Exam 1 Flashcards
Ectoparasite Vs Endoparasite
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
Indirect Vs Direct Lifecycle
Direct
• No intermediate host required
Indirect
• Intermediate host required
Define: reservoir, definitive, intermediate, paratenic host
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
Prepatant & Incubation Period
Prepatent period
• the time from infection until parasite sexually matures (and produces eggs)
Incubation period
• the time from infection until clinical signs appear
Basics of Arthropods
- invertebrates
- Chitinous exoskeletons
- Segmented body
- Jointed limbs
Insect Species Vs Arachnids
Insects
o Flies
o Fleas
o Lice
Arachnids (8 legs)
o Mites
o Ticks
5 Types of Mouthparts
None
• Bot flies
Piercing & sucking
• Mosquitos
• Ticks
• Lice
Sponging
• House flies
Cutting & sponging
• Horse flies
Chewing
• Lice
Tick Mouthparts
Chelicerae
• Cut into skin
Hypostome:
• Used to suck blood/insert salivary proteins, barbed for firm attachment to flesh
3 Arthropod Lifecycles
Complete metamorphosis
• Flies & fleas
• Egg -> larvae -> pupa -> adult
Incomplete metamorphosis of lice
• Egg -> nymph -> adult
Incomplete metamorphosis of mites & ticks
• Egg -> larva -> nymph -> adult
Direct & Indirect Effects of Arthropods on Hosts
Direct • Dermatitis • Blood loss • Toxicity • Myiasis (fly strike; larva inplant) • Worry
Indirect
• Secondary bacterial infections
• Transmission of disease
Pyrethrins
- Toxic to cats
* Good against most arthropods
Macrocyclic Lactones
- Good for external & internal parasites
- Has residual activity
- Approved in lactating dairy cows
- Toxic to MDR-1 mutant animals
Organophosphates
- Used on large animals
* Good for most arthropods
Neonicotinoids
- Very good for fleas
- No residual activity
- Quick acting
Fipronil
- Toxic to rabbits
* Fleas ticks mites etc
Isoxazoline
• Monthly oral
Insect Growth Regulator Drugs
- Most safe category of flea drug
* 3 types
Basics of Blowflies
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
Blowfly Myiasis
- 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
Cycle of Blowfly Myiasis in Sheep
- 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
Treatment for Blowfly myiasis; basics & specific in sheep & dogs
- 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
Prevention for Blowfly Myiasis
- Sanitation environment and animal
- Crutch and dock sheep
- Treat primary causes of diarrhea
- Insecticides or screens
Basics of Screwworms
- type of blowfly
- Cochliomyia hominivorax
- Obligate
- Eats living tissue
- Reportable exotic dz
- 2wk lifecycle
Cycle of Screwworm Myiasis
- Larvae feed on the healthy tissue in and around the wound ->
- Massive tissue destruction ->
- Secondary blowfly strike ->
- Bacterial infection ->
- Death
Treatment for Screwworms
- Contact state vet
- clip and clean the wound
- Apply insecticide
Basics of Bot Flies
o No mouth parts
o Only reproduce
o Obligate parasites
o Need specific species
Specific Bot flies for cows, sheep, horses, rodents, dogs, cats
Hypoderma sp
• cows
Oestrus ovis
• sheep
Gastrophilus sp
• horse
Cuterebra
• rodents, dogs, cats
Basic Lifecycle of Bot flies
- Egg -> larva -> pupa -> adult
* 1 generation per year
Hypoderma Sp. Lifecycle
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
Hypoderma Sp. Effects on host
- Worry & weightloss
* Meat and hide damage
Hypoderma Sp. Treatment
- Macrocyclic lactones like ivermectin
- Must treat as close to Fall as possible
- Do not treat after January due to severe immune response
Oestrus ovis (Sheep Bot Fly) LifeCycle
- Eggs hatch in adult fly ->
- Live larvae squirted directly onto sheep nose ->
- Larva live in nasal passage ->
- Larva drop into environment to pupate ->
- adult
Oestrus ovis effects on host, diagnosis, treatment
Effects on host
• Minor to no mucosal irritation
Diagnosis
• Direct observation of
Treatment
• Macrocyclic lactones in the fall
Gastrophilus Life Cycle (Horse Bot Fly)
- 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
Gastrophilus (Horse Bot Fly) Effects on host, Diagnosis, Treatment
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
Cuterebra (Rodent bot fly) Life Cycle
- 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
Cuterebra (Rodent bot fly) Effects on host, Diagnosis, Treatment
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
