1. Nematoda VMP 920 Infection & Immunity II Veterinary Parasitology

2. Ancylostoma caninum Canine Hookworm DZ Morphology Dimorphic Male (bursate) & Female Nematodes Hooked anterior, buccal cavity, & teeth

3. Dimorphic Male & Female Males with copulatory bursa Hooked anterior, buccal cavity, & teeth

4. Life Cycle Life cycle image

5. Life Cycle Direct Life Cycle (Canine – Small Intestine) Transmission From eggs to infective L3 in 5-7 days Skin / oral penetration of infective larvae (L3) Ingestion of paratenic host with encysted L3 Arrested (hypobiotic) larvae in host tissue Transmammary infection of puppies Source for chronic hookworm DZ, role of premunition & “larval leak” 3 week prepatency

6. Life Cycle competent

7. Life Cycle pregnancy

8. Life Cycle puppy

9. Life Cycle chronic

10. Pathology Hemorrhagic anemia Peracute, Acute, Chronic DZ Zoonosis: Cutaneous Larval Migrans Eosinophilic Gastroenteritis

11. Pathology Hemorrhagic anemia

12. Pathology: Zoonosis Cutaneous larval migrans

13. Clinical Signs & Diagnosis Signs of anemia, edema, tarry feces, pale mucus membranes, bloody diarrhea Check mucous membranes in young puppies Fecal Centrifugation

14. Clinical Signs & Diagnosis Pale Mucous membranes Hookworm eggs on Fecal Exam (absent on peracute cases)

15. Treatment Fenbendazole, Ivermectin Peracute – deworm immediately, may need iron supplement & blood transfusions. Deworm weekly due to re-infection via transmammary transmission.

16. Treatment Acute – (puppies) treat at 2-3 weeks old and repeat treatment every 2 weeks until 2 months (start of heartworm prevention program) Chronic – test & treat Treat pregnant female near parturition to target reactivated larvae. (Ex. daily from fortieth day of gestation to fourteenth day of lactation)

17. Control Sanitation of environment, runs, kennels, etc. Assume infection, especially puppies but also older animals. Choose Heartworm preventative that also kills hookworms Regularly scheduled fecal tests, treat as needed. Prevent access to paratenic hosts.

18. Important Points Direct Life Cycle – L3 penetration & ingestion  Sanitation of environment & by deworming. Special life cycle concerns: Prepatent period, Arrested larvae, Transmammary Transmission, Paratenic host, Premunition + Deworming = “Larval Leak” Blood feeding worms  Pathology (anemia) (Peracute, Acute, Chronic)

19. Important Points Diagnostics: Fecal exam, response to treatment, assume infection in puppies, clinical signs Treatment / Control: Understand treatment plan in puppies Treatment / Control: Understand treatment plan in pregnant dogs. Zoonotic Concern

20. Important Points Challenges to Controlling Infection Sanitation Arrested (hypobiotic) Larvae Transmammary Transmission “Larval Leak” Paratenic Host

21. Toxocara canis Canine Ascarid (Toxocariasis) Dimorphic Male (non-bursate) & Female Nematodes Large worm, 3 fleshy lips, cervical alae

22. Large worms, Dimorphic Male & Female Males are non-bursate, hooked tail & spicules for copulation 3 fleshy lips cervical alae

23. Life Cycle Life cycle image

24. Life Cycle Direct Life Cycle (Canine - Small intestine) Transmission -- ingestion of infective egg From eggs in feces to infective egg in 4 weeks Very resistant & long-lived egg Tracheal migration in puppies Somatic migration in older dogs

25. Life Cycle Arrested (hypobiotic) larvae in host tissue Transuterine infection of puppies Very minor contribution via Transmammary infection Ingestion of paratenic host w/ Arrested larvae

26. Life Cycle Prepatency Via egg ingestion: 4 to 5 weeks Transuterine: 3 week prepatency

27. Life Cycle Paratenic Host

28. Life Cycle competent

29. Life Cycle pregnancy

30. Life Cycle puppy

31. Pathology Gastroenteritis Zoonosis: Visceral / Ocular Larval Migrans

32. Pathology Gastroenteritis

33. Pathology: Zoonosis Visceral larval migrans in humans also Ocular larval migrans

34. Clinical Signs & Diagnosis Abdominal pain, potbellied conformation, poor coat condition, fetid mucoid diarrhea Adult worms in feces or vomit Worm eggs in fecal exam

35. Pot-bellied conformation

36. Clinical Signs & Diagnosis Toxocara egg on Fecal Exam

37. Treatment Fenbendazole, Ivermectin Treat (puppies) at 2-3 weeks old and repeat treatment every 2 weeks until 2 months (start of heartworm prevention program) Treat pregnant female near parturition to target reactivated larvae. (ex. daily from fortieth day of gestation to fourteenth day of lactation)

38. Control Sanitation of environment, runs, kennels... Assume infection in puppies Choose Heartworm preventative that also kills ascarids (Toxocara) Prevent access to paratenic hosts.

39. Important Points Direct Life Cycle – ingestion of ova  Sanitation of environment & by deworming. Special life cycle concerns: Prepatent period, Arrested larvae, Transuterine Transmission, Paratenic host Pathology -- Gastroenteritis

40. Important Points Diagnostics: Fecal exam, assume infection in puppies, Clinical Signs Treatment / Control: Understand treatment plan for puppies Treatment / Control: Understand treatment plan for pregnant dogs. Zoonotic concern

41. Important Points Challenges to Controlling Infection Sanitation (long-lived very resistant eggs) Arrested Larvae. Transuterine Transmission Paratenic Host