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HELMINTHS (Nematohelminthes (morphology (nemtode, epidermis, ridges, rings…

- - - - retention of L2 cuticle assists L3 survival
        
        direct life cycle
        
        eggs best 18-26°C
        
        high temps = faster development, but higher mortality as energy reserves deplete
        
        <10°C = won't hatch
      - most important cause of production loss
        
        young deaths
        
        growth rate
        
        carcass value
        
        ill thrift/death in adults
        
        treatment and management cost
      - abomasum
        
        Teladorsagia circumcincta (brown stomach worm)
        
        summer/autumn
        
        lambs
        
        diarrhoea, weight loss
        
        mucosal inflammation
        
        gastric secretory > unfunctional cells
        
        hypoproteinaemia due to protein leakage
        
        higher pH due to reduced acid secretion
        
        moult L3-L4 in gastric glands
        
        mature adults on mucosal surface
        
        Haemonchus contortus (barber’s pole worm)
        
        late summer
        
        lambs
        
        blood feeder
        
        anaemia
        
        hypoproteinaemia
        
        submandibular oedema
        
        ill thrift - death
        
        rarely scour
        
        Ostertagia ostertagi
        
        severe pathogology with adult emergence
        
        ML treatment
        
        competitive advantage to Cooperia oncophera and Nematodirus helvetianus
        
        similar lifecycle, mildly pathogenic
        
        immunity acquired, but slow
      - small intestine
        
        Trichostrongylus vitrinus (black scour worm)
        
        villous atrophy, mucosal hypertrophy
        
        just below mucosa
        
        effects on digestion, absorption, intake and utilisation
        
        autumn
        
        anorexia, dark scour, poor skeletal growth, wool quality, ill thrift, hypoproteinaemia
        
        Nematodirus battus
        
        coil round villi
        
        catarrhal inflammation
        
        May/June
        
        lambs
        
        acute onset diarrhoea, lethargy, abdominal pain, rapid weight loss, dehydration - sudden death
      - Type I - ingestion of large numbers of L3
      - Type II - emergence of arrested L4
      - Dictyocaulus viviparus (lungworm)
        
        aspiration pneumonia - death
        
        self cure over months
        
        reduced milk yield
        
        reinfection - immunopathology
        
        small infectious dose
    - - solid tissue feeders
        
        feed on mucosa plugs
        
        large buccal capsules - teeth, cutting plates, leaf crowns
        
        mostly intestinal
      - male copulatory bursa
      - large strongyles of horses Strongylus, Triodontophorus
        
        direct, migratory life cycle
        
        migration = pathology
        
        thrombus formation.
        
        inflammation/endoarteritis
        
        arterial wall thickens
        
        infarction, necrosis.
        
        fatigue, anorexia,
        ill thrift, colic
      - small strongyles of horses
        Cyathostomins
        
        direct, non-migratory life cycle
        
        catarrhal, heamorrhagic enteritis
        
        ill thrift, anaemia, diarrhoea.
      - ruminants
        Chabertia ovina
        
        colon
        
        direct life cycle
        
        adult mucosal feeding
        
        haemorrhage and protein loss
        
        often subclincial > parasitic gastroenteritis complex
      - Oesophagostomum dentatum - pigs
        
        caecum and colon
        
        direct life cycle
        
        L4 arrest in autumn
        
        adult mucosal feeding
        
        clinically rare
      - birds 'gapeworms’
        Syngamus trachea
        
        upper respiratory tract
        
        eggs in trachea, swallowed, pass in faeces
        
        mucus production
        
        haemorrhagic tracheitis
        
        pneumonia
        
        dyspnoea, depression, asphyxia ‘gaping’ - death
    - - browse on small intestine gut wall
      - thick walled eggs for environmental survival
    - - dogs, foxes, cats
        
