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Fascinating World of Parasites: Adaptations in Platyhelminthes Zoology

Explore the intriguing world of parasitic adaptations in Platyhelminthes, focusing on their methods of attachment, osmotic pressure, reproduction, and impact on hosts. Learn about trematodes, monogenea, and cestoda, their anatomy, life cycles, and host specificity variations. Discover the unique strategies these parasites employ to survive and reproduce.

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Fascinating World of Parasites: Adaptations in Platyhelminthes Zoology

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  1. ZOO 115 Invertebrate Zoology Platyhelminthes Parasites

  2. SUCKERS AND HOOKS - Cestoidea home.earthlink.net/~xylaria/em/tapeworm.jpg www.icr.org/research/ma/images/ma-r01-f12.jpg Parasitism - Adaptations • Method of attachment • SUCKERS - Trematoda and Monogea

  3. static.howstuffworks.com/gif/mosquito6a.jpg a.abcnews.com/images/2020/pd_eating_070521_ms.jpg Parasitism - Adaptations • Getting into host • Penetration – special glands to digest skin • Getting into host • Passive – eaten by host • Need outer resistant covering • Living tegument • Permeable to H20, amino acids, sugars • Tolerate great changes in pH.

  4. Parasitism - Adaptations • Osmotic Pressure • Must be lower than surroundings – why? • Facultative anaerobic respiration • 4X more efficient than in vertebrates • Reduced structures • Sensory (except chemo) • Muscles • Nervous system • Digestive tract

  5. Parasitism - Adaptations • Increased reproduction • Produce many many eggs • e.g. Fish tapeworm 2 million eggs/day and can live for 15 yrs (100 trillion eggs in lifetime) • Polyembryony – many young from one egg. • Asexual stages amplify numbers • e.g. Fasciola hepatica produces 500,000 eggs in a lifetime that produce 42 trillion offspring.

  6. www.semioticon.com/seo/M/images/mimicry_2.jpg Parasitism - Adaptations • Host reactions to parasites • Susceptibility varies with life cycle and health of host • Single host – parasite usually becomes more commensal • Castration • Multiple hosts – parasite can kill the host • Snails • Ants • Internal parasites – develop ways of hiding from immune system

  7. Parasitism - Adaptations • Host specificity varies • Some are completely specific to their hosts • Problems with non-specificity • Swimmer’s itch • Nematode and encephalitis

  8. Class - Trematoda • Common Name - Flukes • Common parasites of all major vertebrate taxa. • >11,000 species

  9. web.bio.utk.edu/guffey/BiaB Class Trematoda - General Anatomy of Adult • Suckers for feeding and attachment • Non-cliated tegument • Protection against enyzmes, • Gas exchange • Eliminate nitrogenous waste • Absorb glucose and amino acids

  10. www.cat.cc.md.us/courses/bio141/labmanua/lab22/images www.cat.cc.md.us/courses/bio141/labmanua/lab22/images Class Trematoda - General Anatomy of Adult

  11. Class Trematoda – Life Cycles • Chinese Liver Fluke (Opisthorchis or Clonorchis) • Infests 20 million E. Asians • Adult ~ 2.5 cm in length • Live 8 yrs • Produce 4000 eggs per day for 6 mo • Symptoms: Jaundice, gallstones, debilitation and liver cancer

  12. Amplification Adult Redia Miracidium Sporocyst Cercaria Metacercaria ucdnema.ucdavis.edu/imagemap/nemmap/ent156html/slides www.biology.ualberta.ca/courses.hp/zool250/Labs/Lab05/ /www.spelman.edu/~biology/bio112/lab/images bio.winona.msus.edu/bates/Parasitology/Images/ Cercaria biodidac.bio.uottawa.ca/ftp/BIODIDAC/Zoo/Platyhel/DIAGBW www.cdc.gov/ncidod/eid/vol5no5/images ucdnema.ucdavis.edu/imagemap/nemmap/ent156html/slides Class Trematoda - Life Cycle

  13. Male Female /www.biology.ualberta.ca/courses.hp/zool250/Labs Class Trematoda – Life Cycles • Blood Fluke (Schistosoma sp) • Dioecious: Male 6-10 mm, Female much smaller (fits into groove in male) • Develop cercaria directly from sporocyst (no redia)

  14. Class Trematoda - Reproduction • Why is amplification important? • What impact might the multiple host strategy of the parasite have on the hosts?

  15. www.pubs.royalsoc.ac.uk/proc_bio_content/images/ bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-4a/Class_Monogenea http://www.paru.cas.cz/helminti/Monogenea.html Class Monogenea • Ectoparasites – only one host • Mostly infest fishes • Adults have suckers and hooks • Larvae – hooked free-swimming (oncomiradium)

  16. www.chilternkoi.nildram.co.uk/ Class Monogenea – life cycles • Dactylogyrus sp. • More eggs with increasing temperature • Eggs released – sit on bottom • Hatch into swimming larvae • On contact with fish metamorphose into adult form

  17. www.biology.ualberta.ca/courses.hp/zool250 Class Monogenea – life cycles • Polystoma sp. • Eggs stay in frog until frog gets in water • Hatch into swimming larvae • Larvae attach to gills of tadpoles • Tadpoles metamorphose and larvae crawls over belly and goes into bladder

  18. faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files Class Cestoda • Common name: Tapeworms • ~3400 species • Gut is absent – specialized neodermis for nutrient uptake. • Live about 15-20 yrs • Can copulate

  19. Scolex news.bbc.co.uk/media/images/ Hooks Suckers Neck www.personal.psu.edu/users/t/r/trp2 www.microscopyu.com/galleries/smz1500/images www.scoop.co.nz/stories/images www.ibiblio.org/herbmed/eclectic/thomas/pics Class Cestoda - Anatomy • Can reach 15 m in length! • Head region • Attach to prey’s intestinal tract

  20. biodidac.bio.uottawa.ca/ftp/BIODIDAC/ZOO/PLATYHEL/PHOTO/ www.personal.psu.edu/users/t/r/trp2 www.ibiblio.org/herbmed/eclectic/thomas/pics Class Cestoda - Anatomy • Proglottids • Each is a complete hermaphroditic reproductive system • Both Cross and Self-Fertilization

  21. http://wdfw.wa.gov/wlm/regions/reg5/graphics/tapeworm.jpg biodidac.bio.uottawa.ca/ftp/BIODIDAC/ZOO/PLATYHEL/PHOTO/ www.path.cam.ac.uk/~schisto/Pictures/Eggs/Other_helminth_eggs bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-4b/ Class Cestoda – Life Cycles

  22. users.rcn.com/jkimball.ma.ultranet/BiologyPages/ Class Cestoda – Life Cycles • If eggs go in water • swimming larvae (onchosphere) hatches within 10 days • Eaten by copepods • Copepods eaten by fish • Penetrates gut, migrates to muscle and transformed into dormant miniaturized adult • Eaten by warm-blooded host

  23. Class Cestoda – Life Cycles • If eggs go on land • Eggs eaten by cattle • Onchosphere larvae hatch, bore into intestinal wall and transported through circulatory system to muscle tissue • Develops into bladderworm larvae (Cysticercus). • Eaten by warm-blooded host. http://sps.k12.ar.us/massengale/tapeworm.gif

  24. Class Cestoda • Causes Diarrhea, Weight loss and inflammation • Biggest problem is accidental infestations • Bladder worm will develop into tissue other than muscle. • Cyst can contain liters of fluid which could cause severe infection if released

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