1. Endoparasites – Ruminants

2. Goals and Objectives Understand the influence of parasitism on
production
Become familiar with the types of parasites
afflicting agricultural animals
Understand the public health implications of
selected parasites
Understand the basic principles of parasite
control and treatment

3. Parasitology - Ruminants
Economic Losses
– Poor ADG
– Abortion
– Decreased conception rates
– Death
Public Health
– Zoonoses

4. Reasons For Economic Losses
-Producer Unaware of parasite damage
estimate annual parasite-related losses to the livestock industry at more than $100 million
- Timing & Frequency of treatments
-Choice of dewormer
-Parasites have greatest impact on high producing animals.

5. What is ruminants Parasitism?
It is a herd disease
It is a production disease
It develops during grazing
99% of all pastures contaminated

6. Level of Parasitism Related To
Age of animals
Pasture contamination level
Stocking rate of animals
Grazing environment & Weather
Immune status of animals

7. Deworming strategy -Producers understand importance of
internal parasite control for production
efficiency.
-Deworming is now standard practice on beef
and dairy farms.
-Must have correct product at the correct
time.

9. Definition Types of relationships between organism and host
– Commensal ‐ one benefits without harming the
other
– Mutualism ‐ both participants benefit
– Parasitism ‐ one benefits at the expense of the

10. Definition Endoparasite ‐ internal infection
Ectoparasite ‐ external infestation
Zoonotic infection ‐ transmission of an infection from animals to humans

11. Definition
Life cycle ‐ from the start of one generation to the start of the next
– Direct ‐ completion of life cycle requires a single host
– Indirect ‐ completion of life cycle requires greater than one host

12. Direct Lifecycle

13. Indirect Lifecycle

14. Definition Definitive Host ‐ where sexual reproduction of
parasite occurs
Intermediate Host ‐ required to complete a
developmental phase in the parasites life‐cycle,
excluding sexual reproduction
Pre‐patent Period ‐ time from infection of definitive host to the production of parasite offspring

15. Designing a Program in a Dairy/Meat Operation
First determine the approximate level of parasitic contamination

16. 1.- High Parasite Contamination Level
Cows grazing pasture during lactation
When rotational grazing is practiced

17. 2. Moderate Parasite Contamination Level
Cows grazing pasture only during dry period
Cows with access to an exercise lot only (with some grass)

18. Low Parasite Contamination Level
Cows with access to dirt dry lot

19. 4. Extremely Low Parasite Contamination Level
Cows in total confinement
Cows on a concrete dry lot

20. Summary Strategy For Lactating Cows
Parasites have been shown to decrease milk production in early lactation
Identify parasite contamination levels in each dairy operation
Design deworming program based on individuals or herd treatment relative to contamination levels

21. Parasite – Indications
Purpose of the tests
Direct-aids in the detection of certain protozoan trophozoites.
Flotation method-eggs in feces are mixed with flotation solution that will cause them to float to the top.
Baerman Funnel Technique-larva migrate to the bottom. Used to detect lungworms in ruminants.
Centrifugation technique-will detect parasitic eggs when other techniques do not, specially heavier eggs that will not float.
MIF (merthiolate iodine formalin) –satins and preserves protozoans & larvae

22. Modified Wisconsin Sugar Flotation Method
Technique
Samples can be stored if refrigerated
Sugar solution
– One pound of sugar.
– Add to 12 oz(355cc) of hot water.
Slides can be refrigerated for reading later
Materials
Sugar solution & dispensing syringe
Tea strainer
3/5 oz dixie cups
Tongue depressors
Taper bottom 15cc tubes
Test tube rack
Microscope slides & 22x22 mm cover slips 22

23. Modified Wisconsin Sugar Flotation Method
Add cc sugar
solution to sample 23

24. Modified Wisconsin Sugar Flotation Method
Place grams of
fecal material into a 3
oz paper cup
(About a thimble full) 24

25. Modified Wisconsin Sugar Flotation Method
Stir solution & fecal
sample to an even
consistency. 25

26. Modified Wisconsin Sugar Flotation Method
Stir solution & fecal
sample to an even
consistency. 26

27. Modified Wisconsin Sugar Flotation Method
Use a tongue depressor,
press as much material
through strainer as
possible. 27

28. Modified Wisconsin Sugar Flotation Method
1. Pour into 15cc taper
bottom centrifuge tube.
2. Centrifuge in swinging arm centrifuge at 900
rpm for 5 – 7 minutes. 28

29. Modified Wisconsin Sugar Flotation Method
1. Place tube in rack and top off with sugar solution to form a meniscus.
2. Place 22x22 mm
cover slip on tube
and leave in place
for minutes. 29

