188. Differential diagnosis of infectious abortions of swine (epidemiology, clinical signs, post mortem lesions).

Question 1

Viral diseases causes?

Answer 1

Viral Diseases

1. PPV1
2. PRRS
3. Pseudorabies
4. PCV2
5. ASF
6. CSF
7. Influenza
8. Japan encephalitis
9. BVD
10. Border disease
11. Enterovirus
12. Encephalomyocarditis
13. High fever causes abortion

Question 2

Clinical signs?

Answer 2

Clinical Signs

• Infertility
• Stillbirth
• Mummification
• Weak piglets
• Agalactia
• Embryonic death
• Litter increase
• Detachment of sperm

Question 3

Pseudorabies?

Answer 3

Pseudorabies

Acute Form

• Virulent strains first infect an un-vaccinated susceptible herd
• The virus crosses the uterus and placenta and infects the foetuses
• Abortions, stillbirths and the birth of weak litters (soon die)
• Abortions 5% (reproductive failure at all stages of the cycle)

In immunised herds clinical signs are sporadic and milder:

• Depression of reproductive efficiency: infertility, mummification, stillbirths and piglet mortality
• Young carrier females shed virus → maintaining infection, spread of infection low with immunity
• Infection waning and rising over one to two year cycles

Question 4

PRRS Clinical signs?

Answer 4

PRRS

Clinical Signs

Abortion:

Usually the third trimester

No clinical sign till abortion

After: fever anorexia, lethargy, agalactia

30-35% of sows in a herd

Piglets:

Embryonic death

Mummification

Weak (alive to 1-2 weeks)

Neonates:

Splayleg

Respiratory signs, oedema around the eye, conjunctivitis

Clinical signs: till 1-12 months

Boar:

Detract of sperm

Respiratory signs

Question 5

Post Mortem signs and diagnosis of PRRS?

Answer 5

Post Mortem Signs

In foetus no pathognomic

Diagnosis

Clinical, pathological and histopathological signs and lab test

Identification:

RT-PCR

IF, IP

Serology:

ELISA, IF

Serum pair examination

Question 6

PPV1 Info?

Answer 6

PPV1

• Infection may disappear spontaneously in herds below 100 sows
• Endemic in most herds
• Infection induces lifelong immunity
• Reproductive problems may return every 3-4 years
• Abortus is not typical, no calcification so absorption of embryo is easy

Question 7

Clinical signs and PM lesions of PPV1?

Answer 7

Clinical signs

• Pregnant Sows:
• Return to oestrus (3-8 weeks after breeding)
• Abortus, smaller than normal litters
• PPV unlikely if at least 8 live pigs
• Embryo and Foetus:
• To 30 days: death, resorption
• 30-70 days: death of foetus, mummification, calcification of bones after 35 days, cannot be resorbed
• From 70 days: weak and mummified foetus, Myoclonia congenita, active immunity initiated after day 70
• Adults:
• Respiratory disease
• Vesicular disease
• Rarely
• Neonates:
• Systemic disease

Post Mortem Lesions

• Not uniquely characteristic to PPV1
• Foetal development disorders
• Piglets in different stages of infection
• Subcutan haemorrhage
• Mummification
• Effusion (sera, blood)
• Enlarged liver and kidney

Question 8

PCV2 Reproduction disorders?

Answer 8

PCV2 Reproduction Disorders

• The main target of the virus in the foetus is heart muscle cells
• More sever lesions in foetus of sow infected before day 70 of pregnancy (abortus, mummification, embryonic death)
• After day 70: immune response of the foetus, but reproductive problems remain
• Criteria of the diagnosis:
• Abortus towards the end of pregnancy or dead pigs born with enlarged heart
• Extensive fibrosis in the heart of foetus or necrotic myocarditis
• High virus load in myocardium and other tissues.

Question 9

Bacterial diseases?

Answer 9

Bacterial Diseases

1. Erisipelas
2. Streptococcosis
3. Staphylococcosis
4. Trueperella pyogenes
5. Brucellosis
6. Leptospirosis (L. pomona, L. tarassovi) – fetuses of different sizes

• Eperythrozoonosis
• Always send the foetus, foetal membranes and blood samples for diagnosis in all cases!!