1. Nematoda

2. Pseudocoelomates

3. Common Characteristics Pseudocoel –Mesoderm muscle lined ectoderm Complete digestive tract Organs are within pseudocoel Syncytial epidermis with non-living cuticle

4. Coelom

5. Phylum Nematoda Found everywhere Use pseudocoel as a hydrostatic skeleton –Collagen cuticle –Longitudinal muscles Free living and parasites Dioecious

6. Nematode Body Plan

7. Muscle Structure Longitudinal muscles –Parallel to ventral and dorsal nerve cords –Muscle cells form processes to associate with nerve cells –Muscles act against the hydrostatic skeleton

8. Muscle/Nerve Structure

9. Digestion and Metabolism Pharynx –Radial muscles Intestine –Single cell layer with no muscles –Body movement and ingestion moves food Parasitic nematodes often lack complete aerobic respiration

10. Nematode Parasites Ascaris (roundworms) –Found in intestine and lung. Hookworms –Attach to intestine and suck blood. Trichina worm –Forms cysts in muscle –Causes trichinosis Pinworms –Males are haploid, females diploid –Live in large intestine Filarial worms –Live in lymphatic system

11. Caenorhabditis elegans Extensively using in genetic and animal development research Lineage of each cells is know and documented Whole genome is cloned and sequenced

12. Family Ancylostomidae Hookworm –Ancylostoma duodenale –Necator americanus –Ancylostoma caninum

13. Ancylostoma cutting “teeth” Necator americanus Ancylostoma caninum

14. Male Copulatory Bursa

15. Ancylostomidae larval forms Rhbaditiform larva Filariform larva *infective form

16. Ancylostomidae

17. Family Ascarididae Humans –Ascaris lumbricoides Pigs –Ascaris suum Cats –Toxocara cati Dogs –Toxocara canis Cats and Dogs –Toxocara leonina

18. Ascaris lumbricoides

19. Ascaris Egg Development

20. Toxocara canis

21. Toxocara in situ Visceral organ migrans in intermediate host (rodent). Visceral organ migrans in humans is a dead end infection.

22. Toxocara cati Adults in intestine Heavy infection can cause intestinal blockage Toxocara cati

24. Toxocara transmission to young Toxocara cati –transmammary route to kittens. Toxocara canis –transplacental to fetus and transmammary route to puppies.

25. Strongyloides sterocoralis Homogonic cycle –Female is parasitic –Parthenogenesis Heterogonic cycle –Free living worms can mate in soil

26. Strongyloides stercoralis

27. Enterobius vermicularis Pinworm –Not very pathogenic only discomfort –Do not infect dogs or cats –Feed on epithelial cells and bacteria in intestine –Males are haploid, females diploid

28. Enterobius vermicularis

29. Male and Female Pinworms

30. Flat sided pinworm eggs

31. Dirofilaria immitis Dog and cat heart worm Transmitted through mosquitoes Most common in dogs Infects heart and lungs

32. Dirofilaria immitis in blood

33. Dirofilaria immitis in heart

35. Wuchereria bancrofti Causes Elephantitis Swelling and blockage of lymph ducts cause massive swelling in late stages

36. Trichinella spp. Domestic cycle –Pigs Trichinella spiralis Sylvatic cycle (hunting and eating wild mammals) –Temerate Zone Trichinella britovi Trichinella spiralis Trichinella murrelli –Tropic Zone Trichinella nelsoni –Arctic Zone Trichinella nativa

37. Trichinella spiralis

38. Trichinella spiralis in situ MuscleBlood

39. Phylum Acanthocephala Absorb nutrients through tegument Infect livestock, dogs and cats Requires invertebrate intermediate host –For example – beetle grubs are the intermediate host for pig infection

40. Proboscis –Everts and attaches to intestine