TICKS

• Phylum Arthropoda represents largest number of known

animals (at least 760,000 species)

• Phylum Arthropoda divided into 5 classes, class Arachnida

includes most of the parasites have medical and economic

importance ( such as ticks and mites)

• The interest of parasitologists in ticks and mites stems from

three avenues of investigation—

1. That concerned with the parasitic habits of acarinas,

2. That concerned with their role in the transmission of

pathogens (that is their role as vectors),

3. That concerned with their role as intermediate hosts of

certain helminths

INTRODUCTION

ZOOLOGICAL CLASSIFICATION

Phylum: Arthropoda (Jointed appendages)

Class: Arachnida (2 regions of the body i.e.

cephalothorax and abdomen)

Order: Acarina (Segmented pores)

Suborder: Ixodoidae (Metastigmata)

Family:

Ixodidae (Hard ticks)

(Dorsal shield present

Capitulum anterior)

Genus:

Ixodes spp

Boophilus spp

Rhipicephalus spp

Argasidae (soft ticks)

(Dorsal shield absent

Capitulum ventral)

Genus:

Argus spp

Otobius spp

CHARACTERS AND MORPHOLOGY

Ticks are characterised by leathery

integument

Body of ticks divided into 2 regions:1. Gnathosoma

or

Capitulum

2. Body proper

Mouth parts bears three types of structures:

2- Hypostome

1- A pair of chelicerae

3- A pair of pedipalps

Scutum (Shield) present in Ixodid ticks,

covers entire dorsal surface of male

(antereomedial surface of females)

Certain male ticks bear undulation

(festoons)

Legs Larvae – 3 pair of legs

Nymphs and adults – 4 pair of legs

Semi-transparent suckers like carucle

(pulvillus) present on each tarsus

Genital pore located at the angle formed

by two genital grooves

CHARACTERS AND

MORPHOLOGY

Soft Tick

(Argas/ Ornithodoros )

Hard tick

(Dermacenter/Amblyomma )

Family Argasidae Ixodidae

Integument Leathery in nymphal and adult

stages

Same

Scutum no shield (or scutum) Covers entire surface of the body

in males and only an anteromedial

portion in females

Capatulum Either sub-terminal or protruding

from outer margins of body in

nymph and adult while terminal in

larvae

Anterior and visible from the

dorsal side of scutum

Pedipalps flexible and not intimately

associated with hypostome

rigid and are intimately in

associated with hypostome

Eyes Usually absent if Present located

Supra- coxal folds

If present located dorsally on

sides of Scutum

Sexual

Dimorphism

Slite Marked

CHARACTERS AND MORPHOLOGY

GENERAL LIFE CYCLE OF TICKS

LIFE CYCLE OF HARD TICKS

FAMILY IXODIDAE

6400 eggs

LIFE CYCLE OF SOFT TICKS

FAMILY- ARGASIDAE

Last nuymphal moulting to

adult-11 days

For each nymph instar-

Emerges to feeding-3 days

Nymphal moulting-11 days

No. of nymphal instar-4-7

Embryogenesis on the

ground (8-13 days)

Larval moulting- 5 days

No larval blood meal

nymph

adult

eggs

larvae

Number of adult blood

meal 1-10

Several laying after a

single copulation

No. of eggs 350

PARASITIC

ADAPTATION

S

Morphological

adaptation

Physiological

adaptation

Adaptation to

starvation

time

Life cycle

adaptationBehavioural

adaptation

Reproductive

adaptation

PARASITIC ADAPTATIONS

Morphological adaptationsthe scutum- adapted for protection but it is

also limiting,

Pedipalp- act as counter anchor at the time of

attachment of tick to host

Hypostome (organ of attachment) recurved

teethes present on it, helps in host’s skin

attachment

The chelicerae are the cutting organs used to

penetrate the host’s skin and gain access to its

blood, compromise three parts, the cheliceral

base, an elongated shaft, and the cutting

digits.

Haller’s organ (On the dorsal surface of leg)

is specialized in determining host location,

host odours, and also detecting pheromones

as well as other sensory functions.

