Parasitology Lecture: Nematodes of Equine Ruminants and Swine

  1. Nematodes of Equine taxonomy
    • Phylum: Nematoda
    • Order: Strongylida
    • Family: Strongyloidea
    • Sub-family: Cyathostominae and Strongylinae
  2. Sub family Cyathostominae of equine AKA
    Small strongyles
  3. Sub family Strongylinae of equine AKA
    Large strongyles
  4. Large strongyles AKA
    • Bloodworms
    • Redworms
  5. How many species of large strongyles are there?
  6. 3 common large strongyles
    • Strongylus vulgaris, smallest most dangerous
    • Strongylus equinus
    • Strongylus edentatus
  7. Most common cause of colic and death in TX?
    Parasites, Strongylus vulgaris most common
  8. Strongylus vulgaris prepatent period
    6 months
  9. Migration of Strongylus vulgaris
    • S3 larvae ingested
    • S3 cast its covering and enters wall of cecum and ventral colon
    • Larvae penetrates submucosa and molts to S4 in one week
    • S4 penetrates small arteries and aorta, then wander progressively through to the cranial mesenteric artery in 11-21 days 
    • After 2-4 months S4 enters surrounding tissue and molt to S5 which enters the lumen of colon, reproduction occurs in a couple months
  10. Treatment for Strongylus vulgaris
    • Ivermectin 
    • Albendazole
  11. How does Strongylus vulgaris cause colic?
    Movement of S4 results in inflammation of arteries resulting in thrombosis and moving clots (embolism) that block flow of blood to intestines resulting in death of the intestines and no movement of enteric contents
  12. Domestic animals can develop _____ due to colic
    • Collateral arteries to carry the blood. 
    • Brief stoppage can be treated with Banamine (pain medicine) and Mineral oil
  13. Seatworm of man
    • Enterobius vermicularis 
    • Inhabits appendix, large intestines and female genitalia
  14. Strongylus edentatus migration
    • S3 larvae burrows into wall of gut and reaches liver via portal veins 
    • Larvae make way back to cecum and into bowel lumen
  15. Strongylus equinus migration
    • S3 larvae molts in intestinal wall
    • S4 goes to right half of liver then cecum
    • 4th molt occurs 4 months later and adults enter lumen of large intestines to reproduce
  16. How many species of small strongyles?
  17. Do small strongyles migrate viscerally?
  18. Difference between small strongyles and large strongyles
    Small strongyles burrow in intestinal wall and lay dormant, during this encysted period dewormers will not work and can cause chronic infection
  19. Equine pinworm
    Oxyuris equi
  20. Pin worms of equine AKA
    • Rectal worm
    • Nocturnal worm
  21. Taxonomy of equine pinworms
    • Phylum: Nematoda
    • Order: Ascaridae
    • Family: Oxyuroidea
    • Genus: Oxyuris, Enterobius, Probstymarea
  22. Oxyuris equi inhabits which part of the body?
    • Cecum/colon
    • Direct life cycle
  23. What does Oxyuris equi cause?
    Pruritis ani, eggs attach to skin around anus causing itching and rubbing of tail
  24. Oxyuris equi egg facts
    • Female migrates down colon and rectum out through anus to cement her eggs in masses to skin of the anus
    • Eggs contained in yellowish grey fluid which dries, cracks and detaches from skin in flakes
    • Single operculated egg
  25. Minute pinworm of equine
    • Probstmayria vivipara
    • Viviparous
    • Life cycle completed entirely in intestines, females produce sexually mature offspring
  26. Ascarid of the horse
    Parascaris equorum
  27. Ascarid of the horse taxonomy
    • Phylum: Nematoda
    • Order: Ascaridae
    • Family: Ascaridoidea
    • Genus: Parascaris
  28. Parascaris equorum migration
    Trans tracheal
  29. Parascaris equorum facts
    • Largest ascarid
    • Resistant to weather and environment
    • Found in anterior part of small intestines 
    • Infection in young can lead to death through telescoping of intestines
    • S2 is the infective stage
  30. Gasterophilus common species
    • Gasterophilus intestinalis
    • Gasterophilus nasalis
    • Gasterophilus haemorrhoidalis
  31. 3 stages of Gasterophilus species
    Fly-Egg-Larvae=  1 year
  32. Gasterophilus intestinalis life cycle
    • Eggs on forelegs/shoulder 
    • After 5 days eggs consumed and move to tongue for 1 month
    • Moves to duodenum for 11 months
  33. Gasterophilus nasalis life cycle
    • Eggs laid on inter mandibular spaces
