmit many dz to different species

Effects on Host
• Hypersensitivity – “sweet itch” in horses
• Alopecia, crusting, inflammation, & pruritis around tail

Prevention & Control
• Eliminate breeding areas
• Bring animals indoors @ dawn & dusk
• Permethrin stable spray (only somewhat helpful)

55
Q

Simulium (Black flies) Life Cycle

A
  • Active in daylight
  • Good fliers
  • Eggs laid in running water- >
  • Larvae attach to rocks under water
 ->
  • Pupate under water
->
  • Adults hatch and float up to surface
->
  • Adults require blood meal to produce eggs
56
Q

Simulium (Black flies) Dz Transmission, Effects on Host, Prevention/Control

A

Disease Transmission
• Onchocerca filarid worms in skin and connective tissue of horses and cattle
• Leukocytozoon hemoprotozoan similar to Malaria in birds

Damage to Host
• Hypersensitivity reactions in many species

Prevention & Control
•	Eliminate breeding areas
•	Stable animals during the day when swarms appear
•	Repellents- pyrethrins may help 
•	Fly masks & Blankets
57
Q

How do lice like to live

A
  • Need a physical bridge to move from host to host
  • Usually sedentary - remain attached to hair follicle or feather
  • Common on animals housed inside (and close together)

  • Outbreaks most common in winter when animals huddle close together
58
Q

Lice Species Specific to Animal Species

A

Dogs

• Trichodectes - chewing
• Linognathus - sucking

Cats

• Felicola - chewing

Cattle

• Haematopinus, Linognathus, and Solenopotes - sucking
• Bovicola (Damalinia) - chewing

Horses

• Damalinia - chewing

Birds
• Many species of Mallophagans

(Look at Picture in Notes)

59
Q

Lice Effects on Host

A

Anoplurans
• Anemia
• Hypersensitivity

Mallophagans
• Eat skin cells
• Hypersensitivity reactions

All Lice
• Hair loss
• Pruritis

60
Q

Animal Susceptibility to Lice

A
  • Nutrition
  • Stress
  • Crowding
  • Concurrent infections
  • Genetics
  • Immune status
61
Q

Lice Dz Transmission

A

• Poor dz vectors

Hog louse (Hematopinus suis)
•	 transmits swine pox and Mycoplasma

Canine chewing louse (Trichodectes canis)
• may be an intermediate host for the tapeworm Diplylidium caninum

Human body louse
• can transmit epidemic typhus (Rickettsia prowazekii)

62
Q

Diagnosis of Lice

A
  • Skin inspection
  • Scotch tape
  • Decide species based on morphology
63
Q

Treatment of Lice

A
  • Pour ons for chewing lice
  • Injectable for sucking lice
Dogs and cats 
•	Fipronil 

•	Imidacloprid 

•	Pyrethrins- dogs only, NOT CATS 

•	Macrocyclic lactones (require only 1 treatment)

Large animals

• Organophosphates ( 2 treatments 2wks apart)
• Macrocyclic lactones
• Pyrethrins 


64
Q

Basics of Fleas

A
  • Most important arthropod in small animal med
  • Blood suckers
  • No wings
  • Good jumpers
  • Prefer mild weather & humidity
65
Q

Fleas Life Cycle

A

o ~4-6 week cycle can be adaptable 


Eggs:
• 
Flea feces/blood deposited
with eggs

• Both usually fall off host into environment 


Larvae:
• hatch and eat flea feces 


Pupa:
• can stay in this stage for a year 


Adult:
• Flea emerges hungry and seeks host-
once on host usually stays there
(unless crowded-then it may hop to another host)

66
Q

Main Genera of Fleas

A

Ctenocephalides felis-
• dog and cat flea

Pulex-
• human flea


Xenopsylla
• rodent flea

Echidnophaga
• sticktight flea

67
Q

Delete

A

Delete

68
Q

Flea Effects on Host

A

o Disease transmission
o Hypersensitivity- Flea Allergy Dermatitis
o Anemia
o Rarely exsanguination

69
Q

Diseases Transmitted by Fleas

A

Dipylidium caninum- tapeworm
• most common tapeworm of dogs in many parts of the US
• Dogs and cats get infected by eating the flea
• Can see pieces of the tapeworm (proglottids) in feces or crawling around anus