30. Modified Wisconsin Sugar Flotation Method
Lift cover slip upward
& place on slide 30

31. Modified Wisconsin Sugar Flotation Method
Use microscope to
scan entire cover slip
for egg count 31

32. 32

36. Definition Types of parasites
– Nematodes (phylum nemathelminthes)‐ round worms
– Cestodes (phylum platyhelminthes) ‐ flat worms
– Trematodes (phylum platyhelminthes) ‐ flukes
– Protozoa (phylum protozoa) ‐ single‐celled eukaryotes

37. Nematodes Adult worms – male and female
– range in size from large to microscopic
• Eggs →Larvae (stage 1‐4) →Adult
– Most have direct life cycles
– Most transmitted as infective larvae on pasture
• GI tract and lungs as adults

38. GI Nematodes • ~ 11 Genera, Many Species • Sites
– abomasum, small intestine, cecum, and large
intestine
• Most ruminants = chronic infections
• Production losses and clinical disease are
proportional to severity of infection

39. GI Nematodes – Hot complex
• Haemonchus contortus
– 1” (25 mm)
– Abomasum of small ruminants
– feeds on blood
– Clinical signs
• anemia
• death

40. Clinical signs Haemonchus
Calf is in poor condition with ‘bottle jaw’ due to hypoproteinemia and anemia.
It is massive direct damage, usually late winter.

41. Adults in the abomasum.
Barberpole worm

42. GI Nematodes Ostertagia ostertagi – 1/2” (10 mm) adult worm; abomasum
– most serious impact on calves
– disrupt gastric acid secretion
– Clinical signs
• diarrhea
• ill‐thrift
• poor feed conversion

43. Ostertagia ostertagi

44. GI Nematodes Trichostrongylus axei – “Bankrupt worm”
– Adults ~1/4” (4‐8 mm); abomasum
– Clinical signs
Diarrhea
dehydration
bottle jaw
emaciation

45. Platyhelminthes (flatworms)
• Hermaphroditic
• Intermediate host (indirect life cycle)
• Flattened appearance
• Tapeworms (Cestodes)
• Flukes (Trematodes)

46. Tapeworms (cestodes) Adult worms few inches to 15 yards long
• Segmented worms with attached head
(scolex)
• Ruminants = intermediate host for canids and
humans
• Ruminants eat eggs passed in feces of canids
or people

47. Tapeworms (cestodes) Cysts in carcass, pea‐size to grape‐size (beef
measles)
• People/canids infected by eating encysted
beef
• Carcass condemnation
• ID, WA feedlots ‐ cattle infected with beef
tapeworm of man (Taenia saginata); 10% losses in some feedlots

48. Taenia saginata

49. Liver Flukes (Trematodes)
Fasciola hepatica (most common); Fascioloides
magna
– Live in bile ducts as adults
– Aquatic snails = intermediate host
– Clinical signs
• photosensitization
• reduced ADG
• hepatitis; clostridial dz →death
– Condemned liver at slaughter
• $millions in losses

51. Protozoa Single‐celled eukaryotes • Amoeba; Ciliates (not discussed)
• Apicomplexa
– Eimeria, Cryptosporium, Toxoplasma, Neospora
• Flagellates
– Tritrichomonas, Giardia

52. Apicomplexa Intracellular protozoa • Coccidia
– Sexual reproduction in intestine → oocysts in feces → definitive (direct) host or intermediate (indirect) host

53. Eimeria Direct life‐cycle (all ruminants)
• Invade intestinal epithelium
– destruction of epithelial cells
– disruption of intestinal function
• Clinical signs
– acute and chronic disease
– watery and/or bloody diarrhea
– decreased ADG → clinical disease → death
– young >> adult

54. Cryptosporidium parvum
Apicomplexa
• Similar to Eimeria
• Clinical signs
– diarrhea 1‐2 week old calves
– disease severity varies
• Zoonotic: – particularly with immunocompromised host

55. Toxoplasma gondii Indirect life‐cycle • Cat = definitive host
– oocysts shed in cat feces
• Ruminants = intermediate host
– tissue cysts
• Transmission to developing foetus
– abortion
• Zoonotic

56. Neospora caninum Indirect life‐cycle • Dog = intermediate host
• Clinical signs
– abortion
– neurologic disease in calves born alive

57. Flagellates Mastigophora (flagellates that move with a whip)
• Extracellular parasites
• One or more flagella ‐ assist with movement
• Divide by binary fission
• Example
– Tritrichomonas foetus

58. Tritrichomonas foetus
Simple reproduction
– binary fission
– trophozoite is only stage
• Venereal disease of cattle (bull = carrier)
• Clinical signs
– early abortion
– pyometra
– significant $losses due to decreased preg. rate

59. References
Large animal clinical procedures for veterinary technicians, Elizabeth A. Hanie, 2006