Ectoparasites

The ArthropodsThe Arthropods

PhylumArthropoda

ClassInsecta

ClassArachnida

ClassPentastomida

Class insecta Class insecta

ClassInsecta

OrderDiptera(flies)

OrderPhthiraptera

(lice)

OrderSiphonaptera

(fleas)

ClassClassArachnidaArachnida

Ticks and mites are small Ticks and mites are small arachnids in the arachnids in the Order AcarinaOrder Acarina. . Many are parasitic on animals Many are parasitic on animals and humans, & vary greatly and humans, & vary greatly between families.between families.

Class Pentastomida (“tongue Class Pentastomida (“tongue worms”)worms”)

Very unusual insects, may be Very unusual insects, may be related to sarcoptiform mites or related to sarcoptiform mites or to annelids (earthworms).to annelids (earthworms).

Parasite Species Agent Parasite Species Agent DiseaseDisease

ParasiteParasite SpeciesSpecies AgentAgent DiseaseDisease

MosquitoeMosquitoess

CulicoidesCulicoides

MitesMites

FliesFlies

HorseHorse VirusVirus

VirusVirus

VirusVirus

CestodeCestode

NematodeNematode

WNVWNV

WEE; EEE; WEE; EEE; VEEVEE

EIAEIA

TapewormsTapeworms

Summer Summer sores sores (habronem(habronema)a)

VirusVirus EIAEIA

Bot fly Bot fly Female bot flies lay Female bot flies lay

from 150 to 1,000 from 150 to 1,000 yellowish eggs. The yellowish eggs. The eggs are firmly glued eggs are firmly glued to the hairs of the to the hairs of the forelegs, belly, forelegs, belly, flanks, shoulders and flanks, shoulders and other parts of the other parts of the body of the horse. body of the horse. While the fly's egg While the fly's egg laying does not laying does not cause the horse cause the horse pain, the horse often pain, the horse often is bothered by is bothered by presence of the fly.presence of the fly.

Bee-like adult

Bot fliesBot flies

• • Does not bite; may Does not bite; may botherbother

• • Eggs on legsEggs on legs• • Licked by horseLicked by horse• • 4 weeks in oral mucosa4 weeks in oral mucosa• • Overwinter in stomachOverwinter in stomach• • UlcersUlcers• • Control:Control:– – External: insecticide on External: insecticide on

legslegs– – Internal: broad spectrumInternal: broad spectrumanthelminticsanthelmintics

Horse and deer fliesHorse and deer flies

• • LargeLarge• • Multiple speciesMultiple species• • Females only biteFemales only bite• • Generally: larvae in water orGenerally: larvae in water ordamp locationsdamp locations• • Strong flyersStrong flyers• • Daytime feedersDaytime feeders• • Painful bitesPainful bites– – Horse flies: anti-coagulantHorse flies: anti-coagulant– – Secondary infectionsSecondary infections– – Transmission of disease:Transmission of disease:• • EIAEIA• • AnaplasmosisAnaplasmosis• • Larvae – not possibleLarvae – not possible• • Adults – fly repellantsAdults – fly repellants

Stable fliesStable flies

• • Both males and femalesBoth males and females• • Around premisesAround premises• • Strong flyersStrong flyers• • Painful bitesPainful bites• • Soggy hay/manure haySoggy hay/manure hay• • TransmitTransmit– – EIAEIA– – HabronemaHabronema• • Identify and controlIdentify and controlbreeding site(s)breeding site(s)• • Insect repellantsInsect repellants

Summer sores (habronemiasis)Summer sores (habronemiasis)

• • Caused by the larva of Caused by the larva of nematode species;nematode species;Habronema muscaeHabronema muscaeHabronema majusHabronema majus

• • Stomach-dwellingStomach-dwelling• • Indirect life cycleIndirect life cycle• • Fly-transmittedFly-transmitted• • SeasonalSeasonal• • Hypersensitivity componentHypersensitivity component• “• “Aberrant parasitism” whenAberrant parasitism” whenlarvae deposited in woundslarvae deposited in wounds• • Esp. eyes, conjunctiva, maleEsp. eyes, conjunctiva, malegenitalia, distal limbsgenitalia, distal limbs• • Prevent - ivermectinPrevent - ivermectin

Culicoide Hypersensitivity Culicoide Hypersensitivity ( Queensland itch, Sweet itch, ( Queensland itch, Sweet itch,

Summer itch)Summer itch)

Culicoides Culicoides hypersensitivityhypersensitivity

• “• “Sweet itch”Sweet itch”

