Arthropoda
introduction
By
Assist. Lecturer Maytham A. Alwan
4/13/2015
Arthropoda
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida (scorpions, spiders, mites, and ticks) (1)
Order: Acarina (ticks and mites)
Class: Insecta (insects) (2)
Order: Phthiraptera (lice)
Order: Siphonaptera (fleas)
Order: Diptera (two-winged flies)
Class: crustacea(copepoda) such as (crabs, crayfish, Cyclops) (3)
Class: Myriapodes (centipedes, Millipedes) (4)
Class: Onychophora (peripatus) (non parasitic)(5)
Phylum: Arthropoda
phylum
Class
Order
Arthropoda
Arachnida
Acarina
Ticks
Mites
Insecta
Diptera
Phthiraptera
Siphonaptera
flies
lice
fleas
Others
e.g. Hemiptera
bed bugs
Arthropods
The phylum Arthropoda contains over 80% of all known animal
species.
General characterizations of arthropoda
1. arthropoda have two parts arthos (mean joints), pods (mean
foot).
2. arthropoda are invertebrates organisms.
3. Its body covered by hard chitin which is termed exoskeleton.
4. Body divided to three parts(regions): the head, thorax and
abdomen.
5. There are one or two pairs of antenna connected to the head.
6. Members of this phylum have six appendages for insects and
eight for arachnida.
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arthropoda: morphology
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morphology
Morphology
Arachnids: body divided into two parts (cephalothorax [fusion of
head and thorax] and abdomen) or completely fused; adults with
four pairs of legs; antennae absent; wingless. Insects: body
divided into three parts (head, thorax, abdomen); adults with three
pairs of legs; antennae present; wings present or absent.
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arachnida
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Insecta
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arthropoda
Importance
1. Intermediate hosts for various parasites.
2. Vectors for bacteria, viruses, and other
pathogens.
3. Direct causal agents of disease. Produce
venoms that may be toxic.
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Ticks
Morphology
Arachnids: body divided into two parts (cephalothorax [fusion of head
and thorax] and abdomen) or completely fused; adults with four pairs
of legs; antennae absent; wingless.
• 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 or female. The mouthparts
carried on the capitulum are anterior and visible from the dorsal
surface, consist of pair of chelicerae and pair of pedipalps.
Ticks
Other distinguishing features are a series of
grooves on the scutum and body, and in some
species, a row of notches, called festoons, on the
posterior border of the body. The genital opening
is in the ventral mid-line and the anus is
posterior. Some ticks have coloured enamel-like
areas on the body and these are called `ornate
ticks'. Eyes, when present, are situated on the
outside margin of the scutum.
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Ticks
Scanning Electron Micrograph
of Tick Mouthparts
Ticks
Hard Tick (Family Ixodidae)
Soft Tick ( family Argasidae)
Female hard tick
Male hard tick
Tick life cycle
Life Cycle
Simple metamorphosis with larval and nymphal stages resembling adults.
Separate sexes with females laying eggs off the host. Larva (six legs, no
reproductive organs) hatches, feeds on host and molts to nymph.
Nymph (eight legs, no functional reproductive organs) feeds on host and
molts to another nymph (soft ticks) or adult (hard ticks).
Soft ticks have two or more nymphal stages; hard ticks have only one.
Then nymph molt to give adult tick. Soft ticks tend to live inside
(burrows, dens, hutches, etc.), feed rapidly, and spend relatively little
time on the host. Hard ticks tend to live outdoors, feed slowly, and
spend longer time on the host.
lifecycle
Most ticks cannot tolerate direct sunlight, dryness,
or excessive rainfall; tick activity decreases during
the cold months and increases during spring,
summer, and fall.
Hard ticks can be classified as either one-host (all
stages on one host, Boophilus annulatus), twohost (two stages on one host, Rhipicephalus
bursa), or three-host (all stages on different hosts,
Rhipicephalus appendiculate) ticks.
