Topic 11: PMWS of Swine

Question 1

Porcine Circoviruses - General

PMWS

Answer 1

Circovirus genus

PCV1, non pathogenic
PCV2 responsible for associated diseases, endemic WW

• post weaning multisystemic wasting syndrome
  endemic asia and epidemic
  sporadic, NA

Both found in wild boars

Features of PCV2 
- strongly immunosuppressive virus 
- activate diummune system helps progression of the virus 
- constantly changing genetically 
genotypes a, b,c exist 

Reservoir species: wild boar, rodent
Vx amiable for at was 3 years

Question 2

Diseases caused by PCV2 / PCVD (associated diseases)

Answer 2

PMWS, post weaning multi systemic wasting syndrome
PDNS, porcine dermatitis and nephritis syndrome
PRDC, porcine respiratory disease complex
PRF, Porcine reproductive failure
PGE, porcine granulomatous enteritis
PNL, porcine necrotising lymphadenitis
PCT, Porcine congenital tumour
PEE, Porcine exudative epidermititis

Question 3

PMWS Epidemiology

Answer 3

endemic in asia, europ, sporadic in NA

PCV2, main feature is damage to the immune system

Lympocyte depletion of lymphoid tissue, changes in peripheral blood mononuclear cell populations and altered cytokine expression patterns

affects swine btw 1.5-4 months (5-25w of age)

transmission: nasal secretions, faeces, urine and sperm etc

Question 4

Pathogenesis of PMWS

Answer 4

Oronasal infection, replication in macrophages, APC, epithelial cells , vireamia, systemic infection

Spreads within monocytes

Replicates in dividing cells, thymus, spleen, liver, BM, kidney, heart brain, monocytes, macrophages

LOW serum and tissue titres –> subclinical infects
CD8+ decreases then reverse, mild, or no changes in organs

MEDIUM / HIGH –> PMWS
- lymphoid organs, general lymphoid depletion, histiocyte infiltration
- macroscopic atrophy of the thymus
2º lymph organs, decrease of B and T cells, phagocytes, Neu, and Gran, dec CD4 and CD8 (IFN, IL2, IL4, IL10)
- organs, pneumonia, hepatitis, and enteritis

Blood, dec B and T cells NK cells, increased monocytes and granulocytes

Potentiators; immune activation, vaccines, other viral infections, immunomodulatora, viral strain, genetic background

Question 5

CS of PMWS

Answer 5

UNCUBATION: 2-4 WEEKS
MORBODOTY 20-30% @5-12 weeks
ranges from sudden death to slow wasting
commonly involves other enteric diseases (watery scour) or resp signs, coughing, tachypnoea

anemia, cyanosis, Neuro signs

Non specific is often, fever, lethargy, jaundice, rough hair coatrack

symptoms of co infections