• • Individual horsesIndividual horses

• • Acute Acute hypersensitivityhypersensitivity

• • Spring-summerSpring-summer

• • Regresses in fall-Regresses in fall-winterwinter

• • Tail, rump, back, Tail, rump, back, witherswithers

No-See-UmsNo-See-Ums

• • Culicoides & sandfliesCulicoides & sandflies

• • Need aquatic habitatsNeed aquatic habitats

• • Allergic reactions inAllergic reactions in

horseshorses

• • Also:Also:

– – BTV BTV bluetongue virusbluetongue virus – – EHD EHD epizootic hemorrhagic epizootic hemorrhagic

disease disease

– – EIAEIA

MosquitoesMosquitoes

• • Wet sitesWet sites• • Only females feedOnly females feed• • Still waterStill water• • 6 – 7 days to complete life6 – 7 days to complete lifecyclecycle• • Day or night feedersDay or night feeders• • Variable year to year,Variable year to year,depending on moisturedepending on moisture• • Many speciesMany species• • Diseases:Diseases:– – WEEWEE– – EEEEEE– – WNVWNV– – VEEVEE

Mosquito controlMosquito control

• • Control large wet breeding Control large wet breeding sitessites

– – Pest control districtsPest control districts• • Keep water containers to Keep water containers to

minimum:minimum:– – Empty troughs every ~3 Empty troughs every ~3

daysdays• • Bacillus thuringensis (BT) Bacillus thuringensis (BT)

dunksdunks• • Screen water containersScreen water containers• • Stable horses dawn and Stable horses dawn and

duskdusk• • Insect zappers relatively Insect zappers relatively

ineffectiveineffective• • Topic sprays for horsesTopic sprays for horses

Topical anti-mosquito productsTopical anti-mosquito products

• • Pyrethrins - chrysanthemum extractPyrethrins - chrysanthemum extract– – Effective; short durationEffective; short duration• • Pyrethroids - syntheticPyrethroids - synthetic– – Low toxicity; longer-lasting than pyrethrins.Low toxicity; longer-lasting than pyrethrins.– – Permethrin and cypermethrinPermethrin and cypermethrin• • Plant extractsPlant extracts– – Citronella, eucalyptus, pennyroyal, cedar, geraniol etc.Citronella, eucalyptus, pennyroyal, cedar, geraniol etc.• • DEET (DEET (NN,,NN-Diethyl--Diethyl-metameta-toluamide-toluamide, is the most , is the most

common active ingredient in insect repellents)common active ingredient in insect repellents)– – Now EPA approved for horsesNow EPA approved for horses– – Licensed veterinarians.Licensed veterinarians.– – Repellent only - not insecticidalRepellent only - not insecticidal

Blowflies andBlowflies andfleshfliesfleshflies

• • 60 species60 species• • Cadavers and woundsCadavers and wounds• • Eggs in moist wool,Eggs in moist wool,open wounds or breakopen wounds or breakin the skinin the skin• • Rare in cattle or horses.Rare in cattle or horses.• • Painful – can be fatalPainful – can be fatal• • Prevent by properPrevent by proper insecticide treatments.insecticide treatments.• • Treat with insecticideTreat with insecticideapplicationsapplications

ScrewwormScrewworm

• • New World speciesNew World species• • Infects live warm blooded Infects live warm blooded

speciesspecies• • Infects peopleInfects people• • Open wounds and healthy Open wounds and healthy

tissuetissue• • Eradicated in USEradicated in US• • Esp. newbornsEsp. newborns• • High mortality when High mortality when

untreateduntreated• • Latin AmericaLatin America• • Controlled by sterile male Controlled by sterile male

releaserelease• • Reportable to USDAReportable to USDA• • Periodic incursions to USAPeriodic incursions to USA

Horn fliesHorn flies

• • Blood suckersBlood suckers• • Eggs in fresh manure (<10 Eggs in fresh manure (<10

min)min)• • Consume 10μl blood dailyConsume 10μl blood daily– – 3000/cow=30 ml/day3000/cow=30 ml/day• • Rapid life cycle (10 days)Rapid life cycle (10 days)• • Strong flyersStrong flyers• • Live on cattleLive on cattle• • Nuisance:Nuisance:– – CattleCattle– – HorsesHorses• • Insecticidal ear tagsInsecticidal ear tags– – On host a lotOn host a lot• • Dragging pastures to break Dragging pastures to break

up fecesup feces

Acute hypersensitivity Acute hypersensitivity reactions in horsereactions in horse

Acute hypersensitivity Acute hypersensitivity reactions in horsereactions in horse

