Ticks and mites are external parasites that feed on blood and transmit diseases. Hard ticks remain attached while feeding, have a dorsal shield, and take several days to feed. Soft ticks leave after brief feedings. Scabies mites burrow under the skin and cause itching. Lice live on humans and transmit diseases. Cyclops are small crustaceans that act as intermediate hosts for diseases like Guinea worm. Controlling these parasites involves preventing contact, delousing with chemicals, boiling or filtering water, and engineering controls.

1. Dr. Sookun Rajeev K
M.D
Dept. Of Community Medicine

2. TICKS

3. The Ticks
•Are small Arachnids.
•They have no antennae.
•3 pairs of legs in larval stage and 4 pairs of legs in adult
stage.
•They are external parasites living suck blood of mammals,
birds and sometimes reptiles and amphibians.
•The 2 families of medical importance are Ixodidae (Hard
Ticks) and Argasidae (Soft Ticks).
•The Hard Ticks remain attached to the host while Soft Ticks
leave the host after feeding.

4. Identifications
Features Hard Ticks (Ixodidae) Soft Ticks (Argasidae)
Scutum (Dorsal Shield)
Capitulum (Mouth Parts)
Nymphal Stages
Adult Feeding time
Female blood meals
Egg laying events
Total egg laid
Present
Anterior, Visible from
above
One
Several days
One
One
3000 - 8000
Not Present
Ventral, Not visible from
above
Several
30 – 60 mins
Several
Several
400 - 500

5. Hard Tick
Male
Female

6. Soft Tick
• Abdominal wall is
smooth
• Dorsal surface has small
dot like mamillary
tubrercles
•Small, soft and leathery cuticula,
•Mouthparts invisible from dorsal
aspect
•The scutum/dorsal schield is
`absent

7. Hard Tick and Soft Tick

8. Diseases Transmitted
• Lyme disease
• Q Fever
• Colorado Tick Fever
• Rocky Mountain Spotted Fever
• African Bite Fever
• Crimean Congo Hemorrhagic Fever
• Tularemia
• Tick-Borne Relapsing Fever
• Babesiosis
• Tick-Borne Meningoencephalitis

9. Control Measures
• Dimethyl phthalate (DMP) is a good tick repellant,
especially against larvae.
• Clothes dipped in 5 percent DMP and 2 percent soap
solution retain the repellant effect for one to two months.
• Infested animals may be dusted with lindane, malathion or
DDT.

10. Itch Mite (Sarcoptes Scabiei)

11. Identifications
• Tiny (0.1-0.3 mm) endo-parasitic mite
• Lives in epidermal layer of skin
• Body - Capitulum & Abdomen
• Eyes, antennae & wings are absent
• 2 pairs of legs in front 2 pairs
behind.Front legs end in long tubular
process-suckers
• Hind legs end in long filamentous bristles
• In females 4th pair end in suckers

12. The Itch Mite
• Causes human scabies
• Scabies is characterized by an intensely pruritic,
erythematous, papular eruption caused by burrowing
of adult female mites in upper layers of the epidermis,
creating serpiginous burrows. Itching is most intense
at night
• Sites of lesion – hands & wrist (63%),extensor aspect
of wrist (11%),

13. Preferred sites interdegital, popliteal fold and groin

14. Diseases Transmitted
• Scabies

15. The Itch Mite

16. Control Measures
• Avoid direct contact with the infested person.
• Proper personal hygiene should be observed including bath with soap and water.
• The infested persons and contacts should be treated thoroughly with 3 – 5 % sulfur
ointment or 20 - 25 % benzyl benzoate emulsion. The patient should take hot bath
with soap and water, scrub the affected parts with brush, dry the body with rough
towel, and rub the medicine all over, especially over the affected parts. He should
then put on clean clothes and take no bath for 48 hours. The old clothes should be
sterilised by boiling. Second application may be necessary.
• 5% tetmosol solution is a good sarcopticide and can be applied tds.
• 0.5 to 1 % BHC or Gamma HCH (lindane) in coconut oil is a good sarcopticide when
applied on the affected part bd or tds at interval of two to three days.

