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Flashcards in Farm animal diarrhoea Deck (53)
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1
Q

Is diarrhoea a serious condition in young calves

A

Yes can be fatal

2
Q

What are the 3 factors involved in diarrhoea in farm animals?

A
  1. pathogens
  2. calf factors (immune system, stress - dystocia etc)
  3. environment and management
3
Q

What causes other than pathogens should always be considered when looking at LA diarrhoea?

A

Dietary problems

4
Q

Give 6 pathogens that may cause calf diarrhoea

A
  1. E. Coli
  2. Rotavirus
  3. Coronavirus
  4. Cryptosporidium
  5. Salmonella
  6. Coccidiosis
    > mixed infections common
5
Q

What is E. COli infection in lambs often called?

A

Watery mouth

6
Q

Is diarrhoea always present in an infected calf?

A

NO - find out why!?

7
Q

Why can E. Coli cultures not show definitive Dx?

A

All feaces will grow E. Coli when cultured (normal inhabitant of the colon)

8
Q

When can E. Coli cause problems?

A
  • Extra intestinalinfectin (colisepticaemia)
  • enteric disease from special strains (ETEC)
  • public health: special strains (STEC)
9
Q

What is watery diarrhoea referred to as?

A

Scours

10
Q

What causes scours?

A

Enterotoxigenic E. Coli (ETEC)
Small intestine E Coli numbers increase from 10^4 -> 10^9/ml
- Coupled with management / lack of colostrum

11
Q

Does the pathogenesis of scours differ in different animals?

A

No

12
Q

What age does neonatal enteritis due to ETEC occour?

A

1 - 3 weeks, younger = more common

13
Q

Are the serotypes of E. Coli relevant to their pathogenicity?

A

No - there is an association but no correlation/causation

14
Q

What is the pathogenesis of ETEC?

A
  • ingestion
  • colonisation of lower SI
    > other agents
  • D+
  • stunting of villi
15
Q

What other pathogen is often seen in conjunction with ETEC?

A

Rotavirus - diseases excacerbate each other

16
Q

What 2 factors does ETEC require to become pathogenic? Where are these encoded?

A
  • adhesive fimbriae (colonisation factor)
  • enterotoxin
    > encoded on plasmids (may be both on the same plasmid)
17
Q

How are adhesive fimbriae/colonisation factors referred to on drug packets?

A

K= old style
F=more modern terminolgoy (fimbrial)
K88 (pigs) F4
K99 (pig, cow) F5

18
Q

Which colobnisation factors are responsible for “travellers diarrhoea”?

A

CFA1, CFAII

- zoonotic

19
Q

What are the two types of enterotoxin? What are their actions? Can they be protected against?

A

> LT - labile toxin
- Ab in colostrum so vax possible
- similar to cholera toxin - attaches to brush border of SI cells
- causes Cl- channel activation -> secretion of Cl-, Na+ and water from tissues -> active secretion
-> metabolic acidosis, dehydration, electrolyte loss, can be fatal.
ST stable toxin
- mechanism less well understoof
- too small to trigger immune response

20
Q

How is diagnosis of ETEC decided?

A
  • clinical grounds
  • culturing feaces will always yiled E. Coli (indistinguishable from pathogenic strains)
  • to demonstrate ETEC must show
    > LT Toxin or gene
    > K88 fimbriae or gene
    in the same organism!
  • Takes time and money.
21
Q

What does STEC stand for? What was in previously known as?

A

Shigga-toxin producing E Coli

- previously EHEC (enterohaemorrhagic E coli)

22
Q

What does STEC cause?

A

Some diarrhoea and haemorrhagic colitis in calves
-> contaminated beef can infect humans and -> haemorrhagic colitis and healolytic uraemic syndrome -> renal failure in humans

23
Q

What age does rotavirus affect calves?

A

1-3 weeks

24
Q

Where does rotavirus affect? Morbidity mortality?

A
  • duodenum and jejunum

- ^ morbidity v mortality

25
Q

How is rotavirus spread and which animals is it commonly seen in?

A
  • Shed by cows and older calves, persists in environment

- Esp seen in beef where adults and calves kept at pasture together

26
Q

What age does coronavirus affect calves?

A

1 - 4 weeks, usually slightly older

27
Q

Where does coronavirus affect? Morbidity mortality?

A
  • ileum, ceacum and colon

- slightly higher mortality than rotavirus due to LI involvement

28
Q

How is coronavirus spread?

A

Shed by cows and older calves, persists in environment - cohabiting with rotavirus?

29
Q

Give a reportable zoonotic public health risk infection of cattle. How is this treated?

A

Salmonella - culture of salmonella is ALWAYS significant.

Treated with antibiotics

30
Q

What age animal is affected by salmonella? What are the clinical signs associated with infecton?

