Infections of the pig

1
Infections of the pig
2
Viral infections of the respiratory tract

• PRRS
• Cirkovirus (PCV2)
• Aujeszky disease - Pseudorabies
• Inclusion rhinitis
• Swine influenza

3
Porcine Reproductive and Respiratory disease
syndrome virus
PRRS

• Affinitou to respiratory ang genital system
• Antigennic variability, european and american
  genotypes
• Strains differ in virulence

4
Pathogenesis
PRRS

• Infection by inhalationaerosol
• Alveolar macrophage are target cells for primary
  replication
• Respiratory signs are apparent in piglets older
  than 3 weeks
• Antibodies can enhance virus infection

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Pathological changes
PRRS

• Periocullar oedema, conjunctivitis, blue
  coloration of eyes, vulva and snout
• Interstitial pneumonia, loss of cilliar
  epithelial cells

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Porcine Circovirus 2
PCV-2

• PMWS (Postweaning Multisystemic Wasting Syndrome)

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Clinical signs
PCV-2

• Affected age category 5 12 weeks
• Respiratory signs
• Growth retardation
• Enlargement of lymph nodes
• Anemia, icterus
• Fever

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PMWS (Postweaning Multisystemic Wasting
Syndrome)
PDNS (Porcine Dermatitis and Nephropathy
Syndrome)
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Pathogenesis is still unclear !!
Immunosupression
PMWS
PCV-2 immunomodulation PMWS
10
Immunosupression in PCV2 infection

• Lymphoid depletion
• Loss of lymphatic follicles
• Atrophy of lymphatic organs
• Loss of circulating B and T lymphocytes
• Secondary infection
• Doesnt produce antibodies
• Doesnt respond to vaccination

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PRDC PCV2

• Porcine respiratory disease complex syndrome
• Multiethiological
• Age category 16 or more weeks
• Virus is in the lung tissue, no PA changes in
  lymphonodes

12
Swine influenza

• Acute, febrile disease
• Cough, fever, ocullar and nasal discharge
• Very short incubation period
• Colostral antibodies doesnt protect agains
  disease

13
Aujeszky disease- Pseudorabies

• Pig is the primary host and the reservoior for
  the virus
• Respiratory transmission
• Incubation period 2-3 days
• Primary replication in oropharynx
• Latency in g. trigeminale

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Aujeszky disease- Pseudorabies

• Fever, anorexia, vomiting, ataxia, respiratory
  signs
• Pneumonia
• Necrotizing tonsilitis
• Keratoconjunktivitis

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Bacterial infections in the respiratory system
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The upper respiratory tract I.

• Non progresive rhinitis atrophicans
  (bordetelosis)
• Bordetella bronchiseptica
• progresive rhinitis atrophicans (toxinogennic
  pasteurellosis)
• Pasteurella multocida
• (dermonecrotoxin- positive strains)

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The lower respiratory tract II. - pneumonia

• enzootic pneumonia
• Mycoplasma hyopneumoniae
• M.hyorhinis
• (acute pasteurellosis)
• P. multocida type A, D,.
• Bordetella bronchiseptica
• (piglets older than 3 or 4 days)
• Arcanobacterium pyogenes
• Streptococcus suis (serovars 2,1, 7)

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The lower respiratory tract III.

• Pleuropneumonia (peracute or acute)
• A.pleuropneumoniae (serovars 7,9,11)
• chronic pleuropneumonia
• A.pleuropneumoniae (serovar 2)
• Pleuritis
• Haemophilus parasuis

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Viral diseases of the urogenital system

• Porcine Parvovirus
• PRRS
• Pseudorabies
• Porcine Circovirus 2
• La piedad virus

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PRRS

• Abortions, premature delivery, weak piglets,
  agalactia
• Late pregnancy
• Virus is disseminated by infected macrophages
• Placenta is not permeabile till the ½ of the
  pregnancy
• No macroscopic changes on aborted piglets

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Pathogenesis
PCV-2

• Incubation period 7 10 days
• Maximal virus shedding 3. 13. days p.i.
• Length of shedding 10 35 days, urine, feces,
  semen, nasal secretions

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Circovirus diseases

• Virus is present in the semen of boars
• Transplacental infection
• Abortions
• Mumification
• Dead piglets

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Affected age categories
PCV-2
PRRS

• Piglets
• PMWS
• PDNS
• PRDC
• Secondary infection
• Sows
• Reproductive signs

• Piglets
• Pneumonia
• PRDC
• Secondary infection
• Sows
• Reproductive signs
• Boars

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Virus shedding
PCV-2
PRRS

• Respiratory route
• Contact
• Orofecal transmission
• Transplacental infection
• Shedding in the semen

• Respiratory route
• Contact
• Transplacental infection
• Shedding in the semen

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Diagnostics
PCV-2
PRRS

• Virus quantification
• Detection of antobodies - sensless

• Virus detection (RT-PCR)
• Detection of antibodies

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Porcine Parvovirus

• Enzootic
• Infection by oronasal route, shedding in feces
  last for at least 14 days
• Viremia transplacental infection
• abortions, mumification
• Only one piglets from the litter can be affected
• Infection in adult animals in inapparent

