10-B__Medical_arthropodology_ppt.ppt

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					Medical arthropodology
          General characters
            of arthropoda
   Bilateral symmetry, segmented body and
    appendages.
   Body consist of head, thorax and
    abdomen.
   Chitinous exoskeleton.
   Circulatory system is open.
   Growth is accompanied by periodic molting
    (shedding) Ecdysis and metamorphosis        .
       Harm for human health

    Direct harms


1. Harassment and sucking blood: mosquito, fly

2. Allergy and toxicosis: dust mite-asthma

3. Invading tissue: itch mite -scabies
                    maggot-myiasis
   Indirect harms
   (transmit pathogen,cause arbo-diseases)

1. Mechanical transmission
                                 Arthropods which
 Arthropods carry pathogens    from one person   to
                                transmit pathogens
                Medical
 the next withoutvector
                  development or multiplication of
               arthropod
 pathogens.                      Diseases transmitted
                                    by medical arthropods
2.Biological transmission
    pathogen                  sick
                          Arbo-disease
Pathogens develop or multiply within arthropods,
  only transmitted to vertebrate hosts.
         Types of biological transmission

    Development: pathogens develop to infective
stage in arthropod, no proliferation.

    larva of filaria       mosquito infective stage.

    Proliferation: pathogens proliferate in arthropod,
forms no change.

yersinia pestis                   flea bacteria embolism
    Types of biological transmission

 Development and proliferation: pathogens
develop and proliferate in arthropod.

Plasmodium: gametocyte                mosquito
great number of sporozoite.
                        Classification
       Five classes of Arthropod are medical important.
1.   Insecta venomous, vectors,
     intermediate hosts, parasites.

2. Arachnida venomous, vectors,                          crab&shrimp
     intermediate hosts.

3. Chilopoda they are poisonous
4. Diplopoda they are poisonous
5. Crustacea few species serve as         centipede
                                           tick
     intermediate hosts such as crabs &      millipede
     crayfishes
       Arachnida

Scorpiones   Araneae   Acari
         Araneae
BROWN RECLUSE SPIDER BITES

           • Found in midwest & south-
             central US
           • “Reclusive” nature
           • Found inside shoes,
             clothing, attics, cardboard
             boxes, etc.
BROWN RECLUSE SPIDER BITES


             • Painless bite
             • Followed by
               erythema, swelling,
               tenderness
             • Rare systemic
               reactions
BLACK WIDOW SPIDER BITES

            • Found throughout US
              & worldwide
            • “Red hourglass”
            • Neurotoxic venom
            • Pain but NO necrosis
            • Abdominal rigidity
                      Acari


tick: hard ticks,soft ticks
mite:Trombiculid mite,Itch mite
          Demodicidae mite,Dust mite
Morphological features
 1. Body regions consist of cephalothoraxand
abdomen or further fused to idiosoma.

2. No antennae, simple eyes.

3. No wings, 4(A) pairs of legs.
  Tick: hard ticks, soft ticks
 An inflexible, dorsal scutum covers the idiosoma of the male and
the body is are of smooth.
Theanterior usually the idiosoma of the female
Mouthparts partterminal and visible from above




               hard tick (Ixodes persulcatus)
Soft tick areare ventral and not visible from
Mouthpartsis leathery and lack the scutum ; above
 The body often wrinkled.
 Female and male have the similar appearance.




        Soft tick (Ornithodorus persicus)
 Harm to humans
Direct injures
1. Irritation: sting, secondary infection, allergy

2. Tick paralysis : paralysis of the motor nerves ---

   cannot walk or stand, has difficulty in speaking,

   swallowing and breathing.
 Harm to humans
Transmission of diseases

1. Tick-borne encephalitis/forest encephalitis
2. Xinjiang hemorrhagic fever
3. Tick-borne relapsing fever
4. Lyme disease
5. Babesiosis
6. tick-borne typhus
               Itch mite
   Sarcoptes scabiei parasitizes on humans,
which can cause scabies .
                    Pathogenesis
   Selects places where the skin is thin and wrinkled.
    between fingers, wrists, elbows, feet, etc.
in 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.
 Diagnosis
1. Symptoms:sinuous tracks in the skin, inflammation,
  itching;
2. Find the mites in the skin.
                    Dust Mite

Morphology:

   white to a light tan
   tiny, oval shaped
   covered with fine striations
  Dermatophagoides pteronyssinus 、
Dermatophagoides farinae and Euroglyphus maynei
are responsible for allergy.




     雌螨




                            D. pteronyssinus
     雄螨
                              (Der p)
   D. farinae(Der f)
Diagnosis
Serological tests: detect the serum antibody,
ELISA, skin test, etc.
            Insecta
mosquito
   fly
 sandfly
   flea
  louse
cockroach
          MOSQUITO
 There are more than 3300 species of mosquitoes
belong to 38 genera.
Piercing and sucking mouthparts.
 Slender proboscis.
               Antennae




Male: circular hairs   Female:circular hairs
are long and dense     are short and sparse
                   Labrum
                   Mandibles
                   Hypopharynx
 Proboscis
                   Maxilla
                   Labium




  The male lack of
mandibles and maxillas
   Anopheles sinensis
   Anopheles anthrophagus
   Anopheles minimus
   Anopheles dirus
       The most important vectors
    of malaria and Brugia malayi .

   Culex tritaeniorhynchus
       The most important vectors
    of epidemic B encephalitis.
Culex pipiens pallens

 C. p. quinquefasciatus

 The main vectors of W. bancrofiti
   Aedes albopictus
   Aedes aegypti
 The most important
 vectors of Dengue virus.
Flavivirus transmitted by
   Aedes mosquito
Illness varies from flu-like to
   severe hemorrhagic fever
Case fatality rate of up to
   20%
Fly
Fly and Diseases
Mechanical transmission:
Cholera , Typhoid fever, Bacillary dysentery , Amebic
dysentery, Helminthiasis



Biological transmission:
African trypanosomiasis
Bloodsucking flies:tsetse flies
                    Sandfly


   Medical important:

      Phlebotomus chinensis

Vector of Leishmaniasis(adult). sandfly fever,

Bartonellosis
                   Morphology
 Tiny, dark, hairy body
 Head: large black eyes, short sucking mouthparts,

         long antennae
 Thorax: humpback , erect V shaped

           position of the wings at rest.
                 Flea

   Ecto-parasite.

   Morphology:

    Brown-yellow color,

    Body is covered with bristle.
 Harm to humans
1. Irritation.

2. Parasitism( tungiasis)

3. Transmission of diseases

1) Plague: pathogen-Yersinia pestis

2) Hymenplepi diminuta

3) Dipylidium caninum
A flea (Xenopsy cheopis) taking a blood meal on a
human subject. Note that the flea lifts itself almost
vertically upward during the act of feeding.
Tungiasis
                    Louse
 Permanent ectoparasite.
 The parasitic lice of humans :

  Pediculus humanus: P. humanus capitis
    (2 subspecies)          P. h. humanus
  Pthirus pubis
    Morphology

Pediculus humanus

   Color:grayish,

   Wingless, 3 pairs of legs.

   Abdomen: male“V”,
             female“W”.
Pthirus pubis

   Smaller than Pediculus,

    2 mm in length.

   Body is broad with very
large claws on the middle
and hind legs.                耻阴虱
Harms to humans

     Pediculosis

 Symptoms: cutaneous irritation, loss of sleep
 and psychological depression.
               Cockroach




Periplaneta americana   Blattella germanica
Medical importance


   Mechanical vectors     carry various pathogens


   Intermediate host of hookworm larvae

   Cockroach allergens - children asthma

				
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