1 / 18

BVDV-INFECTION-RISK IN THE COURSE OF THE VOLUNTARY BVDV-ERADICATION PROGRAM IN STYRIA/

BVDV-INFECTION-RISK IN THE COURSE OF THE VOLUNTARY BVDV-ERADICATION PROGRAM IN STYRIA/AUSTRIA. OBRITZHAUSER W. a,c , FUCHS, K. b , KÖFER, J. c a Veterinary Laboratory, A-8605 Parschlug, Austria

isra
Download Presentation

BVDV-INFECTION-RISK IN THE COURSE OF THE VOLUNTARY BVDV-ERADICATION PROGRAM IN STYRIA/

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. BVDV-INFECTION-RISK IN THE COURSE OF THE VOLUNTARY BVDV-ERADICATION PROGRAM IN STYRIA/AUSTRIA OBRITZHAUSER W.a,c, FUCHS, K.b, KÖFER, J.c a Veterinary Laboratory, A-8605 Parschlug, Austria b Institute for Applied Statistics and System Analysis, Joanneum Research, A-8010 Graz, Austria c Animal Health Service of the Department of Veterinary Administration, Styrian Provincial Government, A-8010 Graz, Austria

  2. BVDV-infection-risk Population of bovines in Styria (2003) Bovine herds 17,365 Cows (approx.) 147,000 on average 8.5 cows / herd Young stock (approx.) 190,000 Bovines total (approx.) 337,000 on average 19.4 bovines / herd

  3. BVDV-infection-risk BVDV-eradication in Styria (Scandinavian eradication scheme) 1998 Voluntary BVDV-eradication program 2001 Voluntary BVDV-eradication program in breeding herds 2004 Compulsory national BVDV-eradication program in Austria (01-Aug-2004) in all cattle herds (with the exeption of fattening herds)

  4. BVDV-infection-risk Voluntary BVDV-eradication program in breeding herds 2001 - 2004 • Tests for BVDV (antibodies, BVD-virus) of all animals intended for common pastures (since March 2001) • Tests for BVDV (antibodies, BVD-virus) of all animals intended for breeding market places (since 2001) • Repeated bulk milk tests for antibodies to BVDV (2001 – 2004: 2 times a year in breeding herds only)

  5. BVDV-infection-risk Voluntary BVDV-eradication program in breeding herds 2001 - 2004 • Repeated spot tests to identify/monitor „presumably non-infected“ herds (depending on bulk milk test results) • Investigations for BVDV in herds identified as „possibly infected“; removal of the PI-animals • Follow-up tests of all calves born during one year after removal of the last PI from the herd • Certification of herds which proved to be free of BVDV

  6. BVDV-infection-risk Voluntary BVDV-eradication program in breeding herds 2001 – 2004(3) (1) 30-06-2004 (2) 31-07-2004 (3) 01-01-2001 – 31-07-2004

  7. cattle markets breeding herds(covered by the BVDV- eradication program) non-breeding herds (not covered by the BVDV- eradication program) common pastures purchase & trade import exhibitions import BVDV-infection-risk fattening herds (not covered by the BVDV-eradication program)

  8. Breeding Organisations epidem. data Ab/Ag-ELISA results ..... ..... ..... bulk milk ELISA results ..... ..... ..... markets report Ab/Ag tests ..... ..... ..... ..... Sampl. report auctions common pastures ..... result bulk milk- test ..... ..... Sampl. data sheet ..... ..... ..... report BVD- status ..... ..... ..... ..... result Ab/Ag tests ..... ..... ..... ..... report PI-animals ..... ..... ..... ..... Sampl. control report ..... ..... ..... ..... Summ. test results ..... ..... ..... ..... BVDV-infection-risk BVD-database ELISA-READER (WinRead) AMA- database common pastures Process Controll herds ..... ..... ..... ..... ..... ..... reports process controll ..... ..... ..... animals ..... ..... ..... ..... ..... ..... VETGIS screens

  9. BVDV-infection-risk BVDV-infected herds* - BVDV-eradication program in Styria * herds are grouped as BVDV-infected untill 1 year after iden-tification of the last PI-animal in the herd

  10. BVDV-infection-risk First identified PI per BVDV-infected breeding herd – month of birth

  11. BVDV-infection-risk How does BVDV-infection-risk develop ... • in the course of a voluntary BVDV-eradication program ? • Scandinavian eradication sheme • Eradication without vaccination • in a cattle-population which is only in part covered by the BVDV-eradication program ? • 4,412 breeding herds (25.4 % of all cattle herds in Styria) • 147,000 cattle (43.6 % of all bovines in Styria) • in a cattle-population in which putting cattle to common pastures and purchase of cattle is widespread ? • 35,000 cattle from 4,100 herds put to common pastures per season • Up to 26,000 cattle (10,500 female, 15,500 male) are purchased

  12. BVDV-infection-risk Risk assessment Exposures: • Common pastures • Cattle trade (purchase) • BVD-control program (overall risk) Periods of time: • Time before the beginning of the BVDV-eradication program (2001) compared to the first 30 months after the implementation of the BVDV-eradication program (2003) • For the period from Aug-2002 to Jul-2003 compared to the period from Aug-2003 to Jul-2004

  13. BVDV-infection-risk Measures of risk • RISK RATIO (RR) Relative measure of the difference in risk between the exposed and unexposed population. Def.:The rate of disease among the exposed divided by the rate of the diseased among the unexposed. A relative risk of 2 means that the exposed group has twice the disease risk as the unexposed group. • ODDS RATIO (OR) Way of assessing whether the probability of a certain event is the same for two groups. Def.: Odds of diseased being exposed divided by odds of not diseased being exposed. An odds ratio greater than one implies that the event is more likely in the first group. An odds ratio less than one implies that the event is less likely in the first group. RR = a * (c + d) / c * (a + b) OR = (a / c) / (b / d) 95% CI = 95% confidence-intervall

  14. BVDV-infection-risk RR/OR for breeding herds in Styria - overall risk before and after the implementation of the BVDV-eradication program • In 2001 the overall risk of BVDV-infections in breeding herds in Styria appeared to be 5 - 9 times higher than after the implementation of the BVDV-eradication program. * first 30 months 95% CI: [ 4.79 – 8.20] RR = 6.27 * OR = 6.81 * 95% CI: [ 5.16 – 8.97] * = p < 0,05

  15. BVDV-infection-risk Odds-Ratio (OR) and Risk Ratio (RR) for breeding herds before compared to the first 30 months after the implementation of the BVDV-eradication program 95 %-CI = confidence intervall LL = lower limit UL = upper limit p < 0,05 = significant

  16. BVDV-infection-risk Odds-Ratio (OR) and Risk Ratio (RR) for breeding herds period Aug-2002 to Jul-2003 compared to period Aug-2003 to Jul-2004 95 %-CI = confidence intervall LL = lower limit UL = upper limit p < 0,05 = significant

  17. BVDV-infection-risk Odds-Ratio (OR) and Risk Ratio (RR) for exposed breeding herds compared to not-exposed breeding herds 95 %-CI = confidence intervall LL = lower limit UL = upper limit p < 0,05 = significant n.s. = not significant

  18. BVDV-infection-risk Conclusion: • The BVDV-eradication program in Styria was successful in decreasing the BVDV-infection risk significantly • New BVDV-infections could not be totally ruled out under the conditions of the voluntary BVDV-eradication program in Styria • New infections could be explained in almost all cases by incom-pliance with the conditions of the BVDV-eradication program • A further decrease of the risk of BVDV-infections requires the introduction of a compulsory BVDV-eradication program for all herds

More Related