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Aujeszkyho disease - Pseudorabies

• Abortions in sows, stillbirth or mumification
• Infection is followed by infections in 10 days
• Periorchitis in boars

28
Porcine Enterovirus

• SMEDI syndrome

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THE URINARY SYSTEM

• cystitis
• E.coli
• cyto-pyelonephritis
• Actinobaculum suis
• E.coli

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THE REPRODUCTIVE SYSTEM

• abortions
• Leptospira icterohaemorrhagiae
• Haemophilus parasuis
• endometritis/metritis
• co-infection with G- bacteria
• E.coli, Pasteurella spp.,

31
Viral infections of enteric tract

• Transmissible gastroenteritis virus
• Swine Rotavirus
• Classical swine fever virus
• Vesicular stomatitis virus

32
Transmissible gastroenteritis virus

• Enzootic disease
• Coronavirus with tropism to mature enterocytes
• Oral infection
• Sudden onset, incubation period 2-3 days
• Malabsorption syndrome, watery diarrhoea
• High mortality (2-3 days p.i.) decrease with age
  (till 14 days - almost 100)

33
Transmissible gastroenteritis virus

• Systemic antibodies doesnt protect
• Lactogennic immunity (IgA) is necessary

34
Porcine Rotavirus

• Ubikvitous virus
• Host specificity, cross reactivity
• Critical period
• 1 3 weeks
• 2-7 days post weaning
• White, yellow watery diarrhoea
• Pathogenesis is similar to TGE

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Bacterial infections in THE ALIMENTARY TRACT
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THE ALIMENTARY TRACT I.

• necrotic stomatitis
• Fusobacterium necroforum,
• Staphylococcus aureus
• gastritis
• Helicobacter suis ??

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THE ALIMENTARY TRACT II.

• Enteritis /enterotoxicosis/enterotoxemia/
• colibacillosis
• neonatal diarrhoea, E.coli F4, F5, F6, ST, LT
  positive
• E.coli (ETEC,ETEEC) postweaning diarrhoea E.
  coli F18, F4
• Oedema diseases, E. coli VT positive (VTEC)
  isolates
• necrotic enteritis in piglets C. perfringens
  type A , cpb2
• Haemorrhagic enetritis
• C. perfringens typ C
• Salmonella Typhimurium
• Salmonella Choleraesuis

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THE ALIMENTARY TARCT III.

• Bacillus cereus, enterotoxines positive strains
  (ET).
• proliferative enteropathy ("ileitis")
• Lawsonia intracellularis
• swine dysentery
• Brachyspira hyodysenteriae
• colonic spirochaetosis
• Brachyspira pilosicoli
• polyserositis and peritonitis
• H.parasuis
• M.hyopneumoniae

39
Viral infections of CNS

• Pseudorabies
• Porcine Enterovirus (Teschovirus)
• Nipah virus

40
THE CENTRAL NERVOUS SYSTEM

• meningo-encephalitis
• Streptococcus suis type 2
• Haemophilus parasuis
• Salmonella Choleraesuis
• Listeria monocytogenes

41
Porcine Teschovirus

• Picornavirus
• Polioencephalomyelitis, frequent inapparent
  infections
• Highly virulen strains are causing (serotype 1)
  Teschen disease with high mortality
• Replication in the gut and mononuclear cells of
  Lamina propria, hematogenous spread to CNS
• Fever, ataxia, convulsions, paralysis

42
Pseudorabies

• In piglets only
• Depression, ataxia, tremor, convulsion, pruritus
• Nonpurulent meningoencephalitis and
  ganglioneuritis

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THE BLOOD

• SEPTICEMIA
• Salmonella Choleraesuis
• E.rhusiopathiae
• Streptococcus suis type 1,2
• S. equi subsp. equisimilis, S. porcinus
  
• Actinobacillus suis,
• A.pleuropneumoniae,
• H.parasuis
• E.coli
• endocarditis
• Streptococcus suis ,
• A.pleuropneumoniae
• E.rhusiopathiae

44
THE MUSCULOSKELETAL SYSTEM

• artritis-polyartritis
• Streptococcus suis, type 1
• S.dysgalactiae,
• H.parasuis
• Mycoplasma hyosinoviae,
• M.hyorhinis
• Actinobacillus suis
• Arcanobacterium pyogenes, E.rhusiopathiae

45
Virus infections of the skin

• Porcine Circovirus 2
• Porcine poxvirus
• Foot and mouth disease virus
• Vesicular exanthema virus
• Porcine Vesicular disease

46
THE SKIN

• Exudative epidermitis
• Staphylococcus hyicus
• Pustular dermatitis
• Staphylococcus aureus
• Erysipelas
• E. rhusiopathiae
• absceses
• Actinomyces pyogenes,
• S.porcinus, F.necroforum