Species of Filth Flies
- Musca domestica- house fly
- Musca autumnalis- face fly
- Fannia scalaris- latrine fly
Filth Flies Effects on Host & Control/Prevention
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
Summer Sores
- 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
Filth Flies Dz Transmission
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
Species of Biting Flies
- Haematobia- horn fly
- Stomoxys- stable fly
- Tabanus- horse fly
Hematobia (Horn Fly); where are they seen, life cycle
• 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
Hematobia (Horn Fly) Effects on Host, Dz Transmission, Prevention/Control
Effects on Host
• Anemia
Disease Transmission
• Biological transmission of Stephanofilaria worm
Prevention & Control
• Clean poop
• Insecticides applied to animals or in feed
Stomoxys (Stable Fly); where are they found, life cycle
- 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
Stomoxys (Stable Fly); Effects on Host & Dz Transmission, prevention/control
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)
Tabanus (Horse Fly) Life Cycle
- 1 generation per year
- eggs laid in moist areas ->
- intermittent feeders not found on host
Tabanus (Horse Fly) Effects on the Host, Dz transmission, Prevention/Control
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
Melophagus (Sheep Ked); life cycle, Effects, Prevention/Control
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
Mosquitos Main Genera
- Culex,
- Aedes,
- Anopheles
Mosquito Life Cycle
- 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
Mosquito Effects on Host & Dz Transmission
Effects on Host
• Anemia
• Exsanguination
Disease Transmission
• Major dz vectors
Culicoides (Biting midge) Life Cycle
- Adaptable
- Feed @ dawn & dusk & are poor fliers
- Eggs laid in most organic material ->
- Females need blood meal to produce eggs
Culicoides (Biting midge) Dz Transmission, Effects on Host, Prevention/Control
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)
Simulium (Black flies) Life Cycle
- 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
Simulium (Black flies) Dz Transmission, Effects on Host, Prevention/Control
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
How do lice like to live
- 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
Lice Species Specific to Animal Species
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)
Lice Effects on Host
Anoplurans
• Anemia
• Hypersensitivity
Mallophagans
• Eat skin cells
• Hypersensitivity reactions
All Lice
• Hair loss
• Pruritis
Animal Susceptibility to Lice
- Nutrition
- Stress
- Crowding
- Concurrent infections
- Genetics
- Immune status
Lice Dz Transmission
• 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)
Diagnosis of Lice
- Skin inspection
- Scotch tape
- Decide species based on morphology
Treatment of Lice
- 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
Basics of Fleas
- Most important arthropod in small animal med
- Blood suckers
- No wings
- Good jumpers
- Prefer mild weather & humidity
Fleas Life Cycle
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)
Main Genera of Fleas
Ctenocephalides felis-
• dog and cat flea
Pulex-
• human flea
Xenopsylla
• rodent flea
Echidnophaga
• sticktight flea
Delete
Delete
Flea Effects on Host
o Disease transmission
o Hypersensitivity- Flea Allergy Dermatitis
o Anemia
o Rarely exsanguination
Diseases Transmitted by Fleas
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
Flea Allergy Dermatitis Basics & Lesion Distribution on Cats Vs Dogs
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
Flea Allergy Dermatitis Clinical Signs & Diagnosis
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
Flea Control: Insect Growth Regulators
• 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
Flea Control: Adulticides
• 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
Basics of Mites & Life Cycle
- 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
Species of Mites & Who They Affect
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
Basics & Life Cycle of Sarcoptes scabei
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
Transmission & Pathology of Sarcoptes scabei
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
Clinical Signs & Zoonosis of Sarcoptic Mange
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
Diagnosis of Sarcoptic Mange
