Arthropods are a phylum that includes insects, arachnids, crustaceans and others. They have an exoskeleton, jointed appendages and a tube-like heart. Some arthropods are medically important as vectors of diseases. The document discusses the characteristics and classification of arthropods, focusing on orders and species that can transmit pathogens like ticks that carry Lyme disease, fleas that transmit plague, and mosquitoes that transmit malaria. Prevention methods against arthropod bites are also outlined.

1. PHYLUM
ARTHROPODA(ARTHROPOD
CHARACTERISTICS)
Done by : Lamya Alsadhan
Supervised by : Ebtesam Alolayan

2. What Is an Arthropod?
• Arthropod, any member of the phylum
Arthropoda.
• includes such familiar forms as lobsters, crabs,
spiders, mites, insects, centipedes, and
millipedes.
• Arthropods are represented in every habitat on
Earth and show a great variety of adaptations.
• Some are aquatic, others are terrestrial, some
are free living, and others are parasitic.

3. Objective:
• To identify the common characteristics of medical arthropods
and its classification.
• To discuss the mechanisms of transmission and causation of
diseases.
• To describe the diseases caused or transmitted by medical
arthropods.
• To implement appropriate prevention, control, and
treatment.

4. General features:
• All arthropods have a body supported by a
hardened external skeleton (exoskeleton).
• The appendages of arthropods - their legs,
antennae, and mouthparts - are jointed.
• Internally, the nerve cord runs along the lower
(ventral) part of the body and is not enclosed in a
protective spinal column.
• Blood is moved by the aid of a tube-like heart.
• The overall body arrangement is bilaterally
symmetrical.

5. Distribution and abundance:
• Arthropods are found in
almost all of the habitats
that cover the Earth’s
surface, even in your own
room!

6. Importance:
• The larger crustaceans- shrimps, lobsters, and
crabs- are used as food throughout the world.
• Although many species of insects and mites
attack food crops and timber, arthropods are
of enormous benefit to human agriculture.
• The stings and bites of arthropods may be
irritating or painful, but very few inject
dangerous toxins.
• Medically, arthropods are more significant as
carriers of diseases.

7. Arthropods relations to us :
• Medical Arthropod:
• Arthropods related with human health.
• Medical Arthropodology:
• Morphology, taxonomy, life cycle, ecology,
transmission of the diseases, control measures.
• Examples:
• Flea  Bubonic Plague.
• Soft tick  Q fever.
• Mosquito  Malaria.

8. Harm for human health:
•Harmful cause nuisance.
•Ectoparasites.
•Mechanical
transporters.
•Vectors.

10. Subphylum Crustacea:
• Most crustaceans have: two pairs of antennae,
three pairs of chewing appendages, various
numbers of pairs of legs.
• Crustaceans differ from the insects in that they
have legs on their abdomen as well as on their
thorax.
• Medical importance: Cyclopes are intermediate
hosts of the fish tapeworm (Diphyllobothrium
latum) and Dracunculus medinensis.

11. Subphylum Chelicerata
Class Arachnida:
• The Class Arachnida includes spiders, scorpions, ticks,
and mites.
• Most arachnids are adapted to kill prey with poison
glands, stingers, or fangs.
• Arachnids have a body that is divided into a
cephalothorax and an abdomen.
• Incomplete metamorphosis.
• Class Arachnida includes 3 orders of medical
importance:
• Order Scorpiones.
• Order Araneae (spiders).
• Order Acari (ticks and mites).

12. Tick:
• Ticks are divided into hard-bodied
ticks (family Ixodidae) and soft-
bodied ticks (family Argasidae)
• Ticks are blood-feeding
ectoparasites
• Ticks are widely distributed around
the world, especially in warm, humid
climates.

13. Life cycle:

14. Hard and Soft ticks:
• Hard ticks:
• Suck in day.
• Feed on the host for a few days.
• Resting sites: forest, woods, grassland, pasturage.
• Soft ticks:
• Suck at night.
• Feed on the host from minutes to one hour.
• Resting sites: locate at the host’s nests and hovel.

15. Harm to humans:
• Direct injures
• Irritation
• Tick paralysis
• Transmission of diseases
• Tick-borne encephalitis.
• Tick-borne relapsing fever, Lyme
disease.
• Q fever and tick-borne typhus.

16. Mite:
• Mites are small arthropods belonging to the class
Arachnida and the order Acari (also known as Acarina).
• Most mites are tiny, and have a simple, unsegmented
body plan.
• some species live in water, many live in soil as
decomposers, while others again are predators or
parasites.
• Most species are harmless to humans but a few are
associated with allergies or may transmit diseases.