Plague- Yersinia pestis
• transmitted by Pulex and Xenopsylla
• Maintained in cycles between wild rodents
• when the rodent dies, fleas look for another host -> may find a cat (or dog or human)

Myxomatosis- rabbit poxvirus
• mechanically transmitted by rabbit fleas and mosquitoes
• Causes conjunctivitis, blindness, skin tumors
• Can be rapidly fatal

70
Q

Flea Allergy Dermatitis Basics & Lesion Distribution on Cats Vs Dogs

A

o most common dermatologic disease of dogs in the US
o Can be caused by different types of hypersensitivity: Type I, Type IV
o and basophil hypersensitivity
o IgE and IgG develop in response to antigens in flea saliva
o Seasonal

Lesion Distribution
• Cats: miliary dermatitis on face, neck, and back
• Dogs: lower back, tailhead, caudal/inner thighs

71
Q

Flea Allergy Dermatitis Clinical Signs & Diagnosis

A

Clinical Signs
• Alopecia: hair loss
• Erythema: skin reddening

• Pruritis: intense itching results in self trauma

• Acanthosis and hyperkeratosis: thickening of skin
• Seborrhea: red, scaly skin
• Secondary bacterial infections

Diagnosis
• Intradermal Skin Test
• Immediate reaction in 15-20 mins
• May have delayed reaction @ ~24hr

72
Q

Flea Control: Insect Growth Regulators

A

• Do not kill insects but prevent them from reaching maturity or reproducing

Lufenuron
• monthly oral chews
• Stored in animals body fat
• fleas ingest it while feeding and transfer to the egg
• Prevents formation of chitin
• egg fails to hatch or larvae cannot molt

Methoprene
• topical spot-on
• Juvenile hormone mimicker
• prevents pupa from maturing

Pyriproxyfen
• Juvenile hormone mimicker
• inhibits egg development, and prevents molts

73
Q

Flea Control: Adulticides

A

• Kill adults directly (and sometimes larvae too)

Imidacloprid (Neonicotinoid)
• topical

Nitenpyram (Neonicotinoid)
• rapid oral


Spinosad (Neonicotinoid)
• monthly oral


Dinotefuran (Neonicotinoid)
• topical

Fipronil
• topical

Selamectin (Macrocyclic lactones)
• topical

Indoxacarb
• topical

Isoxazolines
• Monthly chewables

Pyrethrins
• Topical for dogs ONLY

74
Q

Basics of Mites & Life Cycle

A
  • Microscopic- usually < 0.5 mm 

  • Smooth hypostome to pierce skin and suck 
blood 

  • Short life cycle (<1 month) 

  • Cause “mange” 

  • Some burrow deeply into skin and/or hair follicles, and some live superficially within keratin 


Life Cycle
o Incomplete metamorphosis (no pupa)
o A molt occurs between each stage

75
Q

Species of Mites & Who They Affect

A

Sarcoptes scabiei
• pruritic dermatitis of many domestic animals

Notoedres
• similar to Sarcoptes but on cats

Psoroptes
• scabby lesions of large animals and rabbits
• long segmented pedicel

Chorioptes
• mild flaky dermatitis of large animals
• very short pedicel

Demodex
• normal flora of most species- can be severe in dogs

Otodectes
• ear mite of dogs and cats

Pneumonyssoides
• nasal mite of dogs

Dermanyssus, Ornithonyssus, Knemidocoptes
• birds

76
Q

Basics & Life Cycle of Sarcoptes scabei

A

o long strait pedicel
o host specific
o cats & guinea pigs NOT susceptible

Life Cycle
• Whole life cycle occurs on host
• Adults burrow deep in the skin
• Eggs are laid in the burrows that the adults make
• Larva and nymphs look like adults but smaller

77
Q

Transmission & Pathology of Sarcoptes scabei

A

Transmission
• Primarily by direct contact
• Transmission from bedding is possible (live 48-72hrs off host)

Pathology
• Dermatitis caused by damage and inflammation produced by burrowing mites

78
Q

Clinical Signs & Zoonosis of Sarcoptic Mange

A 
Clinical Signs
•	Intense pruritis 
•	Self-mutilation 
•	Hair loss

•	Weight loss 
•	Secondary bacterial infections


Zoonosis
• Can transmit from animals to homans
• Infection is transient & self limiting

