Mahatma Jyotiba Fule College of Veterinary Science and Animal Husbandry, Chomu (Raj.)

Hard Ticks

Dr. Abhinav Meena

Assistant Professor

DEPARTMENT OF VETERINARY PARASITOLOGYCOLLEGE OF VETERINARY SCIENCE & ANIMAL HUSBANDRY,

CHOMU (RAJ.)

Ticks

• The ticks are obligate, blood-feeding ectoparasites of vertebrates,

particularly mammals and birds.

• Ticks are usually larger than mites, ranging in length from 3 to 12 mm, or more in the case of engorged females.

• Ticks are important vectors of zoonotic diseases (Lyme disease, Rocky Mountain spotted fever, etc.),

• Ticks do not possess antennae.

Families

• Two Families

The Ixodidae (Hard Ticks - scutum is present) and Argasidae (Soft

Ticks - scutum is absent)

• A third family of tick, the Nuttalliellidae, contains only a single,

little-known species which is found in the nests of swallows in

southern Africa.

Hard Ticks

Life Cycle

• The life cycles of ixodid ticks involve four instars:

• egg,

• six-legged larva,

• eight-legged nymph

• eight-legged adult

Each female may produce several thousand eggs.

• They wait at the tips of vegetation for an appropriate host to brush past.

• Once contact is made the ticks transfer to the host, and then move over the surface to find their preferred attachment sites, such as the ears.

• Eggs are always laid in the environment.

• Blood-feeding typically takes between 4 and 6 days.

• Ticks, particularly in the immature stages, are very susceptible to desiccation.

Types of life cycle

• One Host Tick (Larvae, nymphs and adults on same host ).

• Two Host Tick (Larvae & nymph on same host but adult on different host).

• Three Host Tick (Larvae, nymphs and adults all feed on differenthosts).

Clinical signs

• Presence of parasites

• Local skin infections

• Inflammed nodules are also seen

Diagnosis

• The adult ticks, particularly the engorged females, are easily seen on the skin.

• The predilection sites being the face, ears, axilla and inguinal region.

Family Ixodidae

• Important vectors of protozoal, bacterial, viral and rikkettsial diseases Ixodid ticks are responsible.

• Ixodid ticks are relatively large (2—20mm).

• The ixodids have a chitinous covering or scutum which extends over the whole dorsal surface of the male, but covers only a small area behind the head in the larva, nymph of female.

• Festoons (A row of notches ) is on posterior border of the body.

• Ixodidae the anal groove is either absent or is posterior to theanus.

• Some ticks have coloured enamel-like areas on the body and these arc called 'ornate ticks’.

• The adults have a pair of spiracles behind the fourth pair of legs.

• Eyes, when present, are situated on the outside margin of thescutum.

• If the scutum has a pattern of grey and white on a dark background, it is described as ornate, if not it is described as inornate.

• The anterior gnathosoma (or capitulum) and posterior idiosoma,which bears the legs.

Generas

• Ixodes

• Haemaphysalis

• Dermacentor

• Hyalomma

• Rhipicephalus

• Boophilus

• Amblyomma

Ixodes

Host

• Mammals and Birds

Species found in Eurupe:,

• Ixodes ricinus castor bean tick

• Ixodes canisuga British dog tick

• Ixodes hexagonus hedgehog tick.

Some other species:

• Ixodes holocyclus the paralysis tick ofAustralia

• Ixodes rubicundus the paralysis tick of SouthAfrica

• Ixorles scupularis (Black-legged Tick) the shoulder tick of NorthAmerica.

Identification

• Inornate ticks

• No eyes

• No festoons

• Palps are Long

• Anal groove is present anterior to the anus

I. ricinus

• In I. ricinus, as compared with I. canisuga and I. hexagonus, the tarsi are tapered and not humped

• The engorged adult female is light grey, up to 1.0 cm in length and bean shaped

• Adult male Ixodes Ricinus are only 2.0–3.0 mm long,

• the four pairs of legs

• Nymphs resemble the adults but are less than 2.0 mm in length.

• The larvae, often described as ‘seed ticks’ or ‘pepper ticks’, areless than 1.0 mm in length and usually yellowish in colour

Life cycle

• 3 host tick

• 3 years (life cycle)

• Mating takes place on the host.

