1. Parasitology

2. Monday March 23, 2015
What is an endoparasite? Can you think of an example of an endoparasite?
What is an ectoparasite? Can you think of an example of an ectoparasite?

3. Introduction Endoparasites Ectoparasites Nematodes Cestodes Trematodes
Protozoa
Ectoparasites
Ticks, fleas, lice, mites, biting flies

4. Signs of parasites Diarrhea Vomiting Anemia Intestinal obstruction
Malnutrition (hypoproteinemia)
Lack of weight gain
Milk production
(itching)

5. Transmission Direct Transport hosts (intermediate host)
Often fecal-oral route
Transport hosts (intermediate host)
Organism completes a development stage
Short transitory period
Definitive host (primary host)
Lives, reaches maturity, reproduces

6. Endoparasite “families”
Nematodes
Cestodes
Protozoa

7. Nematodes Roundworms Esophageal worms Stomach worms Ascarids Hookworms
Intestinal threadworms
Whipworms
Pinworms
Heartworms

8. Roundworm characteristics
Live and move about in tissues
Intestines, lungs, kidneys, urinary bladder, muscle, blood
Eggs and larvae most commonly found in the feces
Intestinal
Ascarids
Hookworms
Whipworms

9. Nematodes - Ascarids Toxocara species (spp) Eggs Stages
Toxocara canis, Toxocara cati
Eggs
Large, round – oval, dark colored, thick shell
Stages
Eggs are ingested
Hatch in small intestine
Larvae penetrate mucosa of intestine, migrate through tissues (liver/heart/lungs)
Larvae are coughed up and swallowed and make way back to intestine

10. Adult Worm

11. Eggs under microscope

12. Prenatal/transplacental migration of T. canis
Larvae leave the circulation and are stored in tissues/organs
Dog becomes pregnant
Larvae leave the tissues at day of gestation
Cross placenta and enter lungs of fetuses
Puppies are born with the larvae in their lungs and cycle continues as the larvae mature and enter intestines
T. canis and T. cati : some larvae migrate to mammary glands and are ingested by puppies and kittens when they nurse

13. Zoonosis of Toxocara Eggs are ingested by small child
Larvae hatch and migrate through liver, lungs, eyes
Called visceral larva migrans

14. Visceral Larva Migrans

15. Medication for ascarids/ roundworms
Fenbendazole, milbemycin oxime, moxidectin, and pyrantel pamoate
Pyrantel is available in a highly palatable liquid formulation that is readily administered to nursing animals and thus may be considered the preferred treatment for very young pups.
To prevent environmental contamination, all pups should be routinely treated with pyrantel pamoate at 2, 4, 6, and 8 weeks of age and then placed on a monthly heartworm preventative with efficacy against Toxocara spp.

16. Roundworms and hookworms (pyrantel)

17. Symptoms of “Roundworms”
Cough
Shortness of breath
Abdominal pain
Pot bellied appearance
Nausea and
Diarrhea
Blood in the stool
Weight loss
Dull coat
Fatigue
Presence of the worm in vomit or stool

19. - Hookworms Ancylostoma species or Uncinaria stenocephala Eggs
Oval, thin shelled

20. Stages Eggs are passed into environment
Develop and hatch in environment
Larvae are ingested or penetrate skin
Enter veins (circulatory system) into the lungs
Coughed up and swallowed
Enter small intestine and mature
Transplacental and transmammary migration also

21. Nematodes - Hookworms

22. Zoonosis of Hookworms
Cutaneous larva migrans

24. Nematodes - Whipworms Tricherus Vulpis Eggs Stages
Thick brown yellow shell with a clear polar plug at each end
Stages
Eggs are ingested
Larvae hatch into small intestines
Penetrate mucosa, migrate and return to intestines
Migrate to cecumand colon and bury their anterior ends into the mucosa and mature to adult stage

25. Whipworm Egg

26. Whipworms

27. Medications for Whipworms
febantel , pyrantel pamoate and praziquantel
Drontal
fenbendazole
Panacur®
To achieve control, treatment can be administered once a month for 3 months.
Milbemycin oxime (found in: interceptor, triflexis, sentinel)

29. Tuesday March 24, 2015 Name these three parasites… A._____________
B. ____________
C. ____________
Name these three parasites…

31. Nematodes - Heartworms
Dirofilaria immitis
Parasite of the circulatory system
In dogs: right ventricle of heart and pulmonary arteries
Dog is definitive host

32. Heartworm Adult is called dirofilaria immitis
Larvae are called microfilaria
Found in the bloodstream
Migrate to the heart and lungs
Intermediate host is mosquito

33. Heartworm Heartworm disease in dogs HARD in cats
Heartworm associated respiratory disease
Medication:
Preventative - Ivermectin
Treatment – melarsomine
(Immiticide)

34. Cestodes Tapeworm spp Flea is intermediary host
Dipyldium caninum
Taenia taeniaeformis
Flea is intermediary host
Rodents, rabbits, deer = different species of tapeworms
Primary host (canine or feline) ingest the intermediary host
Eggs
Thin shelled, when found under microscope may find “packets”
Proglottids (tapeworm body segments) are filled with thousands of egg packets

