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Single Agent Infectious Diseases Flashcards

1
Q

Infection with bovine herpes can turn into what disease?

A

Infectious bovine rhinotracheitis (IBR)

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2
Q

CS of BoHV infection?

A 
Pyrexia
Dull
Decreased appetite
Fluid discharge from eyes / nose
Sudden decrease in milk production
Pharyngitis
rapid, loud breathing, +/- cough

+/- abortion, embryo death, neurosigns in neonates

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3
Q

Dx of BoHV infection?

acutely sick vs herd

A

Acutely sick animals get direct tests = Best is ocular conjunctival swab
(send that off for PCR, virus isolation, or FAT)
[nasopharyngeal swab and semen used less often]

Herd = serological Ab testing; bulk milk tank test very useful

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4
Q

Tx of BoHV infection?

A 
NSAIDs
Rest and nursing
Remove from stress
Abx if worried about 2ndry infection
Vaccination of the rest of the herd
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5
Q

Which single agent infectious diseases have vaccinations?

A

BoHV, BVD, Lepto, Salmonellosis,

Johnes can get to import (interferes with TB testing)
Neospora in some countries ( low efficacy)

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6
Q

What types of vaccination are available for BoHV?

And what are they licensed to do?

A

1) Conventional
2) Marker [no glycoprotein E, so no Ab to E - can tell the dif. b/w infection and vaccine]
3) Live-attenuated
4) Killed (inactivated)

Licensed for decreasing amt of shedding during primary infection and reactivation, and decrease severity of clinical signs.

Vaccines DO NOT prevent latent infections or reactivation!

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7
Q

What kind of virus is BoHv and what are the common subtypes?

A 
alpha virus
subtypes =
1.1 (IBR + abortion)
1.2a (reproductive, IPV/IPB, abortion)
1.2b (reproductive, IPV/IPB, NOT a cause of abortion)
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8
Q

What is the pathogenesis of BoHV?

A

Naive animal -> infection-> (shedding) -> latent infection -> stress -> reactivation and secondary infection -> shedding

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9
Q

How is BoHV shed and spread?

A

Spread by direct contact (mostly)
Respiratory secretions (contact & aerosol, 3-5m)
Venereal (semen, fluids)
+/- indirect spread (fluid on clothing)

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10
Q

what happens to virus during latent infection of BoHV, and what about Ab?

A

Virus is latent in nerve ganglion and has potential to reactivate at any point in life

Ab titer persists! (for both E an B glycoproteins)

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11
Q

What happens during reactivation? What can cause reactivation?

A 
CS rare (b/c Ab to fight it), VIRUS SHEDS!
Stress can cause this, immunosuppression (high dose dex), Lameness, disease, nutritional stress
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12
Q

Describe/draw Ab levels @ MDA, primary infection, latent, and reactivation

A

See notes

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13
Q

In what situations will you get a latent infection w/o any circulating Ab?

A

Seronegative latent carrier

= infections when maternal antibodies present

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14
Q

If you do a glycoprotein E ELISA on a uninfected cow with a marker vaccine, what will teh result be? [for BoHV]

A

Negative

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15
Q

If you do a glycoprotein B ELISA on an uninfected cow with a conventional vaccine, what will the result be? [for BoHV]

A

Positive

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16
Q

If you do a glycoprotein B ELISA on an uninfected cow with a marker vaccine, what will the result be? [for BoHV]

A

Positive

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17
Q

What are the 3 main steps to monitoring herd control of IBR?

A

1) set a clear goal
[ex- for non-infected herds, your goal = remain free / for infected but low prevalence, your goal = eliminate from herd / for high prevalence, your goal = prevent spread]

2) coordinate essential components
[bioexclusion, cull/isolate latent infections, regular herd vaccination]

3) monitor progress
[repeat investigative herd testing @ regular intervals]

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18
Q

What are the 3 main questions to ask when setting your goals for herd control of IBR? and how would you investigate them?

A

1) Is the herd infected? = Hx, bulk tank Ab test
2) How many are infected? = sample proportion to determine prevalence
3) Which ones are infected? = Individual screen tests

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19
Q

What kind of virus causes BVD?