PHYSIOLOGICAL ADAPTATION

• Sensilla provide information on the biochemical characteristics of the

wound site environment.

• They can use this sensory adaption to detect minute differences in skin

tissue temperatures.

• These types of sensory information facilitate blood sucking behaviour.

BEHAVIOURAL ADAPTATION

• Small body helps to attachment on host and hiding

from predators.

• They use blades of grass to elevate themselves to the

height, where they can easily grasp the host.

REPRODUCTIVE ADAPTATIONS

• They produce large number of eggs in comparison

to mites.

• They produce eggs in several batches(soft tick) and

large number of eggs(hard tick), for increasing their

survival.

ADAPTATION TO STARVATION TIME

• Their starvation period is so long because hosts are not

easily available.

• Larvae live more than 6 months without food.

• Adult have been kept alive in corked vials for 5 years.

LIFE CYCLE ADAPTATION

• Their life cycle adapted for 1-3 host (hard ticks) and

multiple host(soft ticks), taking blood meal several

times to increase their size(soft ticks, nymph).

• In adult taking blood meal to produce viable eggs.

TICK BORN DISEASES

Disease Etiological agent Tick vector Endemic Area

Babesiosis Babesia bigemina Boophilus

annulatus

USA Australia

Rocky

mountain

spotted fever

Rickettsia rickettsi Dermacentor

variabilis

United state,

Canada

Queen’s land

tick typhus

Rickettsia australis Ixodes holocyclus Australia

Q fever Coxiella burnettii Dermacentor

venustus

World wide

Lyme disease Borellia burgdorferi Black legged tick USA, Europe

Avian

spirochetosis

Borellia anserina Argas persicus India, Australia

LYME DISEASE

Known as “great imitator” because symptoms

of disease can mimic many other illnesses.

Caused by- Borrelia

Transmitted by- deer black legged tick

Symptoms-

Erythema migrans (expending red rash), fever,

swelling of lymph nodes, pain

Lameness arthritis is the important symptom

of disease

BABESIOSIS/ PIROPLASMOSIS

• It is malaria like disease

• Parasite affect red blood cells

• Causative agent- genus Babesia (B.

microti)

• Transmitted by- Ixodes, Boophilus

• Initial symptoms may occur after 1-8

weeks of bite

• Apart from tick bite, blood transfer may

also a risk factor

PATHOLOGIC ALTERATIONS

1. LOCAL DAMAGE-

• Local inflammation at the site of attachment,

itching, haemorrhage

• Invasion of auditory canal by spinous ear

ticks

2. SYSTEMIC DAMAGE-

• Anticoagulant releasing at the time of feeding

causes a type of sensitization reaction

• Bite may also causes paralysis (common in

sheep and calves)

TREATMENT

• Antibiotic therapy

• Doxycycline and amoxicillin are used for

2-4 weeks in early cases.

• Cefuroxime axetil or erythromycin for

allergic patients

• Treatment with intravenous ceftriaxone or

penicillin for 4 weeks

PREVENTION AND

CONTROL

Personal protection

Tucking trousers into boots and shirts into pants, using

repellent for exposed skin and an approved toxicant for

clothing, and performing regular clothing and body checks

should be routine in tick habitat.

• Habitat alteration can be very effective.

• Exclusion of host animals (e.g., deer) can

cause major reductions in populations of ticks

that feed on deer.

• Keep vegetation short, widen paths and advise

users to stay on the paths in order to avoid ticks.

Removal of ticks• Use fine tipped tweezers to

grasp the tick

• Pull upward with steady even

pressure. Don’t twist or jerk

the tick

• After removing, thoroughly

clean the bite area and hands

• Never crush ticks with finger

Use of pesticides

BHC

Organophosphorus

Chlorinated hydrocarbons

DDT

Turpentine oil

Integrated Vector Management (IVM)

• Minimize exposure to ticks

• Sanitation and exclusion

• Chemical control

• Biological control

THANK YOU….