PCV2 impact on early stage of gestation in sows: experimental results

Giuseppe Sarli

3rd Merial Forum – Malta - April 15th 2011

Target …..

• Results of a study conducted in 2009

CONVENTIONAL SOWS INSEMINATED WITH PCV2 INFECTED SEMEN

• IPVS Meeting 2010• ESPHM Meeting 2010

Objectives of the study

• Assessment of pathological consequences of PCV2 infection in conventional sows by infected semen

• PCV2 distribution and tissue lesions– sow genital tract– placenta– fetuses

1. Field condition2. Schmoll et al., 2008

(18.2% semen samples positive)

Experimental designControl PCV2

infectedSamplesanalysis

D0 AI

PCV2 semen

10 ml

PCV2 semen

10 ml3.2*105TCID50/ml

Cervix, nasal, rectal swabs and blood sample every week

D29 Ultrasonography

D30/D47 Euthanasia of empty sows

Sow: uterus, lymph nodes placenta; Fetus: lung, amniotic fluid, heart, liver

RtPCRHistology, IHC

D52 /D56

Euthanasia of pregnant sows

Experimental design

• Daily recordings (2/day)– body T°– clinical signs

• Weekly sampling– nasal, rectal, cervix swabs

• -2, 7, 14, 21, …. DPI• PCV2, PPV, PRRSV

– blood• -2, 7, 21, ……. DPI• PCV2, PPV, PRRSV, P4 titration

• Ultrasonography at 28 DPI

Results

• Infected group (6 sows)– 3 not pregnant – 3 pregnant

• Control group (3 sows)– 3 pregnant

Results: progesterone profiles

0

5

10

15

20

25

30

35

40

-2 7 21 28

DPI

P4 (n

g/m

l)

0

5

10

15

20

25

30

35

40

-2 7 21 28 35 42

N°33 N°27 N°32

Pregnant sows Not pregnant sows

Results: anti-PCV2 antibodies

Infected group

Control group

Infected Control

Pregnant Not pregnant Pregnant

Sow 25 26 29 27 32 33 28 30 31

Number of fetuses 16 11 7 0 0 0 11 0* 8

PCV2 antibodies before AI 1/102 1/103 1/103 1/104 1/104 1/103 1/103 1/104 1/104

Viremia at DPI 21,35 - 21 7 28 - - - -

Tonsil - - - + - - - - -

Uterine left lymph node (LN) + - - - - - - - -

Uterine right LN + - - + - - - - -

Tracheo-bronchial LN + - - - - - -

Cervix - - - - + - - - -

Fetuses (/tot.) 10/16 - 3/7 - - - - - -

Amniotic fluids (/tot.) - 1/11 - - - - - - -

Fetus and left uterine tract 7 - - - - + - - -

Fetus and right uterine tract 1 - - - - - - - -

Results

Results: tissues PCV2 viral load

• Sows– 103 to 5.4 x106 copies/ml

• Fetuses– a peak of 4x108 genome

copies/ml (sow 25, fetus n°16)

Results: histology

• Histology: placenta fetus n°16 sow 25– multifocal coagulative necrosis of

epithelium of chorion

• IHC placenta and liver, fetus 16, sow 25– multifocal, mild positivity of

chorion cells– multifocal, light positivity of

hepatocytes

• 3 out of 6 infected sows were not pregnant

• 4 out of the 6 infected sows developed viremia

• Viremia was longer in the sow with the lowest anti-PCV2 antibody level

• In at least one organ of the six infected sows PCV2 was detected

• The sow with the lowest anti-PCV2 antibody titre showed the higher number of positive tissues and fetuses

Summarizing the results …..

• In case of positive PCR results in the litter, a variable number of fetuses were positive

• PCV2 does not replicate only in foetal tissues

multifocal necrosis in chorionic epithelium

Summarizing the results …..

Conclusion

• PCV2 infection by intra uterine route– Conventional sows– Low anti-PCV2 levels viremia

• PCV2 infection close to AI– fertility

• Cervix swabs– not a relevant method

Conclusions

• PCV2 replicates in chorionic epithelium

• Placenta lesions

• Fœtal viral load

• Not all fetuses are PCV2 whole litter to be sent to the lab!

Fetus damage

Acknowledgments

• Dept. Veterinary Medical Science – Bologna

– Ostanello Fabio– Morandi Federico– Bacci Barbara– Panarese Serena– Fusaro Laura– Ferrara Domenico– Bacci Maria Laura– Govoni Nadia– Galeati Giovanna

• IZSLER

– Dottori Roberto

– Bonilauri Paolo

– Cordioli Paolo

– Lelli Davide

• Merial – Joisel Francois

– Thais Vila

Reggio Emilia

Brescia

Infectious diseases LS

Pathology LS

Physiology LS

Lyon

Thank you for your attention

Giuseppe SarliDepartment of Veterinary Medical Science

giuseppe.sarli@unibo.it

www.unibo.it