79
Q

Diagnosis of Sarcoptic Mange

A

Skin scrape
o Can be difficult to find
o Sample crusty ear margins or elbows/hocks

Skin biopsies (if scrapes are negative)
o	Low sensitivity- take multiple punch biopsies

Pinnal-pedal reflex
o Gently scratching on ear pinna causes animal to lift rear leg to scratch –> presumptive diagnosis

80
Q

Treatment of Sarcoptic Mange & dogs vs livestock

A
  • Treat even if all tests negative
  • Clean and clip affected areas and remove crusts (repeat several times over weeks)
  • Treat all animals in contact

Dogs:
o Topical Selamectin
o Topical Moxidectin + Imidacloprid

Livestock
o Reportable
o Topical eprinomectin in dairy cattle
o Ivermectin in other cows

81
Q

Notoedres; damage, diagnosis, treatment, zoonosis

A

o Rare cause of mange in cats, rats, rabbits

Damage to host
• Dermatitis starting on medial edge of pinna
• Ears -> face -> paws -> hindquarters

Diagnosis
• Skin scrape

Treatment
• topical selamectin,
• ivermectin,
• weekly lime sulfur dips x 6

Zoonosis
• Self-limiting in humans

82
Q

Psoroptes sp. Basics & Hosts

A

o Species specific
o Does not burrow
o Whole life cycle on host but can survive off host for a couple of weeks
o Reportable in livestock

Hosts
• Cows, horses, sheep, camelids, rabbits

83
Q

Psoroptes sp. Transmission & Pathology

A

Transmission
• Direct Contact
• Indirect contact: Brushes, combs, tack etc.
• Environment
• Asymptomatic carriers can transmit to others in the group

Pathology
• Pierces skin with pointed mouthparts -> serum exudation and scab formation
• Hypersensitivity reaction to mite feces produces crusts & intense pruritis
• Scabs become confluent and mites move on to fresh areas

84
Q

Psoroptes sp. Clinical Signs & Tretment for Livestock

A

Clinical Signs
• Yellowish scaly crusty lesions starting at the 
shoulders and neck

• In sheep, wool falls out in tufts 

• Pruritis
• Decreased appetite, weight loss, anemia, and secondary bacterial infections 

• Rapidly fatal in lambs 


Treatment in Livestock
• Clean and clip

• Macrocyclic lactones, organophosphates, pyrethrins
• Must treat environment or vacate pasture 2-4 weeks to prevent reinfestation

85
Q

Psoroptes sp. in Rabbits

A
  • Ear canker in rabbits
  • Thick crusts and scabs in inner pinna

  • Stressed and immunosuppressed rabbits
  • Treat with repeated subcutaneous ivermectin or moxidectin
86
Q

Chorioptes sp. Basics & Transmission

A 
o	Barn itch or leg mange
o	Most common mange mite on horses and 
o	Tail, hind legs of cattle and horses 
o	Forelegs of sheep, goats, camelids 
o	non burrowing
o	adults only live few days on host

Transmission
• Direct contact
• Indirect contact
• No environmental contamination

87
Q

Chorioptes sp. Clinical Signs, Diagnosis, Treatment

A

Clinical Signs
• Often asymptomatic
• Mild, flaky dermatitis on legs and pelvic region
• Nonpruritic to mildly pruritic
• Seen when animals are kept inside (especially in winter)
• Tends to disappear when animals are let out in spring

Diagnosis
• Superficial skin scrape

Treatment
• Clean and clip

• Macrocyclic lactones, organophosphates, pyrethrins

88
Q

Demodex Basics

A
  • All stages live in the epidermis and hair follicles of most animals
  • Part of normal skin flora (small numbers are present in healthy dogs)
  • Eats skin cells and oils

  • Species Specific
89
Q

Demodex Transmission

A
  • All puppies acquire Demodex from the dams through direct contact during nursing (normal process)
  • No transmission between animals after the first acquisition
90
Q

Demodex Pathology; Localized

A
  • Localized alopecia- around eyes, mouth, and bony projections
  • Usually puppies less than 6 months, but can occur in older dogs
  • 90% resolves with sexual maturity
  • Does NOT require treatment
91
Q

