Lecture 4: Swine Viruses 1 Flashcards

1
Q

What are the general clinical signs of porcine viral enteritis

A
  • General clinical signs: acute watery diarrhea, loss of appetite
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2
Q

What is the prognosis of porcine viral enteritis?

A
  • Prognosis: 60% mortality in suckling pigs, 2% mortality in feeder/grower
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3
Q

What should you expect on necropsy when looking at porcine viral enteritis

A
  • Necropsy; grossly: watery intestines, no significant lesions
    o Histo: observe the tropism (preference for different cells)
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4
Q

What are the possible agents causing porcine viral enteritis and what ages of pig does it affect?

A

o Rotavirus: suckling pigs and weaners

o Transmissible gastroenteritis virus (corona): All ages

o Porcine epidemic diarrhea virus (corona): All ages

o Delta coronavirus: All ages

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5
Q

What are the clinical signs of rotavirus induced porcine viral enteritis?

A

 Clinically: waves of diarrhea in 2nd half of lactation

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6
Q

What cells are affected by porcine rotavirus

A

 Histo: tropism for mature enterocytes

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7
Q

Clinical consequences of Transmissible gastroenteritis virus

A

 Clinically: vomit/acute watery diarrhea/weight loss/dehydration/agalactia
 More severe if young

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8
Q

What is a unique feature of Transmissible gastroenteritis virus

A

 Forms the respiratory porcine corona virus by a deletion of a 225 aa in spike protein

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9
Q

What is the morbidity and mortality of Porcine epidemic diarrhea virus

A

 Morbidity: can be 100%
 Mortality; 80-100% suckling piglets, if >10day = <10%, adult <5%

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10
Q

What are the clinical signs of Porcine epidemic diarrhea virus

A

diarrhea/vomiting/metabolic acidosis

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11
Q

What is the incubation period of Porcine epidemic diarrhea virus

A

 Incubation: 3-4 days

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12
Q

What are the features you would see on necropsy of Porcine epidemic diarrhea virus

A

 Histo: shortened villi (tropism for mature enterocytes)
 Gross: thin walled/watery intestines

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13
Q

How to diagnose Porcine epidemic diarrhea virus

A

 Dx: RT-PCR/ELISA/IHC to identify, and ELISA/immunofluorescence/serum neutralization for serology (ig response)
* Use feces/oral fluid/small intestine/serum

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14
Q

How to prevent Porcine epidemic diarrhea virus

A

 Prevent; natural maternal immunity (colostrum) until 4-13 days if mom immune/biosecurity/no vaccination in NA

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15
Q

What are the clinical signs of delta coronavirus

A

 Clinically: diarrhea/vomiting/metabolic acidosis

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16
Q

What are the features of porcine coronavirus causing viral enteritis?

A

o Corona virus: many litters with acute diarrhea and high mortality
 Highly infectious in piglets
 Similar lesions

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17
Q

What are the viral features of Porcine Parvovirus

A
  • Viral features: ssDNA, non-enveloped
    o Requires rapidly replicating cells (fetal cells have high mitotic index)
18
Q

How does porcine parvovirus appear clinically

A
  • Clinically: SMEDI (stillbirth, mummification, embryonic death, infertility)
    o Sows with no clinical signs
19
Q

How is porcine parvovirus transmitted

A
  • Transmission: body fluids/feces
    o Only transmitted to fetus in seronegative/naive animals
    o Epithelia-chorial placenta = many barriers
    o Probably transport via immune cells
20
Q

What is the pathogenesis of porcine parvovirus

A
  • Pathogenesis: transmission 12-18 day after initial infection of dams
    o Before day 35 = embryonic death
    o Day 35-70 = fetal death and mummification
    o >day 70 = survival/seropositive
21
Q

How does parvovirus affect other species (not pigs)

A

o Canine/Feline: affect crypt enterocytes
o Porcine: no enteritis/neuropathy – mainly a reproductive disease
o Bovine

