Parasitology MT 1

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Parasitology MT 1
2014-04-20 21:04:41
nematode parasite life cycle parasitology

ENT 156 Sp 2014
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  1. Pinworm Life cycle
    • Direct life cycle
    • -gavid female migrate to perianal to deposit
    • -become infective in 4-5 hours, (retroinfection)
    • -eggs are distributed through linens, air, scratching
    • -infected eggs eaten by human
    • -hatch in small intestine
    • -larvae migrate to colon (restart cycle)
  2. Pinworm name
    Enterobius vermicularis
  3. Pinworm Info
    • Human only
    • Eggs are short lived
    • Killed by drying
  4. Pinworm symptoms
    • 1/3 of infections are asymptomatic
    • -Perianal itching
    • -secondary bacterial infections
  5. Complications of pinworms
    • inflammed appendix
    • invasion of female genital tract
  6. Diagnosis of pinworms
    • few eggs in feces
    • scotch tape test right after waking up (3 days in a row)
  7. Treatment of pinworms
    • anthelminthics for entire family
    • doesnt kill all larvae
    • best to treat two weeks after first treatment
  8. Ascariasis
    Ascariasis lumbricoides

    • very rare in US, most in africa and asia
    • Pig species is A. suum
  9. Ascariasis life cycle
    • DIRECT
    • -eggs passed to soil
    • -2-4 weeks to become infective
    • -human ingest
    • -larva hatches in small intestine
    • -penetrates mucosa and bloodstream (8-18 hr)
    • -migrates to lung then back down to small intestine. become adults and reproduce
  10. Ascariasis requirements
    • poor sanitation and fecal contamination
    • extremely resistant to chemicals, not UV though
  11. Ascariasis symptoms
    • depend on intensity
    • about 10 worms means abdominal pain, can lead to intestinal blockage
  12. Ascariasis Diagnosis
    • direct fecal exam (easy due to amount of eggs produced)
    • passing adults in feces
    • fever can cause migration
  13. Ascariasis treatment
    • anthelmenthics
    • partial intestinal obstruction- slow dose anthelmentics
    • complete obstruction- surgery
  14. Visceral Larval Migrans characteristics
    prolonged fever, persistent eosinophilia, potential eye damage, pneumonitis
  15. Cause of VLM
    Toxacara canis or cati
  16. VLM life cycle
    • -egg in feces
    • -J3 ingested by rodent, human, dog
    • -in human causes VLM, in rodent its paratenesis, and dog is where it matures.
    • -juveniles enter alveoli and mature
    • -adult worms mate in small intestine
    • -could lead to transplacental transmission to pup (cycle)
  17. Diagnosis of VLM
    • since no adults in humans, no eggs in feces
    • Elisa test
    • MRI abnormality in brain
  18. Treatment of VLN
    • anthelminthic plus anti inflamatory
    • once J3 in CNS tissue, anthelminthics are useless
  19. prevention of VLM
    • Deworm puppies and kitten
    • clean up after pets
    • cover sandboxes
  20. Dracunculiasis (Guinea Worm)
    • Drucunculus medinensis
    • infects dogs, cats, horses, cattle, primates
    • Focus of global eradication effort
  21. Dracunculiasis
    • Only human nematode transmitted through drinking water
    • Female worms emerge from skin
    • where there's limited drinking water
    • symbol of medicine
  22. Dracunculiasis life cycle
    • Humans drink unflitered water containing copepods with J3
    • J3 released, mature and reproduce in small intestine
    • fertilized female migrates to skin, causes blister, discharges larvae
    • J1 released into water, consumed by copepod
    • J1->J3 in copepod (Cycle)
  23. Treatment of Dracunculiasis
    • No effective drug treatment known, some anti-inflammatories help
    • surgery when worm is in appropriate area
    • worm on stick to remove
  24. Dracunculiasis control
    • Prevent human entry into drinking water sources, isolate infected
    • Kill copepods with Abate
    • Filter water
  25. lymphatic filariasis
    • Wuchereria bancrofti (Only humans)
    • Brugia malayi (Cats and monkeys)
  26. Life cycle of Lymphatic filariasis
    • Mosquito ingests microfilariae when biting human
    • ingested MF develop into filariform juveniles
    • infected mosquitoes transmit filariform juvenile to human
    • juveniles migrate via lymphatics to regional lymph nodes
    • mature to adult worms in afferent lymphatic vessels and reproduce
    • microfilariae migrate to blood stream (cycle)
  27. Filarioidea - Generalized life cycle
    • Female worms ovoviviparous (live bearing, eggs hatch within), produce microfilaria
    • Mosquito has to feed twice in order to transmit
    • Symptoms due to adults
    • Nocturnal periodicity (10pm-2am)
  28. Biological vectors of Lymphatic filariasis
    • W. bancrofti: anopheles, culex, aedes
    • b. malayi: Mansonia