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
Treatment of Sarcoptic Mange & dogs vs livestock
- 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
Notoedres; damage, diagnosis, treatment, zoonosis
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
Psoroptes sp. Basics & Hosts
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
Psoroptes sp. Transmission & Pathology
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
Psoroptes sp. Clinical Signs & Tretment for Livestock
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
Psoroptes sp. in Rabbits
- Ear canker in rabbits
- Thick crusts and scabs in inner pinna
- Stressed and immunosuppressed rabbits
- Treat with repeated subcutaneous ivermectin or moxidectin
Chorioptes sp. Basics & Transmission
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
Chorioptes sp. Clinical Signs, Diagnosis, Treatment
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
Demodex Basics
- 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
Demodex Transmission
- All puppies acquire Demodex from the dams through direct contact during nursing (normal process)
- No transmission between animals after the first acquisition
Demodex Pathology; Localized
- 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
Demodex Pathology; Generalized
- 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
Demodex Diagnosis
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
Demodex Treatment
- 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
Demodex in Cats, Cows, Sheep, Horses
• 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
Otodectes basics, transmission, zoonosis
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
Otodectes Clinical signs & Treatment
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
Cheyletiella basics, transmission, diagnosis, treatment
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
Pneumonyssoides basics, transmission, damage, diagnosis, treatment
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
2 Types of Bird Mites
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
Traits of Hard Ticks Vs Soft Ticks
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
Hard Ticks basics & Life Cycle
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
One Host Ticks Vs Three Host Ticks
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
Tick Paralysis
- 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
Order of Onset of Symptoms w/ Tick Paralysis
- Hindquateer incoordination ->
- Hindquarter paralysis ->
- Forelimb paralysis ->
- Respiratory muscle paralysis
Transstadial Vs Transovarial Dz Transmission
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
Ixodes LIFE CYCLE, Regions, Dz Transmission
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
R. sanguineus Life Cycle & Dz Transmission
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
R. annulata & R. microplus Basics
- Cattle ticks
- Eradicated from US
Tick Riders
o Patrol on horseback
o Find cows that cross from Mexico
o Check for ticks & dip cows
D. variabilis & D. andersoni; Regions, Life Cycle, Dz Transmission
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
D. albipictus Basics
- Winter tick, ghost tick, or moose tick
- Extreme hairloss & death of moose
- 1 host tick
A. americanum Basics & Dz Transmission
- Lone star tick
- 3 host tick
- lives in the East
Dz Transmission
o Cytauxzoon felis
o Tularemia
o Southern tick associated rash illness
A. maculatum Basics & Dz Transmission
- Gulf Coast Tick
- 3 host tick
- Gulf coast
Dz Transmission
o Hepatozoon americanum
Haemaphysalis longicornis Basics & Dz Transmission
- 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)
Control & Prevention of Hard Ticks
Small Animals • Selamectin • Fipronil • Deltamethrin- dogs only! • Flumethrin- safe for cats • Isoxazolines
Large Animals
• Pyrethroids- ear tags, sprays, dust
• Organophosphates
• Macrocyclic lactones
Soft Tick Species
- Otobius
* Ornithodoros
Otobius sp. Basics & Life Cycle
- 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
Otobius sp. Clinical Signs, Dz Transmission, Treatment
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
Ornithodoros sp. Basics & Dz Transmission
- soft tick
- Pajaroello Tick
- Cattle & deer
Dz Transmission
• Epizootic bovine abortion (Pajaroellobacter abortibovis)