35. Taenia or dipylidium

36. Tapeworms

37. Medication for tapeworms
Praziquantel (Droncit)
Epsiprantel, and
Fenbendazole
Preventative flea control!

38. Protozoa Single celled organism Giardhia Coccidia
(have a nucleus so are eukaryotic)
Giardhia
dogs, cats, humans, beavers
Coccidia
Isospora
Cryptosporidium
Toxoplasma gondii (cat is definitive host)

39. Giardia Live in the intestines From contaminated items or environment
Villi become damaged/ malabsoption occurs
From contaminated items or environment
Treated with metronidazole
Prevention
Cleanliness
Water, ground surface, soil, undercooked foods
Often fecal- oral transmission

40. Giardia - two forms Trophozites Feeding stage
Found in the small intestine

41. Oocysts Thick walled spore that protects
Cyst is ingested, wall is digested away, trophozite is released and immediate divides into two organisms
Binary fusion

42. Coccidia Isospora Oocysts in the feces
Sporulates (divide/ become infective)
2 sporocysts
Each enclose four sporozoites
Total of 8 infective forms per oocyst
Walls are digested and sporozoites penetrate intestinal cells
Grow, replicate, mature, “reproduce”
After fertilization, oocyst is produced and cycle starts over
Causes diarrhea
Affects very young and immune compromised animals
If severe infestation can mimic parvovirus and even be fatal

43. Toxoplasma and Cryptosporidium
Intestinal
Same type of life cycle as Isospora
Toxoplasma causes birth defects in humans
Cryptosporidium causes severe diarrhea

44. Isospora

45. isospora
Toxoplasma Gondii
cryptosporidium

46. Name the three parasites…

47. Roundworm and hookworm eggs

48. Answer
whipworm
Ascarid
(roundworm)

49. Ectoparasites
Fleas
Ticks
Mites

50. Flea Ctenocephalides felis Not host specific 65 - 80 ° Warm, humid
Cat flea
Not host specific °
Warm, humid

51. Fleas…a vicious (life) cycle

52. Flea lifecycle stages:
Egg - The flea egg hatches in 2-21 days, depending on environmental conditions.
Three larval stages - The larval stages grow and undergo their moults over about 9-15 days.
The pupal stage (cocoon) - The cocoon is the crux of flea infestation persistence in the house-hold. It generally hatches in 1-2 weeks, but can last up to a year.
The adult flea - Adult fleas can live for some weeks (maximum of about 2 months if no host is present) in ideal conditions.

53. Flea disease Anemia Tapeworms Plague Catscratch fever
(Yersinia pestis)
Catscratch fever
(Bartonella henselae infection)

54. Ticks – multiple host cycle

55. Tick life stages

56. Common species of ticks
Two families of ticks –soft ticks and hard ticks
Ixodid family (hard ticks)
Brown dog tick
Lone star tick
Deer tick
Diseases
babesia, ehrlichia, rocky mountain spotted tick fever, lyme, tularemia, anaplasmosis

57. Brown dog tick

58. Tick and Fleas medications are aimed at killing different stages of the parasites
Eggs
Larvae
Pupae (cocoons – fleas)
Nymphs
Adults

59. Neurotoxins Fipronil (Frontline) Imidaclopride (Advantix)
Permethrin (common brands)
Only kill adults
Other ingredients work synergistically as IGRs (Insect Growth Regulators)
Repellants
Amitraz (for ticks)
Cats- Use caution!!!

60. Mites Sarcoptic mites Sarcoptes scabiei Burrow into the epidermis
Pruritic skin condition
Rash
Scaling, crusting, excoriation
4 stage life cycle spent on the host
Eggs
Larvae
Nymph
Adult (takes days to become adult)
Contagious by direct contact
Zoonotic but self limiting in people

61. Sarcoptic mange

62. Ear Mites Otodectes cynotis Reside within external ear canal
5 stage lifecycle lived on host
Egg, larva, protonymph, deutonymph, adult
Common cause of otitis externa in dogs, cats, ferrets
Feed on dead cells on the ear canal / produce intense irritation
Head shaking/ scratching ears
Aural hematomas
Sometimes can be seen with otoscope
Prepared slide
Brown exudate usually will have mites moving around

63. Ear mites

64. Demodex Demodex Mites Live in hair follicles and sebaceous glands
Normal and nonpathogenic
Host specific / not transmissible
An increase of these mites is called demodicosis
Immune system related
May be localized to one area or generalized / all over

65. Demodex under the microscope

66. Cheyletiella Live on surface of skin – ingesting skin “debris”
Host is dog, cat, rabbit
“Walking dandruff”
Diagnostics
View moving “flakes” through magnifying glass
Cellophane tape
Flea comb
Area: dorsal midline and head

67. Cheyletiella

68. Ringworm Not a “worm” Is a fungus Zoonotic Keratin seeking
Dermatophyte
Lesions are circular