A
  • any age of animal

- systemic illness and pyrexia

31
Q

Who do reportable disease have to be reported to? What are the next steps following reporting?

A

VLA (Vterianry laboritoris agency) now AHVLA (Animal health vet lab authority)

32
Q

What age are clinical signs of cryptosporidium seen? What is the PPP of crypto?

A
  • clinical signs 5-14 days, PPP 2-7d
33
Q

Where does cryptosporidium affect? Pathogenesis? Clinical signs?

A
  • lower SI/colon
  • villous atrophy -> malabsorption
  • often concurrent disease
  • RESISTANCE develops with age
    > white pasty diarrhoea
    > immunosuppression -> 2* infections
34
Q

Can cryptosporidium persist in the environment?

A

Yes

35
Q

What age does coccidiosis affect calves?

A

> 3 weeks

weaned calves

36
Q

What are the clinical signs associated with coccidiosis?

A

Heamatochezia, tenesmus

Subclinical -> poor growth rate, 2* infections due to immunocompromise

37
Q

How can coccidiosis be diagnosed? What must be remembered?

A

NB: pathogens can be present in the absence of clinical signs

  • take faecal sample (not swab)
  • sample healthy AND affected animals (as many as possible)
  • bacteriology, virus isolation and typing necessary at lab
38
Q

Is faecal appearance a good indicator of the type of disease?

A

NO

39
Q

List 6 pathogens able to cause diarrhoea in cattle and the age they are likely to occour.

A
  • E Coli: < 5d
  • Cryptosporidium parvum: 5-14d
  • Rotavirus: 1-2weeks
  • Coronavirus: 1-3 weeks
  • Coccidiosis: >3 weeks
  • Salmonella: all ages
40
Q

Give 4 calf factors that may influence development of diarrhoea

A
  1. accessibility to colostrum
  2. dystocia -> stress, weakness, v feeding, ^ time on ground
  3. competition
  4. cow factors - quality of colostrum, allowing calf to suck?
41
Q

How does colostrum affect mortality rates?

A

Calves with inadequate colostral status = 4x more likely to die than those with good status

42
Q

Give examples of good and bad husbandry and management practice related to calf diarrhoea

A

Good:
- buckets outside pens - prevents faecal contamination and knocking over
- water - otherwise will drink milk for thirst -> rumen cause problems
- spaced pens (but lack of social contact bad)
- clean calving pen
Bad:
- deep litter
- starving calves to encourage earlier weaning onto solids (lowers immunity)
- feeding insufficient CMR (calf milk replacer) - should be fed 15-20% body weight per day in volume

43
Q

What are the 3 main reasons for diarrhoea in he growing/adolescent cow? Give egs.

A
> endoparasites 
- ostertagia
- coccidian
- fluke
> Nutiritonal
- rumen acidosis
- cu deficiency 
> Infectious 
- salmonella 
- mucosal disease (BVD PI) - non cytopathic mutates to cytopathic, 6-18months
44
Q

What other symptoms would be seen with Cu deficiency?

A

Coat changes - spectacled appearance

45
Q

What are the 3 main reasons for diarrhoea in the adult cow? Give egs.

A
> endoparasites 
- fluke
-ostertagiosis
> nutritional 
- SARA
> infectious 
- Johnes disease (MAP)
- Salmonella
- Coronavirus (winter dysentery - transient 4-5d scour)
46
Q

What pathogen causes Johnes disease?

A

Mycobacterium avium subspecies patratuberculosis

47
Q

What are the clinical signs of Johnes? What route is infection by?

A
  • severe D+
  • weight loss
  • dull
  • off milk
  • faecal-oral route, all cows infectious escpecially feaces
48
Q

What is the treatment for Johnes?

A

None - must be culled on humane grounds

49
Q

Is Johnes zoonotic?

A

Potentially - may be involved in Chron’s IBD in humans

50
Q

WHen is Johnes disease acquired?

A

Youngstock - but remains subclinical until at least 2 years later.

51
Q

How can Johnes be controlled?

A

Prevent neonates becoming infected from feaces older animals/colostrum
- avoid pooled colostrum
- test before buying in
- don’t spread slurry
BUT can be infected in utero
Breed to beef so that culled offspring are economically useful

52
Q

How can subclinical Johnes be detected?

A

Can’t very easily - issues with lab tests

53
Q

How is Johnes diagnosed? What is the accuracy of these tests? What is the gold standard diagnostic test?

A

> ZN smear (cheap)
ELISA blood test has low sensitivity but high specificity - ie. + is + but - is NOT necessarily - (cheap)
milk test also available
faecal PCR slightly more specific
Individual feacal culture = Gold standard (expensive)
test is more sensitive in clinically infected cows than subclinical
necroscopy PM