Preventing CSF re-emergence: a continuous challenge

Transcription

1 Preventing CSF re-emergence: a continuous challenge Dr Frank Koenen CODA-CERVA-VAR

2 CSF characteristics Virus characteristics Small enveloped RNA virus Member of Genus pestivirus with BVDV and BDV Disease characteristics Clinical picture has changed from acute to sub-acute or even subclinical An isolate can induce different clinical pictures Last 20 years only sporadic epidemics in domestic pigs (EU 15)

3 Economical impact Economic and socio-economic impact is very high worldwide epidemic: 21.4 millon for outbreaks and 130 million for market support 1997 epidemic: 10 million pigs slaughtered, total costs 1 billion 2006: small outbreak: pigs culled

4 Detection-Monitoring- Intervention strategy Detection: Clinical detection can be difficult Laboratory detection: IF, VI, ELISA, real time PCR Monitoring: Sampling schemes are available Intervention strategy: Modified live vaccine (C-strain) Sub-unit marker vaccine Stamping out

5 High risk period (HRP) Country Year Estimated HRP-1 (weeks) United Kingdom The Netherlands Belgium Germany Spain Elbers et al., 1999

6 Introduction - Transmission In contrast to an unknown emerging disease a lot of information is available. Factors and circumstances affecting introduction: Animal trade, including import of wildlife Geographical proximity Tourists Hunters Tourist-illegal import of food Swill Factors influencing spread and transmission: Oro-Nasal contact Animal transport Intense trade (no vertical structure) High pig density (air?) Semen People Poor hygiene and lack of biosecurity

7 Will CSF re-emerge? Probably yes!

8 Why?

9 Why? Historical cycle: 9 years Presence worldwide Changing factors

10 CSF in the world

11 CSF in Europe

12 Changing factors Farming and trading system Contact structures Wildlife management Geo political decisions influencing trade structures Increased awareness of bio security

13 CSF in Wild boar

14 Wild boar population Population increased dramatically during the last decades Wild boar density is recognised as one of the most relevant risk factors for CSF 80% of the first outbreaks of CSF in domestic pigs in regions where CSF is endemic in Wild boar

15 CSF control strategies in wild boar Hunting Oral vaccination with C-strain Unclear strategy When? Before or after outbreak? Where? Which region? Frequency? Once, multiple?

16 Backyard pigs Freerange: Pigs spend the day looking for food (cultivated corn, bulbs, fruit-trees, garbage) and water When they come back home in the morning they are feeded with a small portion of corn or waste.

17 Backyard pigs Important economical factor in new member states. Home consumption: from 1 to 15 pigs. It is a production for family consumption and usually it consists of one pig or, in the best cases, two sows with their piglets. Small producers: from 16 to 40 pigs. It is a production for the family consumption and to sell the leftovers..

18 Backyard pigs Sanitary status: CSF is endemic Asymptomatic carriers (CSF, PRRS) Reservoirs of parasitic, zoonotic diseases Management: Not individually identified Any kind of registration No possibility to measure birth, mortality or morbidity rates Vaccination program: Not all the individuals in the population are vaccinated.

19 How to avoid re-emergence?

20 Increase knowledge Decrease HRP Database Mathematical disease spread models can provide appropriate tools for: Disease vigilance Evaluating control options Estimate the number of infected farms after a CSF introduction Estimate the effect of different herd types on disease spread Make predictions about the expected geographical distribution of infections Live marker vaccine

21 Decrease HRP Improve early detection: Education Hand computer Personal Digital Assistant (PDA) with data-entry screen (Elbers)

22 Data transfer GPRS Farm Data in attachment sent by PDA via Internet Possibility for sending back CSFprobability to practitioner within minutes after receiving clinical data Calculation of CSF-probability on PC (in future on PDA) Intake of data in e- mail message by Computer-server at University of Utrecht

23 EU Data base Central CSF Data Base (data, questionnaires, web server) Departments Districts Vaccina tion Virus Virolo gy Age Serolo gy Departments Districts Laboratories Ministries (BMVEL) Scientific Institutes Ministries Competent Land Authorities

24 Follow up of CSF Domestic pigs: 011 Wild boar: 3451

25 Modelling Ribbens and Dewulf

26 Results- hobby Ribbens and Dewulf

27 Results- regular Ribbens and Dewulf

28 Results- High contact Ribbens and Dewulf

29 Wild boar Management: Hunting

30 Wild boar Management: Vaccination (20%)

31 Wild boar Management: vaccination (40%)

32 Conclusions CSF management in wild boar In a single population with < 1000 to 1500 wild boar: The disease will fade out. Random interaction Hunting + Vaccination: Endemic evolution in 4% of the cases Optimal vaccination condition: Start vaccination at 150 days after virus infection Immunize at least 40% of all susceptible animals Hunting should NOT exceed 45% of the whole population

33 Live Marker Vaccine development New candidate selected for application in wild boar Several other chimera and back up available Possibility to study vaccine characteristics Evaluation towards vaccine: Formulation of the product as a vaccine for oral application Safety studies Potency studies Onset of immunity

34 Conclusions Known agent: Preparedness in order to limit the HRP: Education Monitoring Real time exercise But! Situation changes New threats Available tools change or can be adapted Research: Improve existing tools Develop new tools Update the knowledge concerning environmental changes

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