A

Pestivirus (RNA)

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20
Q

What are the 2 biotypes of BVD?

A

Cytopathic (CP)

Non-cytopathic (NCP)

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21
Q

What impact does an initial infection with BVD have on herds?

A 
Decreased fertility
Abortion
Congenital defects
Stunted calves
Immunosuppression
Transient diarrhea in adult naive herds
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22
Q

What is required for a BVD infected cow to get Mucosal disease?

A

The cow must be infected with NCP strain and then Ag-related CP virus

mechanisms = mutation of the NCP strain in PI animal, or superinfection of PI animal by CP virus

ONLY PI ANIMALS GET MUCOSAL DISEASE!

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23
Q

What are the classic signs in calves of an in-utero infection?

A

wide based stance, nystagmus, shaking as it puts his head down

cerebellar hyperplasia!

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24
Q

How does a PI cow get Mucosal disease?

A

Mucosal disease arises when an immunotolerant PI cow w/ NCP strain already, becomes superinfected with CP strain of same antigen (NCP strain mutation or from env)

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25
What age is Mucosal disease commonly seen?
6 mos - 2 years
26
What is the consequence of mucosal disease
Death
27
What happens when infected w/ BVD during pregnancy at day 0? (non-immune)
Ag + / Ab - (PI CALF!) | PI calf, or early embryonic death, abortion, or fetal stunting
28
What happens to fetus when infected w/ BVD during middle 3rd of pregnancy? (non-immune cow)
Congenital defects, abortion, fetal stunting | after fetal immune system development
29
What happens when infected w/ BVD during last 3rd of pregnancy? (non-immune cow)
Ag - / Ab + | Abortion or fetal stunting
30
If an immune cow is infected w/ BVD during pregnancy what will happen to the fetus?
nothing | Will still create Ab in colostrum
31
What are the CS or Mucosal disease?
``` Depression, decreased appetite Salivation Diarrhea (profuse, watery, foul smelling) Lacrimation +/- crusting around nose Decrease BCS ``` ``` Ulcers - all oropharynx & onto muzzle Dry, cracked, inflammed rhinarium Oral pain Oral flare/flush - redding of MM Ulcers in interdigital cleft +/- dermatitis - scabs/skin crusts Foul smelling ulcers ```
32
Dx of Mucosal disease? (ind. vs herd)
``` Individual = CS (should be enough) Serology for PI (PI = Ab -, Ag +) Virus isolation PM ``` ``` Herd = Bulk milk testing* Ind. animal blood samples EAR NOTCH SAMPLES Test bulls & herd replacements (test animals coming in) ```
33
What do you do if you find a PI cow?
Cull
34
Tx for BVD?
rapid recovery in a few days
35
When ear tag samples come back Ag +, what can this mean?
PI or Transient infection
36
If an ear tag sample comes back positive, what do you do?
confirmatory testing 3-4 weeks later (to see if transient infection)
37
What test can detect infected calves in the face of maternal-derived Ab?
RT-PCR
38
What causes Johne's?
Mycobacterium avium paratuberculosis
39
How do cattle get injected with Johne's?
Oral (feco-oral) Transplacental Via milk or colostrum
40
CS in beef vs. dairy for Johne's?
Both have = poor BCS, Decreased fertility Usually remain bright until terminal stages Dairy = Decreased milk yield, Increased ICSCC, usually culled for poor performance Beef = Small calves, Calf ill-thrift, Diarrhea (homogenous, watery, no blood), Peripheral edema (submandibular - bottle jaw)
41
Dx of Johne's
Hx, CS Diagnostic Tests = Ab - serum and milk ELISA (most common) fecal PCR, smear, culture PM & histopath ELISA testing = 50% sensitivity, can get many false negatives, 99% specificity, beware after TB TESTING (false positives)
42
What do you have to be wary of with false positives for Johne's ELISA?