17. LICE

18. The Lice
• These are blood sucking insects with a dorsoventrally flattened body and clawed
legs.
• Both sexes live on the host itself.
• Gray in color and 2 to 3 mm long.
• They can live for a week without feeding.
• Head and body lice look alike and interbreed.
• The head is conical, joined with the thorax by a constriction.
• It bears a blood sucking proboscis and two antennae.
• The head louse is darker, smaller and brisker than the body louse.
• The crab louse is 1 to 2 mm long and has a squarish shape.
• It has a blunt, truncated head and strong legs, hence the name. It is found in pubic
and perineal hair.
• Louse bites cause irritation and sometimes, urticaria. Prolonged infestation may
result in deep pigmented skin or melanoderma.

19. Identifications
• The following three species infest man:
• 1. Pediculus capitis (Head louse)
2. Pediculus corporis (Body louse)
3. Phthirus pubis (Crab or pubic louse).
• Habitats correspond to their names.
• Lice infestation of any part of the body is known as PEDICULOSIS
• Body of louse is divided into 3 parts:
1. Head: bears a pair of antennae,each with 5 segments.
2. Thorax : 3 pairs of legs attached ventrally.
3. Abdomen: elongated and consists of 9 segments

20. Louse

21. Diseases Transmitted
• P. corporis and P. capitis transmit Rickettsia prowazeki, the
causative agent of epidemic typhus, and quintana, the
causative agent of trench fever.
• The crab louse is not known to transmit any disease.
• The head and body lice also transmit Borrelia recurrentis
which causes relapsing fever. The organisms enter the body
when infected louse is crushed on the skin.
• Dermatitis may occur due to scratching and secondary
infection.

22. Control Measures
1)Prevention of Infection:
• Avoid contact with infested person. Hat, cap, comb, hair brush
and clothes of an infested person should not be used.
• The bedlinen and under garments should be properly washed
and the hair combed as a part of personal hygiene. If necessary,
clothing may be dusted with carbaryl powder in highly lousy
surroundings.

23. ) Delousing Measures:
• Applying 2 percent DDT emulsion or dusting with 10 percent DDT.
• 0.2 percent lindane in coconut oil should preferably be used.
• 0.5 percent malathion lotion (1% in case of body louse) is effective. The lotion should be
allowed to act for 12 to 24 hours before the hair is washed.
• Carbaryl dust may also be used as louse powder.
• An emulsion designated NBIN (68 percent benzyl benzoate, 6 percent DDT, 12 percent
benzocaine and 14 percent Tween-80) applied after 1:5 dilution in water is also
effective against lice as well as nits.
• Leather, wool and silk may be deloused by soaking them in 2 percent cresol and 50
percent soap emulsion for one hour.

24. CYCLOPS

25. The Cyclops• Class-crustacea
• Up to 1-2 mm in size.
• Also known as water flea.
• They live in fresh water.
• The head and thorax are fused to form a bulbous cephalothorax.
• Abdominal portion is narrowed.
• They have 2 pairs of antennae and Single small pigmented eye.
• In females 1st abd. segment has a pair of ovisac

26. Identifications
Male
• Abdomen consists of lower
segment and ends as caudal fork
Female
• External ovisac with eggs is
present attached to abdominal
segment.

28. Diseases Transmitted
•Intermediate host of Guinea worm or Dracunculiasis
•Disease is transmitted when human drink contaminated
water infected with cyclops.
•Intermediate host of Fish tapeworm or Diphyllobothrium.

29. Control Measures• Cyclops can be controlled by Physical, Chemical, Biological and Engineering methods
1) Physical:
• Straining of water through a piece of fine cloth is sufficient to remove cyclops.
• Boiling water at 60o C kills cyclops.
2) Chemical:
• Chlorine destroys guineaworm larvae and cyclops.
3) Biological:
• Small fishes like Barbel and Gambusia feed on cyclops.
4) Engineering:
• Provision of drinking water through piping water supply, use of tubewells.
• Abolition of stepwells.