    • Eggs hatch in 5 days and move into pockets between molars for 1 month
    • Move to duodenum for 11 months
  34. Gasterophilus haemorrhoidalis life cycle
    • Eggs laid on lips
    • 2-4 weeks hatch and penetrate epidermis of lips and burrow in mucus membranes of mouth for 1 month
    • Move to duodenum for 11 months
  35. Medications used to remove bots
    • Carbon disulfide "Parvex Plus"
    • Dichlorvos "Equigard" Organophosphate
    • Trichlorfon "Combot" Organophosphate 
    • Ivermectin "Ivermec" Drug of choice
  36. Intestinal threadworm of equine
    • Strongyloides westeri 
    • In small intestinal mucosa
    • Effects pigs also
    • Passes usually as eggs
  37. Minute stomach worm of equine
    • Trichostrongylus axei 
    • Lives in abomasum
    • Infection results in ulcers, weight loss, anorexia, death 
    • Zoonotic
  38. Equine stomach worms AKA
    Summer sores
  39. 4 common equine stomach worms
    • Habronema muscae
    • Habronema majus
    • Habronema microstoma
    • Draschia megastoma
  40. Genus of coccidia in farm animals
  41. Habronema and Draschia 2 ways to transmit
    • Larvae on skin invade tissue and cause summer sore, associated with Musca domestica and Stomoxys calcitrans 
    • Flies are consumed and enter GI tract and produce catarrhal gastritis with mucus production
  42. Stomach worms of ruminants taxonomy
    • Phylum: Nematoda
    • Order: Strongylida
    • Family: Trichostrongyloidea
  43. 4 common stomach worms of ruminants
    • Trichostrongylus axei
    • Haemonchus contortus
    • Haemonchus placei
    • Ostertagia ostertagi
  44. Stomach worms on ruminants are found in what part of the body?
  45. Transmission of stomach worms of ruminants
    • Female lays eggs in abomasum and pass and develop into larvae
    • Crawl up blades of grass and consumed
    • 2 molts in body, mature adults reproduce 
    • Life span is 1 year
  46. Intestinal worms of ruminants (2)
    • Bunostomum phlebotomum- cattle
    • Bunostomum trigonocephalum- sheep/goat
  47. Transmission of intestinal worms of ruminants
    • Skin penetration
    • Swallowing of larvae
    • Transmammary
    • InUterine
  48. Nodular worms of ruminants (2)
    • Oesophagostomum columbianum- sheep
    • Oesophagostomum radiatum
  49. Common lungworms of ruminants
    • Dictyocaulus viviparous
    • Dictyocaulus filaria
    • Muellerius capillari
  50. Disease caused by lungworms in ruminants
  51. Metastrongyles use what as intermediate host?
    Earthworm or snail
  52. Protostongylus rufescens can inhabit what part of the body in other species?
    Circulatory system
  53. Lungworm of ruminants life cycle
    • Eggs laid in lungs, hatch or passed intact
    • Eggs coughed up, swallowed and passed
    • Eggs hatch in soil, larvae consumed
    • Larvae penetrate intestines, to the blood then to the lungs
  54. Roundworm of swine
    Ascaris suum
  55. Largest nematode of human intestines
    • Ascaris lumbricoides
    • 25% of population test positive
  56. Life cycle of Ascaris suum
    • Eggs consumed, hatch, larvae penetrates intestines
    • Larvae enters hepatic circulation, goes to lungs and migrate
    • Larvae coughed up by trachea and returns to intestines
    • Adults breed and produce eggs, eggs pass out and incubate in soil
  57. Terms used only for the pig
    • Milk spots- liver
    • Thumps- lungs
  58. Atropic rhinitis in pigs AKA
    Bordetella bronchiseptica
  59. How do Ascaris suum and Ascaris lumbricoides feed?
    Obtain nourishment by contents of pig/human intestines, dont feed on mucosal lining
  60. Common kidney worm of swine
    • Stephanurus dentatus 
    • Direct and Indrect life cycle (earthworm)
    • 2nd most common parasite in pigs
    • Eggs passed in urine, larvae may penetrate pig, be consumed, or picked up by earthworm
  61. Intestinal parasites of swine
    • Strongyloides westeri
    • Strongyloides suis
    • Strongyloised ransomi
  62. Transmission of intestinal parasites of swine
  63. Symptom of intestinal parasites of swine
    Bloody diarrhea
  64. Stomach worm of swine
    • Physocephalus sexalatus 
    • Ascarops strongylina
  65. Swine cestode
    • Macracanthorhynchus hirudinaceus
    • Thorny headed worm
    • Uses dung beetle, maybeetle and water beetle as intermediate host for 3 months
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Parasitology Lecture: Nematodes of Equine Ruminants and Swine
Nematodes continued