ACARINA ( ACARI) ARTHROPODA CONSIST OF 6 CLASSES:

ARACHNIDA(5 ORDERS):

Scorpionida

Acarina

Aranea MOUTHPARTS:

ignathosoma

Digestion system HETEROMATABOLUS ARTHROPODES Differentiation of ticks and mites

 Ticks are much larger  Ticks have toothed hypostome

Metasigmata: family : I- Argasidae ( soft ticks)

 1- Argas spp  2- Ornithodoros spp

 Flattened dorsoventrally, oval  No scutum  Capitulum not visible dorsally

The coxal organs open between the bases of the first and second pairs of legs

Only in soft ticks

LIFE CYCLE OF ARGASIDAE:

•25 years recorded in lab.

•Mating occurs away from the hosts

Medical importance:

 I- Biting

 II- Tick-Born Relapsing fever

 III- Q fever TICK BORN RELAPSING FEVER: (TBRF)

• The only important disease

• Seven species of Borrelia each having different geographical distribution

• B. duttoni, spread by Ornithodoros moubata

• Agent: Borrelia duttoni in some texts: B. persica ( middle east and Russia ) B. turicata ( America and Mexico) B. hermsii ( North America)

• vector : Ornithodoros spp Ornithodoros tholozani O. moubata O. erraticus

Disease Cycle:

 Spirochetes ingested with a blood meal multiply in the gut  Pass across into the haemocoel ( after 24 hours)  Multiply enormously and invade all tissues and organs  Within 3 days arrive salivary glands, coxal organs and ovaries.

So: Ticks are main reservoirs, then rodents Symptoms:

 Relapsing episode of fever  Generalized body Diagnosis: aches, chills and sweats

 7 days after being  Observation of Borrelia bitten symptoms in smears of peripheral developed bloods and bone morrow

 Clinical symptoms Treatment:

•Antibiotics like tetracycline , vitamin k

•Current recommendation 7 days

•Borrelia persica •Ornithodoros tholozani In Iran:

•1382, 471 cases was reported •Mountainous area of western, northern and northwestern parts of Iran

CONTROL:

• Removing ticks from their hosts

•Repellent

•Impregnated clothing

•House spraying

•Plastering

•Rodent-proof buildings

•fumigation

Metastigmata: family : II- Ixodidae ( Hard ticks)  1- Ixodes spp  2- Dermacentor spp  3- Amblyoma spp  4-Haemaphysalis spp  5-Hyalomma spp  6-Rhipicephalus spp  Flattened dorsoventrally, oval  Capitulum projects forward  Scutum ( sexing)  No coxal gland

Life cycle

 Important different with soft ticks  Adult attach to their hosts for long periods (1-4 weeks)  Drops and seeks shelter  Thousands (1000-8000) eggs in a gelatinous mass  Oviposition may last 10 days  She dies

Life cycle of hard ticks:  six-legged hatch from the eggs, seed ticks  Inactive for a few days, climb up  Questing  Drop to the ground  Remain inactive then molt  Eight-legged nymphs  Questing  Drop and seek shelter  Moult to male or female adult  Mating on the host

Only one nymphal stage MEDICAL IMPORTANCE I- Tick paralysis

 Dermacentor, Ixodes, Amblyomma

 world wide

 Ascending paralysis ( 5-7 days after biting)

Usually a full recovery after tick removal

II- ARBOVIRUSES:

• 100 Arboviruses recovered from ticks

•All transmit by ticks bite

•Some Transovarial and transstadial transmission

 Tick- Borne Encephalitis  Russian Spring-Summer Encephalitis  Tick- Borne Encephalitis  Omsk hemorrhagic fever  Colorado tick fever  Kyasanur-forest disease  West Nile virus

 Transovarial Transsmission  Reseroir: rodents and ticks

II-7-Crimean-Congo hemorrhagic Fever

CCHF

III- Rhickettsia spp

III-1- Rocky mountain spotted fever III-2- Siberian Tick Typhus III-3- Boutonnos fever

 Agent:Coxiella burneti III-4-Q- fever:  World wide distribution

 Mainly in rodents and other small mammals

 Transmission ways:

- biting of argasidae and mainly Ixodidae - consuming contominated milk and other foods - transovarial and transstadial t. - mechanical transmission by house fly

IV-Lyme disease

* Agent: Borrelia burgdoferi complex

* Ixodes spp * zoonosis, reservoirs: cows, horses, dogs, ticks

* We have Ixodes ricinus in Iran. TULAREMIA

transmission

Transovarial

tularensis

consuming raw meat consuming , biting ticks hard contact with infected animal, carcasses animal, infected with contact water contaminated drink

Transmission ways: Transmission Reservoirs are rabbits, rodents are rabbits, Reservoirs Wide variety of wild variety of wild Wide mammals and birds North America, Europe, Japan, Asia Japan, Europe, America, North Francisella

4. 3.

2. 1.

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