NR AWNC
AU Sala,C.; Morignat,E.; Roy,P.; Ducrot,C.; Calavas,D.
TI Seasonality of exposure of cattle to BSE in France
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions RA-10
PT Konferenz-Poster
AB In order to detect a potential birth seasonal pattern of exposure for the risk of Bovine Spongiform Encephalopathy (BSE) in France, we fitted a logitic model adjusted for age at detection, birth cohort and month of birth. We used exhaustive BSE data provided by the screening plans in force in France since July 1st 2001. 640 BSE positive cases and 7,981 009 negative animals over 48 months, detected from July 1st 2001 through December 31st 2005, were included in the study. Age and birth cohort were categorized into 16 groups using 12 month intervals, while season of birth was taken into account on a monthly basis. Two logistic models were run, in which parameters were estimated by the maximum likelihood method, respectively for dairy cattle and beef cattle, because calving seasons and feeding patterns are different between these production types in France. Categories at risk of BSE for the age at detection and birth cohort factors were identical for dairy and beef cattle. BSE prevalence was maximal for animals aged from 60 to 83 months at detection and for cohorts born from July 1st 1993 to June 30th 1995 (birth cohorts 93/94 and 94/95) and decreased for latest birth cohorts. Dairy cattle born from July to September were significantly more at risk for BSE than those born in other months while BSE prevalence in beef cattle was significantly higher for August and November months of birth. Our results agreed with previous studies in the UK which evidenced a seasonal pattern of exposure, probably due to specific herd and feeding schemes. More detailed data about specific seasonal feeding practices and particularly consumption of concentrates could help understanding the epidemiology of the disease.
AD C. Sala, E. Morignat, D. Calavas: AFSSA Lyon, Unité Epidémiologie, Lyon, France; C. Ducrot: INRA Theix, Unité d'Epidémiologie Animale, Saint- Genès-Champanelle, France; P. Roy: Centre Hospitalo-Universitaire Lyon-Sud, Service de Biostatistique des Hospices Civils de Lyon, PierreBénite, France. E-mail: c.sala@lyon.afssa.fr
SP englisch
PO Italien
EA Poster, Übersicht 1, Übersicht 2, Tab. Milchrinder 1, Tab. Milchrinder 2, Tab. Mastrinder 1, Tab. Mastrinder 2, Handout