Sporozoa life cycle Plasmodium

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Sporozoa life cycle - Plasmodium

• 1.Oocyst forms in mosquito gut, mitosis forms
  sporozoites
• 2.Mosquito injects sporozoites, migrates into
  hepatocyte
• 3.Schizogeny (mitosis) of sporozoite results in
  merozoites, hepatocyte ruptures
• 4.Merozoites infect RBCs a) mitosis
  more merozoites to infect more RBCs (malaria) b)
  meiosis gametes injested by mosquitos
• 5. Gametes fuse to form zygote in mosquito gut.
• 6. Zygote encysts in mosquito gut to form oocyst
• Big differences weird, complex
• separate vector/host man skiter
• gt1 host cell type infected hepatocyte RBC
• troph (sporozoite) is NOT the primary
  pathogenic form
• asexual stage is infective/pathogenic stage
  ?

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Plasmodium life cycle see fig 20-2, pg.1124
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About helminths
Macroscopic? multicellular parasitic worms -
animals Size 2-3mm larvae to 10meter adults
(Taenia) Classification 3 groups in 2 phyla of
the animal Kingdom (Trematodes, Cestodes,
Nematodes) grouped by morphology of adult worm,
larvae and egg stages. Trematodes and Cestodes
are classes in the phylum Platyhelminthes
(flatworms). Nematodes are their own phylum
(roundworms vs annelids). Life cycle stages
adult worm, larvae egg - complicated by the
fact that multiple larval stages can exist.
Depending on the helminth, any of the 3 stages
can result in pathological changes in humans
next slide Nutrition aerobic heterotrophic
respiration ?
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Pathogenic helminth life cycle stages
Helminth egg larvae
adult 1. Trematode 2. Cestode
- 3. Nematode -
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Helminth taxonomy
Helminths are separated classified according
to general morphological characteristics and the
host organ they inhabit, e.g. lung flukes,
intestinal tapeworms, extra-intestinal
roundworms. They are all very prolific
egg-laying machines! Phylum Trematode flukes
are flat leaf-shaped worms with oral suckers (an
actual mouth, but a body cavity is lacking), and
ventral suckers (acetabulum) used as anchors to
help maintain their position. Reproduction is
hermaphroditic except blood flukes (Schistosomes)
which have 2 sexes (dioecious). The life-cycle
includes a snail intermediate host in which
asexual reproduction occurs. Sexual reproduction
occurs in the human definitive host. Clinically
significant flukes include blood flukes
(Schistosoma), liver flukes (Clonorchis,
Fasciola), intestinal flukes (Fasciolopsis) and
lung fluke (Paragonimus).
Images ?
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Adult liver flukes
Clonorchis Chinese liver fluke
Fasciola sheep liver fluke
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Helminth taxomony continued

• Phylum Cestode tapeworms are flat, elongated,
  segmented (redundant), strictly hermaphroditic
  flatworms that inhabit the intestinal lumen. Each
  segment is called a proglottid. All proglottids
  combined is the strobila. The head or scolex
  is fitted with suckers in 1 of 2 arrangements,
  and maybe also hooks to attach to the lumen wall.
  Larval forms inhabit extra-intestinal tissues
  while adults are lumen dwellers. Absence of an
  alimentary canal (scolex is NOT a mouth)
  nutrients must be absorbed through the tegument.
  Clinically significant intestinal genera include
  Taenia, Diphyllobothrium, Hymenolepis,
  Echinococcus and Dipylidium. Images ?

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Tapeworm images
?scolex?
Sections proglottids
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Helminth taxonomy continued

• Phylum nematode roundworms are cylindrical,
  non-segmented worms (vs Cestodes Annelids).
  They inhabit intestinal and extra-intestinal
  sites. More advanced having 1) a complete
  digestive system, and 2) reproductively
  dioecious meaning that male female organs are
  in separate individuals (males females),
  results in true sexual reproduction. Many
  nematodes are soil dwellers, some being plant
  parasites or parasites of other insects,
  including other nematodes!
• Clinically significant genera include Ascaris
  (night crawler!!!), Trichinella, Trichuris
  (whipworm), Necator Ancyclostoma (hookworms),
  Strongyloides, Enterobius (pinworm), Dranunculis,
  Capillaria and Trichostrongylus. Whipworm
  pinworm are exclusively intestinal. The other
  genera have both intestinal and tissue
  phases. Images ?

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Nematode images
Ascaris lumbricoides
Trichuris trichiura (whipworm)
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Nematode images
Necator
Enterobius eek!
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• On-line image quiz at

http//www.k-state.edu/parasitology/546tutorials/t
itlepage.html Read the intro. to parasitology
at http//gsbs.utmb.edu/microbook/intopara.htm
Other good sites http//gsbs.utmb.edu/microbook/t
oc.htm ?!!! http//www.k-state.edu/parasitology
/ ?!!! http//www.msu.edu/user/keasbria/Paraim
ages.htm http//www.edae.gr/parasitology.html a
nd there are lots more out there