17. Itch mite (Sarcoptes scabiei ):
• Sarcoptes scabiei parasitizes on humans, which can
cause scabies.
• Most have piercing/sucking mouthparts, some have
chewing mouthparts. All are different from insects
• Most are 8-legged except for the 1st instar which is 6-
legged.
• All are extremely tiny. A big one is the size of a period
in your textbook. Some adults live inside hair follicles.
Some live inside trachea of insects.

18. Life cycle:
 Egg  larva  protonymph 
tritonymph  adult
 Larva - 3 pairs of legs
 Nymphs - 4 pairs of legs.
 The female burrows into the skin
and lays eggs in a sinuous tunnel.

19. Pathogenesis:
• Selects places where the skin is thin and
wrinkled. Between fingers, wrists, elbows, feet,
etc.
• Children may be found burrowing on whole body.
• The mite can cause more severe skin reactions,
such as itching and allergic reactions.
• The hypersensitivity may result from the mite
excretions.
• Secondary bacterial infections may also occur,
probably as a result of scratching.

20. Immune response in scabies:
• S. scabiei infestation results in inflammatory and adaptive immune responses
relatively late in the infection (4–6 weeks after initial contact with mite).
• It is believed scabies mites have developed the capability of modulating
various aspects of the host immune responses resulting in the delayed onset
of symptoms.
• The rash and itch associated with scabies shows features of both type I
(immediate) and type IV (delayed) hypersensitivity reactions.
• The initial inflammatory response towards the mite and its products consists
of Langerhans cells (LCs) and eosinophils with smaller number of monocytes,
macrophages and mast cells.

21. Diagnosis, Prevention and control:
• Symptoms: sinuous tracks in the
skin, inflammation, itching.
• Find the mites in the skin.
• All clothing and bedding should
be laundered in hot water, and
sun dried.
• 5% Permethrin ointment.

22. Class Insecta:
• Insects are relatively small, ranging in size from
0.1mm.
• Most insects have compound eyes, and many have
ocelli as well.The mouth parts of insects are
elaborate.
• One pair of antennae and one or two pairs of wings,
three pairs of legs, all attached to the thorax.
• Body is divided into head, thorax, and abdomen
• Larvae in insects are worm-like, which differ greatly
in appearance from the adults.

23. Insects as vector of diseases:
• As vectors of the agents of bacterial, viral or
parasitic infection.
• As parasites in their own right, spending part or
all of their lifespan on humans
• As instigators of allergic responses that vary in
severity.
• They are 2 types of vectors:
• Biological vectors
• Mechanical vectors

24. Class Insecta is divided into 4 orders of
medical importance:
•Order Anoplura (lice).
•Order Siphonaptera (fleas).
•Order Hemiptera (bugs).
•Order Diptera (mosquitoes and
flies).

25. Order Anoplura (lice):
• Body is flattened dorso-ventrally.
• Lice are wingless insects with short legs.
• Displays incomplete metamorphosis.
• Head louse (Pediculus humanus):
• Adult louse is 2-5 mm in size, male is smaller than
female.
• Body is divided into head, thorax and abdomen.
• Currently, head and pubic lice are not considered
to be vectors for human pathogens

26. Order Siphonaptera (Fleas):
• About 2500 species, most parasites of
mammal’s only approx. 100 species of birds.
• Temporary obligate parasites, blood-feeding
exclusively as adults.
• Most fleas of medical and veterinary importance
are not host specific, that increases the
potential for acquisition and transmission of
pathogens.
• Xenopsylla cheopis (Oriental rat flea) is primary
urban plague vector.

27. Order Hemiptera (Bed Bugs):
• Bed bugs get their name from their proclivity.
• They feed on blood, climbing on you as you sleep and
feasting.Their bites can cause severe redness and
itching.
• Some of them are not a big deal. But they're fast
breeders and hard to kill.They can hide in your carpet,
your clothes or even inside your walls.
• Bed bug bite causes anemia and lack of energy and in
extreme cases, death.

28. Order Diptera (mosquitoes and flies):
• Mosquitoes :
• Mosquitoes are one of the main disease carriers among insects.
• When they bite, they regurgitate a small amount of their stomach contents into
the new host.
• If a mosquito previously bit an infected person or animal, he can transfer that
disease to the new host. Ex: Malaria, typhoid and cholera.
• Flies:
• Flies often eat food we consider undesirable, such as rotting vegetation and
feces.
• Their bodies are covered with diseased particles, including their mouth parts,
feet and legs.
• Deposition of those diseased particles on food we eat, leads to food poisoning.
• Flies also transmit diseases such as typhoid and cholera.

29. Protection against Mosquitoes,Ticks, & Other
Arthropods:
• GENERAL PROTECTIVE MEASURES:
• Avoid outbreaks.
• Be aware of peak exposure times and places.
• Wear appropriate clothing..
• Check for ticks
• Bed nets.
• Insecticides and spatial repellents.
• Protective measures against bed bugs