NR AWGV
AU Heres,L.; Elbers,A.R.; van Zijderveld,F.G.
TI Clinical symptoms reported - and decrease in milk production - of BSE affected cows detected by active surveillance in The Netherlands
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 EPI-05
PT Konferenz-Poster
AB Active BSE surveillance by testing all slaughtered cows and fallen stock is a strong tool to estimate the BSE prevalence. Introduction of active surveillance mostly results in an increase of detected cases. We present data that underline the assumption that passive surveillance underestimates the number of cases with clinical signs. Ninety percent of the BSE case farms in The Netherlands participated in a case-control study. A part of the questionnaire used in this study concerned the clinical symptoms observed by the farmers. Also milk production records were asked for BSE cows and within-farm control cows matched by parity. The number of notified clinically suspected cows in The Netherlands was first low and increased in 1996 and 2001, presumably as a consequence of the increased awareness of farmers and veterinarians in these years. In these specific years BSE was a news media topic and new control measures were implemented. The reports about clinical signs collected during interviews of farmers show that 14 out of 16 fallen stock and 19 out of 36 slaughtered animals had clinical symptoms at hind sight. Milk production records show a significant decrease in the last lactation of BSE cows. Due to the a-specific nature of many of the BSE symptoms, especially at the beginning of the clinical stage of the disease, clinical detection can be difficult. The effectiveness of a passive surveillance system for BSE is therefore strongly depending on awareness of farmers and veterinarians that BSE could occur, their willingness to report cases even if the diagnosis is not evident, their feeling of urgency to report clinical suspects and their knowledge of clinical symptoms. The present results underline that estimated prevalence or absence of BSE in a certain country could very well be underestimated when based on passive surveillance.
AD Dept. Bacteriology & TSEs, CIDC-Lelystad, Wageningen UR, Lelystad, The Netherlands. E-mail: lourens.heres@wur.nl
SP englisch
PO Italien