Impacts of Influenza virus in Danish swine herds

30-01-2018 CPH Pig seminar

DVM, Ph.d student Pia Ryt-Hansen

pryt@vet.dtu.dk

17/04/2008 Presentation name 2 DTU Vet, Technical University of Denmark

Background:

• Influenza A virus (IAV) is enzootic in swine herds globally

• Important co-factor in the Porcine Respiratory Disease Complex

• Leads to clinical signs of respiratory disease

• Increases the incidence of secondary diseases

• Recent studies:

– Persistence of IAV within the herd

– Questionable effect of maternal IAV antibodies from vaccinated sow

• Zoonotic potential

Denmark:

• 90 % of all sows from 150 herds had IAV antibodies

• 45 % of all diagnostics respiratory samples are IAV positive

– More subtypes in the same herd

– Herds test IAV positive continuously

– More attention to IAV as a major pathogen

– Vaccine sales have increased 350 % since 2010

17/04/2008 Presentation name 3 DTU Vet, Technical University of Denmark

Aim:

H1N1 H1N1pdm H3N2

H1N2

?

17/04/2008 Presentation name 4 DTU Vet, Technical University of Denmark

Aim:

17/04/2008 Presentation name 5 DTU Vet, Technical University of Denmark

Aim:

17/04/2008 Presentation name 6 DTU Vet, Technical University of Denmark

Aim:

17/04/2008 Presentation name 7 DTU Vet, Technical University of Denmark

Study design

2 weeks before farrowing

Week 1 Week 3 Week 5 Week 10-12

Sows: Blood sample Nasal swab

Offspring: Nasal swab Blood sample + Nasal swab

Nasal swab Blood sample + Nasal swab

17/04/2008 Presentation name 8 DTU Vet, Technical University of Denmark

Herds

Exclusion criteria:

• No SIV vaccination for minimum 1 year

• Cannot start up vaccination during the study

Inclusion criteria:

• Minimum 300 sows

• Production from 0-12 weeks of age

• Weekly production

• History of respiratory disease or laboratory confirmation of SIV

17/04/2008 Presentation name 9 DTU Vet, Technical University of Denmark

Herds

Herd 1: H1N2

• Non SPF

Herd 2: H1pdmN1pdm

• Blue SPF

Herd 3: H1N1av/H1N2

• Blue SPF + AP2 + Type 1

Herd 4: H1N2

• Blue SPF

1

2 3 4

17/04/2008 Presentation name 10 DTU Vet, Technical University of Denmark

Discussion: Endemically infected herds: Herd 1, 2 and 4

– Early infection - 3 days old piglets

– Infection in all sections

– Sow as a source of viral shedding in the farrowing unit

– Low level of persistent IAV shedders

– Infected piglets from IAV antibody positive sows – questionable effect of maternal antibodies:

• 98 % of all pigs becomes infected before week 8

– Vaccine efficacy?

» Future studies

17/04/2008 Presentation name 11 DTU Vet, Technical University of Denmark

Discussion: Acute outbreak with a new subtype in Herd 3

– Changed dynamics

– Infection limited to the farrowing unit – week one

– Large diversity of the HA gene within the same HA subtype

• Viral escape

• No protection of the piglets

– Vaccine efficacy?

» Future studies

– Internal biosecurity

• Limit movement of pigs

• All in all out

• No weaned piglets in the farrowing unit

• Sectioning of age groups

• No back-flow of pigs or personnel

• Vaccination of personal

• Quarantine

17/04/2008 Presentation name 12 DTU Vet, Technical University of Denmark

Acknowledgements: • DTU vet:

– Lars Erik Larsen

– Jesper Schak Krog

– Hue Thi Tranh Tran

– Nina Dam Grønnegaard

– Tine Skotte Hammer

• IDT Biologika:

– Inge Larsen

– Anja Kibsgaard

– Jens Dam

– Silke Wacheck

• SEGES Svineproduktion:

– Charlotte Sonne Kristensen

– Lotte Skade

– Kirsten Pihl

– Jane Rasmussen

• Besætninger:

– Ejere og medarbejdere (anonyme)

• Dyrlæger:

– Anders Elvstrøm

– Sten Larsen

– Gerben Hoornenborg

17/04/2008 Presentation name 13 DTU Vet, Technical University of Denmark

Questions?