The effectiveness of routine serological surveillance: case study of the 1997 epidemic of classical swine fever in The Netherlands

The authors describe the value of routine serological surveillance in detecting the introduction of classical swine fever virus into a disease-free population. The first investigation concerned the question of whether the epidemic of classical swine fever (CSF), which occurred from 1997 to 1998 in the Netherlands, could have been detected using the existing monitoring system for notifiable diseases. The investigation used data from the CSF epidemic of 1997/1998 and from the existing monitoring system. Secondly, the probability of detecting a case of CSF using routine serological surveillance was modelled both for multiplier herds and for finishing herds, and then for different herd size categories. The first investigation concluded that the probability of detecting the epidemic at the current level of routine serological surveillance is very low. The second investigation concluded that even employing a sampling scheme of sixty blood samples per month, the probability of detecting an outbreak of CSF within forty days of the introduction of the virus, is less than 40%.