Lice • Sucking – bloodLice • Sucking – blood

• • Biting – surface debrisBiting – surface debris• • Location specificLocation specific• • Whole life on hostWhole life on host• • WinterWinter• • Attack all ages esp.Attack all ages esp.• • Head, neck, shoulders,Head, neck, shoulders,and rumpand rump• • Irritate skinIrritate skin• • Control in fallControl in fall• • Pour-on formulations –Pour-on formulations –treat twice 3 weeks aparttreat twice 3 weeks apart*Zoonotic *Zoonotic

Mange mitesMange mites

• • Now uncommonNow uncommon• • Burrow in skinBurrow in skin• • Dermatitis andDermatitis andhypersensitivityhypersensitivityreactionsreactions• • Transmission by:Transmission by:– – Direct contactDirect contact– – Fomites Fomites • • IvermectinIvermectin• • Decontaminate stablesDecontaminate stablesand grooming equipmentand grooming equipment

Demodectic MitesDemodectic Mites

The demodectic or The demodectic or follicular mite is a follicular mite is a microscopic (0.23mm), microscopic (0.23mm), cigar shaped worm-like cigar shaped worm-like mite that lives within the mite that lives within the skin. skin.

All stages of the life cycle All stages of the life cycle are often found within are often found within the hair follicle and the hair follicle and sebaceous glands. sebaceous glands.

The mite causes nodular The mite causes nodular lesions in the skin usually lesions in the skin usually around the neck and around the neck and shoulders.shoulders.

Chigger MitesChigger Mites

Chigger mites Chigger mites (redbugs) make up (redbugs) make up a large group of a large group of species which species which occasionally cause occasionally cause problems for both problems for both horses and man. horses and man. They cause intense They cause intense itching and reddish itching and reddish welts on the skin.welts on the skin.

Mite ControlMite Control

Mange control requires isolation of Mange control requires isolation of infested animals and thorough wetting infested animals and thorough wetting of the whole animal with timed of the whole animal with timed applications of approved pesticides.applications of approved pesticides.

Chiggers can be controlled by Chiggers can be controlled by application of detergent wash application of detergent wash containing one of the insecticides containing one of the insecticides registered for other mites. Area registered for other mites. Area control is not feasible.control is not feasible.

TicksTicks

• • Multiple speciesMultiple species• • Seasonal activity varies:Seasonal activity varies:winter vs. summerwinter vs. summer• • Some have multiple hosts,Some have multiple hosts,depending on stagedepending on stage• • DermatitisDermatitis• • Transmission:Transmission:– – AnaplasmosisAnaplasmosis– – TularemiaTularemia– – Tick paralysisTick paralysis– – Babesiosis (horses)Babesiosis (horses)• • Topical/systemic acaricidesTopical/systemic acaricides

Spinose ear ticks feeding Spinose ear ticks feeding

External parasites horsesExternal parasites horses

Agent(s) Impact Disease Control CommentAgent(s) Impact Disease Control CommentStable flyStable flyHabronema ++ “SummerHabronema ++ “Summersores”sores”Anthelmitic SummerAnthelmitic SummerBiting midgesBiting midgesCulicoidesCulicoides++ “Sweet itch” Stabling++ “Sweet itch” StablingSteroidsSteroidsSummerSummerFliesFlies(stable, house,(stable, house,horse, deer)horse, deer)+ Annoyance+ AnnoyanceWoundsWoundsRepellents SummerRepellents Summer

Stable fly

Major insecticide classesMajor insecticide classes

Class Example NotesClass Example NotesBotanicals Pyrethrin family Ear tagsBotanicals Pyrethrin family Ear tagsPyrethroid family SafePyrethroid family SafeOrganophosphates Tiguvon® (fenthion) SpraysOrganophosphates Tiguvon® (fenthion) SpraysCarbamates Ear tagsCarbamates Ear tagsOral (some)Oral (some)Toxic!Toxic!Formamides Amitraz Lice/ticksFormamides Amitraz Lice/ticksFatal to horsesFatal to horsesDDT derivatives Methoxychlor HorsesDDT derivatives Methoxychlor HorsesDustDustSpraysSprays

Keys To Pesticide SafetyKeys To Pesticide Safety

Before using any pesticide, stop and read Before using any pesticide, stop and read the precautions.the precautions.

Read the label on each pesticide container Read the label on each pesticide container before each use. heed all warnings and before each use. heed all warnings and precautions.precautions.

Store all pesticides in their original Store all pesticides in their original containers away from food or feed.containers away from food or feed.

Keep pesticides out of the reach of Keep pesticides out of the reach of children, pets and livestock.children, pets and livestock.

Apply pesticides only as directed.Apply pesticides only as directed. Dispose of empty containers promptly and Dispose of empty containers promptly and

safelysafely

References References

http://edis.ifas.ufl.edu/IG139