TB Testing can lead to false positives
43
What do the colors on a Milk ELISA hx mean? | (blue, red, green, yellow) [Johnes]
``` Green = low risk (negative quarterly milk testing) Yellow = 1 + quarterly sample (but take another, b/c possible false +) Blue = born of high risk cow Red = high risk, probably cull ```
44
What is normal screening for Johne's?
``` ELISA based Blood test all animal > 2 years old annually Milk ELISA test quarterly Cull any + Manage + as leper colony (keep separate) ```
45
How does a farm become "Johnes accredited free"?
Get 3x annual clear tests
46
When is PCR testing useful? [Johne's]
In areas of high TB testing | more sensitive, picks up cases that you would miss w/ blood testing
47
What are 5 main steps to Johne's control in beef herds?
1) ID status of breeding cattle 2) Separate into negative and positive groups 3) Biosecurity 4) keep replacements from negative cows 5) Slurry and/or manure management - not on pasture grazed by youngstock, esp. slurry from known positives
48
Tx of Johne's?
NONE! | get + cows off farm ASAP
49
How is Johne's spread on the farm?
Feces, Milk, Transplacental | shared water sources, if a + cow shits in water
50
What management things must be done to control Johnes?
Test & cull Calf rearing, cleanliness, colostrum, replacement milk, pasture/slurry Vaccination (import, interferes w/ TB testing)
51
Johne's control in dairy herds?
Same as beef, and don't pool colostrum in herds w/ known Johne's dz w/ cows w/ unknown/+ tests Aim = individual calving area, remove calves @ birth, then feed colostrum separately (of calves from + cows)
52
What's up with the Johne's vaccination?
Import only Needs approval Interfere's with TB testing!!
53
Public health concerns for Leptospirosis?
Zoonotic!
54
CS of leptospirosis?
Primary infection = NO clinical signs Pyrexia (41C) 2 syndromes: 1) milk drop syndrome 2) sudden fever / agalactia All quarters soft & flabby & yellow sections Abortion (or infertility): delayed 6-12 week post infection once infection isolated to kidneys and uterus. Tends to affect younger cattle more frequently
55
Dx of Lepto?
Bulk milk Ab Blood Ab (serology) [serial testing, 2 samples a few weeks apart] Urine: culture difficult, PCR to look for genetic material, dark brown microscopy or FAT to directly visualize Rapid spike in IgM/G in blood detected by ELISA; rapid peak declines over several weeks still with seropositives Renal carriage: extended period of shedding >18 months Detection of Ab after abortion is NOT DIAGNOSTIC!
56
Tx of Lepto?
High dose Streptomycin - decreases renal carriage (ex- pen & strep) NSAIDs: flunixin, as pyrexic Fluid therapy: if stopped eating & drinking, and are dehydrated
57
Vx for Lepto? what are its indications?
2 licensed vaccines: to reduce renal carriage and shedding, one has claimed to improve fertility 1) Leptavoid -H 2) Spirovac
58
How is lepto shed? transmitted?
Urine mainly through water sources semen Infection through abrasions, MM (so urine splashing is a risk factor)
59
Control of Lepto?
``` Herd control = isolation muck out straw pen bull check (semen sample?) High dose strep - reduce shedding Be aware of zoontic risk when milking or handling new abortions! ```
60
CS of Neospora caninum infections?
Often NO CS Abortion is the ONLY CS (may rarely see weak born/neuro calves from infected calves)
61
What are IMH and FH for Neospora?
``` IMH = Cows FH = Dogs ``` Localize to brain / CNS and muscles as bradyzoites in cattle
62
Dx of Neospora caninum infection?
PCR of brain of the aborted fetus Check the dog; definitive host tricky Placenta? (prefer fetus) Limited use for Ab - after abortion Animals become lifelong carriers and higher risk for abortions (98% offspring infected too) - Ab are produced w/ fluctuating titer
63
Tx for neospora caninum?
NONE cows are not sick (unless RFM, then sick) Put animal down via gun or euthatal