Demodex Pathology; Generalized

A
  • Defect in cell mediated immunity due 
to underlying disease/condition 

  • juvenile or adult dogs 

  • Large area of body affected 

  • generalized alopecia, thickened skin, erythema
  • Nonpruritic 

  • Disagreeable odor 

  • Secondary staphylococcal bacterial infections are inevitable
92
Q

Demodex Diagnosis

A

Deep skin scrape

Skin biopsy
• hair follicles containing 1 to many mites
• low sensitivity

Trichogram
• Pull entire hair including root & put on oil slide

Fecal Float
• Dogs groom & swallow demodex
• Mites float in fecal float

93
Q

Demodex Treatment

A
  • Treat possible underlying causes
  • Amitraz is the only FDA-approved treatment for generalized demodicosis (not available anymore)
  • Isoxazolines extralabel for several months
  • High dose macrocyclic lactones
  • Always treat generalized w/ antibiotics
94
Q

Demodex in Cats, Cows, Sheep, Horses

A

• Usually not treated

Cats
• can cause dermatitis around head

Cattle
• pustular dermatitis on neck

• Extruded exudate contains many mites!

Sheep and goats
• nodular dermatitis of neck and udder
• Usually cannot extrude purulent material

Horses
• alopecia around eyes and face

95
Q

Otodectes basics, transmission, zoonosis

A

o External ear canal of dogs, cats, ferrets
o Sometimes on head, neck, back
o Very short pedicel
o Does not burrow

Transmission
• Direct contact (usually from mom)

Zoonosis
• Spreads to humans who sleep in same bed as animal

96
Q

Otodectes Clinical signs & Treatment

A 
Clinical Signs
•	Can cause hypersensitivity
•	Intense pruritis -> self inflicted ear damage 

•	Copious dark brown ear wax 

•	sandy, flaky debris 
•	Secondary infection 
•	Left untreated, can cause permanent ear damage 

•	Can cause a generalized dermatitis 


Treatment
• Clean debris out of ear
• Systemic selamectin and imidacloprid
• Topical medicated ear solutionsw/ acaricide like milbemycin

97
Q

Cheyletiella basics, transmission, diagnosis, treatment

A

o “walking dandruff”
o exfoliative, flaky dermatitis

Transmission
• Survive a long time off the host
• very mobile
• very contagious 


Diagnosis
• Put patient on a dark surface and look for moving white specks
• Flea comb, hair plucks and tape impressions to recover mites for microscopic exam
• Cats- may be able to demonstrate on fecal float

Treatment
• none are approved

• may use topical selamectin or other

98
Q

Pneumonyssoides basics, transmission, damage, diagnosis, treatment

A

o mite in nasal passages and sinuses of dogs and cats 


Transmission
• Highly mobile, easily transmitted by direct contact 


Damage to host
• Irritation, nasal discharge, sneezing, reverse sneezing 


Diagnosis
• seen in nasal secretions and external nares 


Treatment
• Subcutaneous ivermectin or milbemycin

99
Q

2 Types of Bird Mites

A

Blood feeding mites
• Can accumulate to high numbers, cause anemia, kill nestlings, reduce egg production
• Dermanyssus: Found in the nest 

• Ornithonyssus: Remains on the bird 


Scaly Leg and Scaly Face mites 

• Knemidocoptes - Burrows under scales and deforms feet and face 


100
Q

Traits of Hard Ticks Vs Soft Ticks

A 
Hard
•	Anterior mouthparts 
•	Smooth, waxy body surface

•	Larva, nymph and adult feed only once
•	Female lays huge batch of eggs once and dies 
•	Live mostly on host

Soft
• Ventral mouthparts
• Rough, spiny body parts
• Nymphs & adults take many short blood meals
• Female feeds many times & lays small batch eggs after each meal
• Live in nesting/bedding area

101
Q

Hard Ticks basics & Life Cycle

A

o Engorged vs not engorged females

Life Cycle
• Female lays eggs in environment 
->
• Larval hatch out and “quest” for host, and hop on 
->
• Larva get a blood meal from their host & then molt into nymphs 
->
• Nymphs take blood meal from host and molt into adults 
->
• Adults take blood meal & female becomes massively engorged and falls off host 
->
• Female lays eggs & dies

102
Q

One Host Ticks Vs Three Host Ticks

A

One Host ticks
• tick remains on the host through all life cycle stages until the female falls off to lay her eggs

Three Host Ticks (most common in US)
• Each life cycle stage finds a new host to take a meal from
• Molting and egg laying occur in the environment