• the female subsequently feeds for about 14 days and then dropsto the ground to lay several thousand eggs in the soil in shelteredspots, over a period of about 30 days, after which it dies.

• the larvae, nymphs and adults feed for a total of only 26-28 days.

• Unfed larvae can survive for approximately 13–19 months, unfed nymphs for 24 months and unfed adults for 21–31 months, but the precise period over which they can survive depends on temperature and humidity.

Importance

• heavy infestations can cause anaemia.

• Also at slaughter the value of the hide or fleece may be reduced.

• Europe, in cattle it transmits Babesia divergens and B. bovis, the causes of redwater fever and Anaplasma marginale, the cause of anaplasmosis in cattle

• In sheep and cattle, it transmits the virus that causes louping-ill and the rickettsia responsible for tick-borne fever.

• tick pyaemia, caused by Staphylococcus aureus

• transmit Borrelia burgdorferi, the spirochaete responsible for Lymedisease in humans

Ixodes Canisuga (Dog Tick)

• Infestation may cause dermatitis, pruritus, alopecia and anaemia,

• Adult females lay relatively small numbers of eggs, probably about 400 eggs.

• It may be a particular problem in packs of dogs in kennels.

• It may be differentiated from I. Ricinus by the presence of humped tarsi and the absence of a spur on the posterior internal angle of the first coxa.

Ixodes Hexagonus (Hedgehog tick)

• The scutum is broadly hexagonal

• It may be differentiated from I. ricinus by its humped tarsi and the fact that the spur on the first coxa does not overlap the second coxa.

• Adults are red–brown,

• Ixodes hexagonus is a biological vector of Borrelia spp and tick-borne encephalitis.

Haemophysalis

• Inornate ticks

• Festoons absent

• Eyes present

• 3 host ticks

• Sensory palps are short and broad

• Males have no ventral shield

• Short mouth parts

• Rectangular base capitula

• the second segment extending beyond the basis capituli.

• The anal groove is posterior to the anus.

Haemaphysalis punctata

• The transmission of Babesia major and Babesia bigemina, Theileria mutans (T. buffeli/orientalis), Anaplasma marginale and A. centrale in cattle.

• In sheep, it transmits Babesia motasi and the benign Theileriaovis.

• cause tick paralysis

Haemaphysalis leachi (Yellow dog tick)

This species is responsible for the transmission of

• canine piroplasmosis (B. canis) in dogs,

• tickbite fever (Rickettsia conorii)

• Coxiella burnetii

Haemaphysalis longicornis

• The main result of infestation is tick worry.

• This lowers production in cattle and tick bites damage hides.

DERMACENTOR

• medium-sized to large ticks,

• ornate patterning

• The palps and mouthparts are short

• the basis capituli is rectangular

• Festoons and eyes are present.

• Coxae progressively increase insize from I to IV. and, in the adult male , the coxa of the fourth pair of legs is greatly enlarged.

• The males lack ventral plates

• Three host tick and one host tick

Dermacentor variabilis

• American dog tick, wood tick

• Hosts: Dog, horse, cattle, man.

• three-host tick,

• 4000–6000 eggs

• Geographical distribution: NorthAmerica

• D. variabilis may cause tick paralysis in dogs

• In cattle it may transmit bovine anaplasmosis

• It is also an important vector of Rickettsia rickettsii (Rocky Mountain spotted fever) in the USA

• D.variabilis are responsible for the transmission of Anaplasma marginale incattle

Dermacentor nitens (Tropical horse tick)

• Hosts: Horse, cattle, man, many domestic and wild mammals. Horses are the preferred host of this species.

• 3500 eggs

• Dermacentor nitens is an important vector of Babesia caballi,resulting in equine babesiosis.(transovarially)

• Dermacentor nitens and D. albipictus are one-host ticks

AMBLYOMMA

• Eyes and festoons are present.

• Ornate ticks

• Ventral plates are absent in males

• Palps and hypostome are longer (Long mouthparts)

• Three host ticks

• Present in the head and neck region of domestic

animals

Amblyomma americanum (Lone star tick)

• because of a single white spot on the scutum of the female (lone star tick)

• This tick is most commonly found on the ears, flanks, head and belly

• Bites may cause tick paralysis

• Amblyomma americanum is an important vector of Rickettsia rickettsii (Rocky Mountain spotted fever) and Francisella tularensis (tularaemia).