        Ancylostoma
        
        direct life cycle
        
        prolific egg layers
        
        skin penetration
        
        pulmonary migration
        
        L4 swallowed > small intestine
        
        adults blood feed
        
        ingestion of L3
        
        pulmonary migration
        
        direct to small intestine
        
        migrate to skeletal muscle
        
        > reactivated during pregancy
        
        anaemia, diarrhoea, skin lesions
        
        Uncinaria
        
        ingestion of L3
        
        non-migratory
        
        penetrate skin, but won't develop
        
        diarrhoea, anorexia, lethargy
        
        hypersensitivity > digital dermatitis
      - ruminants
        Bunostomum
        
        direct lifecycle
        
        percutaneous
        or oral infection
        
        pulmonary
        migration
        
        severe anaemia,
        hypoalbuminaemia
        
        weight loss,
        ~ diarrhoea
        
        pruritis
      - small intestinal
        blood feeders
- - - - Dicrocoelium dendriticum
        
        adults in bile ducts
        
        eggs hatch in
        land snails
        
        cercariae in slime
        
        ants
        
        metacercariae
        
        1 more item...
      - Schistosoma
        
        blood
        
        atypical dioecious
        
        eggs pass through intestinal wall
      - Calicophoron daubneyi
        
        stomach
        
        metacercariae in duodenum
        
        immature plug feed
        
        forestomach
      - Fasciola hepatica
        
        egg
        
        miracidia
        
        snail
        
        cercariae
        
        vegetation
        
        1 more item...
        
        sub-acute
        
        liver parenchymal damage
        
        migrating immature flukes
        
        sudden death due to liver rupture
        
        Black disease
        
        fatal
        
        triggered by migrating flukes
        
        chronic
        
        hepatic fibrosis
        
        mature flukes in bile ducts
    - - indirect life cycles
        
        mollusc = (first) intermediate host
    - - miracidium
        
        (sporocyst)
        
        (redia)
        
        cercaria
        
        metacercaria
  - - - Taenia
        
        T. multiceps
        
        slow brain coenurus
        
        dog:sheep
        
        T. hydatigena
        
        liver > mesentery cysticercus
        
        sheep
        
        T. ovis
        
        heart/diaphragm cysticercus
        
        dog:sheep
        
        T. saginata :warning:
        
        human:cattle
        
        muscle cysticercus
        
        T. solium :warning:
        
        human:pigs
      - Echinococcus
        
        E. granulosus
        
        ochospheres survive <2 years
        
        lung/liver hydatids
        
        hydatids
        
        sudden death due to anaphylactic shock from rupture
        
        'hydatid sand'
        
        E. multilocularis :warning:
        
        wild canids:rodents
        
        multilocular hydatids
        
        metastatise
      - Monezia
        
        M. expansa
        
        sheep:oribatid mites
        
        cysticercoid
      - Dipylidium
        
        dog/cats:fleas/lice
        
        cysticercodes in abdominal cavity
        
        D. caninum
        
        Cteno. fleas
        
        only larvae can ingest
        
        Tricho. lice
        
        all stages can ingest
      - Anoplocephala
        
        horses:mites
        
        jejunum
        
        intestinal obstruction/perforation at ileocaecal junction
        
        ulceration of intestinal mucosa
    - - larvae form cysts
        
        adults in final host gut
    - - scolex (head)
      - strobilla of proglottids
        
        self contained egg producing units
        
        hermaphrodite
        
        eggs detach and crawl/are expelled in faeces
      - no gut
        
        nutrients absorbed through body wall
    - - onchosphere
        
        contains larva
      - thick walled
        
        prevent desiccation
    - - hexacanth
        
        burrows through gut mucosa
        
        enters blood/lymph
      - metacestode
        
        cysticercoid
        
        invertebrate solid cyst
        
        Hydatid
        
        protoscoleces detached within
        
        Coenurus
        
        many invaginated protoscoleces
        
        Cysticercus
        
        fluid filled sac one protoscolex
- - - - adult parasitic stages
    - - immature stages
    - - immature stages taken up, not retained, no development, not essential hosts
    - - immature stages retained, no development, not essential hosts