64
spread of neospora caninum?
98% vertical transmission Horizontal transmission = Oocysts in dog feces No direct spread cow to cow
65
Herd control for neospora caninum?
Cull carriers = what if high prevalence? Deal with horizontal spread - stop dog eating placenta Deal with vertical spread - ET (need negative recipients), purchase negative replacements? breed to beef Public footpaths - info signs regarding dogs spreading disease
66
What causes malignant catarrhal fever?
Ovine herpesvirus -2 | Alcaphine herpesvirus-1
67
CS for MCF?
``` Extensive VASCULITIS Severely sick animal Pyrexic Lymphadenopathy Anorexia copious mucopurulent oculo-nasal discharge +/- blood Drooling saliva Congested sclera vessels Corneal edema hypopyon (inflammed cells in anterior chamber - irisitis) Diffuse oral/nasal ulceration ```
68
Dx of MCF?
Ab in serum or from affected tissues PCR for AHV in blood or tissue (ex- conjunctival swab) PM - linear ulceration of esophagus [DDx MD]
69
DDx for MCF?
Mucosal disease | Foot and mouth Disease
70
Tx of MCF?
``` normally fatal (if you see CS) Some do survive ``` Euthanasia! Otherwise supportive therapy; but (almost) always fatal
71
Control for MCF?
Avoid contact w/ sheep @ lambing time (b/c of ovine herpesvirus 2)
72
What causes Listeriosis?
Listeria monocytogenes
73
pathogenesis for Listeriosis?
Invasion through gumline into CN -> septicemia
74
CS for Listeriosis?
CN deficits: circling, head tilt (vestibular), unilateral facial paralysis (ear droop, drooling, off feed) ``` Less common: Abortion (more common in sheep) Neonatal septicemia (think colostrum!) Spinal abscesses Mastitis ```
75
Dx of Listeriosis?
Organism is ubiquitous, therefore so are the Ab! (CAN'T USE SEROLOGY!) CS Brain from animal affected, or aborted material & isolation of L. monocytogenes Lumbosacral CSF tap: increase protein, mild pleocytosis (increased cell count) Immunofluorescence
76
Tx of Listeriosis
Abx!! [Oxytet, Amoxi] NSAIDs Nursing Fluid therapy Recovery usually depends on how much residual damage done, can recover quickly once tx initiated
77
Control of Listeriosis
Found in feces, soil, decaying herbage/silage - ubiquitous Care when making silage (avoid soil contamination) Stop feeding poor quality silage if clinical cases Ends and top soiled; STOP feeding to youngstock
78
What cause Salmonellosis?
Salmonella typhimurium / dublin
79
What parts of the body does salmonella most affect?
Intestines & bladder
80
CS of Salmonellosis?
CS may be absent Pyrexia Abortion Acute (painful) NECROTIZING HEMORRHAGIC ENTERITIS (fould smelling, bloody diarrhea) - unlike neospora Bruxism (teeth grinding) Osteomyelitis, dry, gangrene, enteritis, septicemia, meningitis, joint ill
81
Dx of Salmonellosis?
Ab response detectable by: SAT (serum agglutination test) Increasingly being replaced by ELISA -Detection of Ab after abortion IS NOT DIAGNOSTIC!! Confirm dx: Fetus to lab -> stomach contents culture the feces
82
Tx of Salmonellosis?
Fluids NSAIDs Abx - Trimethoprim Sulphonamide!, beta lactams, fluoroquinolones
83
Prevention of Salmonellosis?
Vaccination - Dublin and typhimurium in one vial | Creates Ab response (serum/colostrum)
84
Control of Salmonellosis?
Herd control = isolate the sick animal, vaccinate - target towards breeding seasons, etc. high periods of risk Reduce fecal contamination of feed Limit exposure to vermin/birds: control/proofing shed Other actions: biosecurity - buying in? isolation/quarantine - test Zoonosis - don't eat crap, clean and disinfect you / clothing before eating
85
Spread of Salmonellosis?
Shed in feces therefore mainly fecal-oral In feed, vet, slurry, rodents, birds S. dulbin = cattle is maintenance host S. typhimurium = less, sporadic cases - dose dependent

Cattle (2 decks)

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