Amblyomma hebraeum & A. variegatum (Bont ticks)

• ‘Bont ticks’ transmit the important disease, heartwater, in cattle, sheep and goats; it is caused by the rickettsia, Ehrlichia rumination

Amblyomma cajennense (Cayenne tick)

• most commonly equines

• This species transmits spotted fever in South America andLeptospira pomona.

• Painful biting

• Amblyomma gemma may be a vector for the transmission of heartwater in cattle, sheep and goats.

Amblyomma maculatum (Gulf coast tick)

• A. maculatum, is not known to transmit disease

• does cause severe bites and painful swellings

• The wounds created by this species may create a suitable site for screwworm myiasis associated with Cochliomyia spp.

BOOPHILUS (blue ticks)

• The palps and hypostome are short.

• The males have adanal or accessory ventral shields.

• The basis capituli is hexagonal dorsally.

• The mouthparts are short

• Inornate ticks

• Eyes present

• Festoons absent

• These ticks are most important vectors of Babesia spp andAnaplasma marginale in cattle

• Boophilus annulatus is an important vector of Texas cattle fever caused by Babesia bigemina and B. bovis.

• B.microplus present in every continent

HYALOMMA

• Eyes present

• long mouthparts.

• The males have ventral plates on each side of the anus.

• Hyalomma spp are usually two-host ticks,

• They are most commonly found on the legs, udder, tail or perianal region.

• Festoons sometimes present

• Inornate ticks

Hyalomma anatolicum (Bont-legged tick) & Hyalomma detritum & Hyalomma dromedarii (camel tick)

• mainly responsible for tick toxicosis,

• The ‘toxin’ produced by the adult tick causes a sweating sickness in ruminants

• pigs characterised by a widespread hyperaemia of the mucousmembranes

• a profuse moist eczema.

• Hyalomma aegyptium (tortoise tick)

• Hyalomma excavatum is a vector for the transmission of Theileriaannulata, causing tropical theileriosis

• vectors of several babesial, theilerial and rickettsial infections

RHIPICEPHALUS

• Inornate ticks

• Eyes and festoons are present

• Males have adanal plates and accessory shields

• Palps & hypostome are short

• Basis capituli are hexagonal dorsally

• 3 host tick (usually) and 2 host tick

• First coxa has two spurs

Rhipicephalus appendiculatus

• Common name: Brown ear tick

• three-host tick and mating takes place on the host.

• the most efficient vector of East Coast Fever of cattle caused by Theileria parva and also transmits Babesia bigcemina and the virus of Nairobi sheep disease.

Rhipicephalus sanguineus

• Common name: Brown dog tick, kennel tick

• 3 host tick

• Rhipicephalus sanguineus is primarily parasitic on dogs and is responsible for the transmission of Babesia canis and Ehrlichia canis and can also cause tick paralysis in the dog.

Rhipicephalus evertsi

• Common name: Red-legged tick

• black scutum,

• two-host species of tick

• can also transmit theilerial infections and Babesia bigemina and b. equi.

Control

• use of chemical acaricides applied either by total immersion in a dipping bath or in the form of a spray, shower, spot-on or slow-release ear tags.

• A wide variety of formulations of organophosphate and pyrethroid insecticides are available for application as sprays, dips, spot-on or showers

• Macrocyclic lactones or closantel given by the parenteral route have also been shown to be a useful aid in control of ticks.

• The avermectins & milbemycins may play an increasing role in thecontrol of one-host ticks.

• severely parasitised animals require individual treatment, special formulations of acaricides suspended in a greasy base may be applied to affected areas.

• topical acaricidal compounds, such as fipronil (phenylpyrazole), imidacloprid (chloronicotinyl), selamectin (macrocyclic lactone), amitraz (formamidine) and the organophosphates (e.g. malathion, ronnel, chlorpyrifos, fenthion, dichlorvos, cythoate, diazinon, propetamphos, phosmet) and carbamates can be used to kill ticks on the host.

• cattle tick Boophilus microplus. (vaccine)

• natural resistance to tick infestations (Genetics)

• Traditional control methods such as burning of cattle pastures

• Pyrethroids (e.g. permethrin, deltamethrin) should not be used in cats.

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