Character
Argasidae (Soft Ticks)
Scutum
•
Absent
Ixodidae (Hard Ticks)
•
Present(Males-covers
entire dorsal surface , females-covers part of
dorsal surface)
Mouthparts •
Hidden when viewed from the dorsal
surface
•
Visible when viewed from the dorsal
surface
•
Larvae feed slowly, over several
days; nymphs and adults feed quickly,
several times
•
Larvae, nymphs, and adults feed once,
requiring several days to repletion
•
Egg, larva, two or more nymphs,
adult
•
Egg, larva, nymph, adult
•
May be infect human& other animals
Feeding
Life stages
infestation
Species
•
•
May be infect only the birds
•
Argas americanus, A. persicus,
Ornithodoros moubata, Otobius
megneni
Ixodes, Rhipicephalus bursa, R.
appendiculate, R. sanguineus, Hyalomma
anatolicum, Hyaloma dromadarii,
Amblyomma maculatum, A. americanum,
Boophilus annulatus, Dermacenter
andersoni, D. venustus, D. variabilis
Ticks
Hard ticks
•
Genus Ixodes spp. causes Lyme Disease
•
Genus Hyalomma: H. marginatum (Crimean-Congo hemorrhagic fever)
•
H. anatolicum found in Iraq( H. anatolicum) transmit theileriosis(Theileria hirci)
Hard ticks
Genus : Rhipicephalus: African origin, but several species worldwide in the tropics
R. sanguineus (Brown Dog tick) cosmopolitan distribution (RMSF)
Found in Iraq(Rhipicephalus turanicus transmit Babesia bovis, B. bigemina) in
cattle.
Genus Boophilus annulatus non-ornamented,
one-host ticks (Cattle Fever tick) southern US,
Mexico (Texas Cattle fever) (found in Iraq
transmit Babesia bigemina, Anaplasma marginale
in cattle).
Hard ticks
• Genus Dermacentor: Ornate ticks
D. variabilis
D. andersoni
• Genus Amblyomma: Large ornate ticks
• A. americanum (Lone Star tick)
Soft tick
• Genus Argas: most nocturnal bird-associated
A. persicus (Fowl tick) cosmopolitan (economic importance, painful bite)
• Genus Ornithodoros: Reservoirs and vectors of relapsing fever
fever
Soft tick
• Genus Otobius:
• O. megnini (Spinose ear tick) (nymphal infestations in ears)
Ixodes
Boophilus
Argas persicus
Otobius megneni
Ornithodoros moubata
Rhipicephalus sanguineus
Hard ticks
Hyalomma anatolicum
Diagnosis
Ticks should be collected carefully in order to keep the
mouthparts intact. Preserving intact specimens in 70%
ethanol or isopropyl alcohol is recommended, although
5% formalin will do. The specific identification of ticks
can be challenging, particularly if dealing with larval or
nymphal forms. However, adults can be identified to
genus using the shape of their capitulum and length of
their mouthparts, the presence or absence of markings
on the scutum, and body structures.
Tick Removal:
1. Use fine-tipped tweezers or
shield your fingers with a tissue,
paper towel, or rubber gloves.
When possible, persons should
avoid removing ticks with bare
hands.
2. Grasp the tick as close to
the skin surface as possible
and pull upward with steady,
even pressure. Do not twist or
jerk the tick; this may cause
the mouthparts to break off
and remain in the skin.
Removal of an embedded tick using finetipped tweezers.
Treatment and Control
To control R. sanguineus indoors, spray building with
Diazinon. Remove vegetation and debris from bed and
yards to decrease tick survival. Spray or dust with
acaricide to kill those that remain. For lactating dairy
cattle, coumaphos and dichlorvos can be used. These
and malathion may be used in nonlactating beef and
dairy cattle. Coumaphos is effective for horses.
Insecticidal dusts or emulsion concentrates are used in
the treatment of O. megnini infestations.
Tick borne disease
A . Rickettsial infection : causative agent of
1. trench fever .
2. Rocky mountain spotted fever caused by Rickettsia
rickettsia transmitted by ixodid tick.
3. Query fever transmitted by tick of small mammals.
B . Tick borne bacterial infections: ixodid and argasid ticks
serve as vectors of several pathogenic bacteria
1.Relapsing fever (recurrent fever) caused by Borrelia duttoni.
2.Tularemia : it is an infectious bacterial disease caused by
Francisella tularensis.
C. Tick borne viral infections :
Encephalitis and haemorrhagic fever
D. Tick borne parasitic(protozoa) infections:
1. Babesiosis (Texas cattle fever)
2. Theileriosis (east coast fever)
3. Anaplasmosis
E. Generally ticks causes : 1. Local inflammatory and
traumatic damage at the site of attachment.
2. Systemic damage may result in tick paralysis due to toxic
substance secreted by salivary glands of ticks.
spotted rash of late-stage Rocky Mountain
spotted fever
erythema chronicum migrans
(bull’s eye rash) Lyme disease