    Requires 6-20 days to develop in vector, depends on mosquito
  29. Clinical phases of Lymphatic filariasis
    • Pre-patent period: 6-12 months
    • Asymptomatic phase: microfilaria in blood by no response from immune system
    • Acute phase: chills, fecer, swelling, inflammation
    • Obstructive phase: (YEARS) hydrocoele (testes), chyluria, elephantiasis
  30. Diagnosis of lymphatic filariasis
    • Blood sample, requires proper sampling time of blood
    • Some infected produce no microfilaria in blood
    • ELISA test
  31. Treatment of lymphatic filariasis
    • community based treatment
    • DEC against adults and microfilaria
    • Ivermectin kill MF only
    • surgery
    • Control: DEC + albendazole 2 yearly dose reduces MF
  32. Onchocerciasis
    • River blindness
    • Onchocerca volvulus (Only humans)
    • LC like filariasis (INDIRECT) but with black fly vector and development short
    • Damage due to juveniles
  33. onchocerciasis Variation in disease presentation
    • Africa: arms, thighs, trunks (lowland and forest disease)
    • Central and south america: associated with coffee growing, tend to bite head due to limited skin exposure.
  34. Features of onchocerciasis
    • MF remain primarily on skin
    • symptoms mainly due to MF
    • inflammation due to cell mediated reactions against MF
  35. onchocerciasis infections
    • Prepatent period up to a year
    • SKIN ITCHING, abnormal pigmentation, loose, thickening, Hanging groin
    • Photophobia, sensation of foreign body in eye, eventual eye lesions
  36. Diagnosis of Onchocerciasis
    Skin snips, Mf will swim out of skin into saline
  37. Treatment of Onchocerciasis
    • Field removal
    • anthelminthic
    •   Ivermectin (acts slowly, inhibits MF)/DEC
  38. plant root parasite classification
    • ectoparasites: adult remains outside root but feeds on root tissue stylet
    • endoparasites: migratory-move through plant tissue. sedentry- stays at one site

  39. Root-knot nematodes
    • Meloidogyne
    • most important plant parasites with respect to economic impact
    • elicits root border cell defense which paralyze nemas
  40. life cycle of Meloidogyne
    • J2 hatches from egg, is attracted to root zone
    • J2 penetrates root, migrates between cells
    • Female induces giant cell formation in root
    • Eggs deposited in gelatinous matrix
  41. Symptoms of infection from meloidogyne
    stunted growth, yellow leaves, wilting, reduction in root number, root galls
  42. Entomophathogenic nemas (EPN)
    • nemas that quickly kill their insect host
    • Steinernmema
    • Heterorhabditis
    • effective for biological control of insects with a growth stage in soil
  43. EPN bacterial system
    • suppress insect immune system
    • produce toxins that kill infected host within hours
    • digest insect cadaver
    • produce antibiotics that reduce growth of other microflora
    • produce pigments/light
  44. Heterorhabditis
    • nemas are hermaphrodites, 1 J3 can start infection
    • adhere to nema intestinal surface
    • has cuticular tooth in J3
  45. Steinernema
    • Xenorhabdus
    • requires 2 J3
    • no cuticular tooth
    • enters through natural body openings