103
Q

Tick Paralysis

A
  • Most commonly caused by Dermacentor
  • Most common in PNW
  • Tick saliva can contain a neurotoxin that causes an ascending paralysis
  • larger the animal the more ticks are needed to result in paralysis
  • 1 tick can produce paralysis in small animals, small humans
  • Llamas and alpacas are particularly susceptible

  • Usually heavy infestations are required to cause paralysis in cattle
  • Recover rapidly after tick removal
104
Q

Order of Onset of Symptoms w/ Tick Paralysis

A
  • Hindquateer incoordination ->
  • Hindquarter paralysis ->
  • Forelimb paralysis ->
  • Respiratory muscle paralysis
105
Q

Transstadial Vs Transovarial Dz Transmission

A

Transstadial
• one life cycle stage picks up the disease from an infected host ->
• transmits dz to the next host after molting

Transovarial
• adult tick transmits pathogens to her eggs ->
• disease is maintained between generations

106
Q

Ixodes LIFE CYCLE, Regions, Dz Transmission

A

Life Cycle
• Use rodents while larva
• Use huamns & dogs as nymphs
• Use deer as adults

Dz Transmission
• Both species lime disease & anaplasma phagocytophillum
• i. scapularis transmits Babesia microti

Regions
• I scapularis : East Coast
• I. pacificus: West Coast

107
Q

R. sanguineus Life Cycle & Dz Transmission

A 
Life Cycle
o	3 host tick
o	prefer tropical regions
o	can complete entire life indoors
o	can live 1 year off host

Dz Transmission
o Ehrlichia canis
o Babesia canis

108
Q

R. annulata & R. microplus Basics

A
  • Cattle ticks
  • Eradicated from US

Tick Riders
o Patrol on horseback
o Find cows that cross from Mexico
o Check for ticks & dip cows

109
Q

D. variabilis & D. andersoni; Regions, Life Cycle, Dz Transmission

A

Regions
• D. variabilis - East & California
• D. andersoni - North West (but not coast)

Life Cycle
• 3 host tick

Dz Transmission
• Rickettsia rickettsia (Rocky Mountain Spotted Fever)
• Tularemia

• Anaplasma marginale

110
Q

D. albipictus Basics

A
  • Winter tick, ghost tick, or moose tick
  • Extreme hairloss & death of moose
  • 1 host tick
111
Q

A. americanum Basics & Dz Transmission

A
  • Lone star tick
  • 3 host tick
  • lives in the East

Dz Transmission
o Cytauxzoon felis
o Tularemia
o Southern tick associated rash illness

112
Q

A. maculatum Basics & Dz Transmission

A
  • Gulf Coast Tick
  • 3 host tick
  • Gulf coast

Dz Transmission
o Hepatozoon americanum

113
Q

Haemaphysalis longicornis Basics & Dz Transmission

A
  • Asian Long-horned Tick
  • Came from Asia
  • does not need male to reproduce
  • VERY invasive & now in 15 states

Dz Transmission
• Theileria orientalis (bovine infectious anemia)

114
Q

Control & Prevention of Hard Ticks

A 
Small Animals
•	Selamectin

•	Fipronil

•	Deltamethrin- dogs only! 
•	Flumethrin- safe for cats 
•	Isoxazolines

Large Animals
• Pyrethroids- ear tags, sprays, dust
• Organophosphates
• Macrocyclic lactones

115
Q

Soft Tick Species

A
  • Otobius

* Ornithodoros

116
Q

Otobius sp. Basics & Life Cycle

A
  • soft tick
  • Spinose Ear Tick
  • Borad host range
  • Southwestern US
Life Cycle
•	Free living adults lay eggs in soil ->
•	Larvae climb on animal & into ear ->
•	Larvae molt to nymph in ear ->
•	Nymphs drop to ground & molt to adult
117
Q

Otobius sp. Clinical Signs, Dz Transmission, Treatment

A

Clinical Signs
• Irritation due to painful bites
• Secondary ear infections
• Encephalitis

Dz Transmission
• Q fever (Coxiella burnetti)

Treatment
• any drug that kills hard ticks applied in ear

118
Q

Ornithodoros sp. Basics & Dz Transmission

A
  • soft tick
  • Pajaroello Tick
  • Cattle & deer

Dz Transmission
• Epizootic bovine abortion (Pajaroellobacter abortibovis)

Parasitology (4 decks)

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