and its parasitic adaptations for M.Sc. students

1. TICKS

2. • 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

3. 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

4. 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

5. 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

6. 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

7. GENERAL LIFE CYCLE OF TICKS

8. LIFE CYCLE OF HARD TICKS
FAMILY IXODIDAE
6400 eggs

9. 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

10. PARASITIC
ADAPTATION
S
Morphological
adaptation
Physiological
adaptation
Adaptation to
starvation
time
Life cycle
adaptation
Behavioural
adaptation
Reproductive
adaptation

11. PARASITIC ADAPTATIONS
Morphological adaptations
the 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.

12. 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.

13. 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.

14. 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.

15. TICK BORN DISEASES
Disease Etiological agent Tick vector Endemic Area
Babesiosis Babesia bigemina Boophilus
annulatus
USAAustralia
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

16. 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

17. 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

18. 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)

19. 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

20. 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.

21. 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

22. 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

23. THANK YOU….