22
Q

How to diagnose porcine parvovirus

A
  • Dx: females return to estrus, increased number of mummified/small litters
    o Submit to lab – use immunofluorescence to detect virus
23
Q

How to prevent porcine parvovirus

A
  • Prevent: killed vaccine
  1. Sow born (passive immunity provides protection for 3 weeks post birth)
  2. day 22 = inital vx
  3. day 28 = booster vx (1 wk later)
  4. day 32 = sow is bred/conception
    vaccine provides immunity for firrst 70 days of preganacy
24
Q

What causes Porcine Respiratory Disease Complex

A
  • Multifactorial
    o Viruses; pseudorabies/porcine respiratory and reproductive/swine influenza/porcine respiratory corona/porcine circo viruss
    o Bacteria
    o Other factors: stress/poor ventilation/over crowding
25
Q

What type of virus is pseudorabies

A

o Suid herpesvirus/aukeszky disease virus
 Lifelong carrier once infected

26
Q

Psuedorabies
- who does it affect
- where is it found
- how is it transmitted

A

o Can affect cattle/sheep/goats/dogs/cat/mink/fox/raccoon/rat
o Most countries except Canada
o Transmission: direct (nose-nose)/sexual/aerosol/fomites

27
Q

What is the pathologic mechanism of pseudo rabies

A

o Path: enter respiratory trance – spread via blood/lymph/nerves via retrograde transport from axon to cell body

28
Q

What are the clinical signs of pseudorabies at different age stages

A

o Clinically: age dependent
 Neonate/suckling pig: 100% mortality – paralysis, loss of appetite/vomiting/neurologic signs (convulsion/incoordination)
 Weaner: 5-10% mortality – respiratory (cough/sneeze)
 Grower/finisher: 1-2% mortality – respiratory disease
 Adult: mild/possible repro problems (SMEDI)

29
Q

What is the incubation period of pseudorabies

A

o Incubation: 2-5 day

30
Q

What are the gross lesions of pseudorabies

A

o Gross lesions: pulmonary edema/hemorrhage/gastric hemorrhage/hyperemia/necrosis/leptomeningeal hyperemia

31
Q

How does pseudorabies manifest in non-pigs?

A

o Non-swine clinical path: infect respiratory tract = spread via retrograde transport in nerves (no blood or lymph spread)
 Clinically: neuropathy itch: overwhelming puritis/self mutilation

32
Q

How to diagnose pseudorabies

A

o Dx: can isolate virus in 8 – 25 day via IHC
 Detectable antibody response for life

33
Q

How to control pseudorabies

A

 Eradicated in domestic populations (not wild) – lifelong infection
 Vaccination: deleted glycoprotein E in vaccine – serological assay for gE = can differentiate infected and vaccinated animals

34
Q

What is the family of influenza virus

A

orthhomyxoviridae

34
Q

What is the difference between influnza virus type and subtype

A
  • Many types A (animal/human), B (human/serologically in pigs), C (humans/ some seal/pig), D (cattle/seropositive humans), A (HA and NA subtypes)
    o Types based on internal proteins (nuclear protein and matrix protein)
35
Q

What are the clinical signs of swine influenza

A
  • Clinically: cough/nasal discharge/hyperthermia/reduce appetite/fever induced abortion
    o Receptors for human and avian influenza
    o 5-7 days for recovery (H1N1 = longer recovery time)
    o 100% morbidity, low mortality
36
Q

How is swine influenza transmitted

A
  • Transmission: nasal discharge/aerosol
37
Q

Where are swine influenza lesions found

A
  • Lesions: lung
38
Q

How to diagnose swine influenza

A
  • Dx: vial detection (nasal/tonsil swab, RT-PCR/sequencing, culture, IHC) serology (haemagglutination inhibition test/ELISA)
39
Q

How to control swine influenza

A
  • Control: vaccine
40
Q

How does HPAI impact pigs

A

minimally
out of a bunch infected only a few seropositive