Distribution of Schmallenberg virus and seroprevalence in Belgian sheep and goats

A serological survey to detect Schmallenberg virus (SBV)-specific antibodies by ELISA was organized in the Belgian sheep population to study the seroprevalence at the end of the epidemic. One thousand eighty-two sheep samples which were collected from 83 herds all over Belgium between November 2011 and April 2012 were tested. The overall within-herd seroprevalence and the intraclass correlation coefficient were estimated at 84.31% (95% CI: 84.19-84.43) and 0.34, respectively. The overall between-herd seroprevalence was 98.03% (95% CI: 97.86-98.18). A spatial cluster analysis identified a cluster of six farms with significantly lower within-herd seroprevalence in the south of Belgium compared with the rest of the population (P = 0.04). It was shown that seroprevalence was associated to flock density and that the latter explained the presence of the spatial cluster. Additionally, 142 goat samples from eight different herds were tested for SBV-specific antibodies. The within-herd seroprevalence in goats was estimated at 40.68% (95% CI: 23.57-60.4%). The results of the current study provided evidence that almost every Belgian sheep herd has been in contact with SBV during 2011 and should be taken into consideration as part of comprehensive SBV surveillance and control strategies

The role of the infection status of sows on the assignment as Salmonella risk farm in the Belgian Salmonella control program

Salmonella surveillance and control programs arc generally based on results of samples taken from the fattening pigs and intervention measures are limited to the fattening unit. To evaluate the role of the sows in the assignment as Salmonella risk herd we compared the serological status from sows at risk herds to the status of sows at non-risk farms. From this study it is clear that the role of the sows and their serological Salmonella status is a potential influencing factor for the assignment of Salmonella risk farms in the Belgian Salmonella control program, which is principally based on sampling of fattening pigs. More insight in the role of the sow as a reservoir for Salmonella infections might help to define important intervention measures at pre-harvest stage

Transmission study of Salmonella in pigs with 3 intervention strategies

In this study, the effect of 3 different intervention strategies on the transmission of Salmonella in pigs was evaluated: feed supplementation with coated calcium-butyrate salt, vaccination and acidified drinking water. Strategies were evaluated serologically and bacteriologically using an experimental in vivo seeder setup. Significantly higher antibody titers were detected in the groups with acidified drinking water and vaccination

Bacteriological prevalence in finishing pig farms assigned as Salmonella risk farms by serological screening

The Belgian Federal Agency for the Safety of the Food Chain (FASFC) installed a National Salmonella surveillance and control program in pigs, the Salmonella Action Plan (SAP), which became compulsory by means of a Royal act in July 2007. Assignment as Salmonella risk farm is based on serological analysis of blood samples collected from the fattening pigs. The knowledge of prevailing serovars of Salmonella by bacteriological methods is essential to develop and/or evaluate the serological method. In 57% of all the assigned farms, based on serological screening (~ mean SIP-ratio\u27s), there is \u27firm evidence\u27 by bacteriological isolation. This suggests that a sufficient correlation is achieved at herd level in the first stage of the Salmonella Action Plan

The role of the infection status of sows on the assignment as Salmonella risk farm in the Belgian Salmonella control program

Salmonella surveillance and control programs arc generally based on results of samples taken from the fattening pigs and intervention measures are limited to the fattening unit. To evaluate the role of the sows in the assignment as Salmonella risk herd we compared the serological status from sows at risk herds to the status of sows at non-risk farms. From this study it is clear that the role of the sows and their serological Salmonella status is a potential influencing factor for the assignment of Salmonella risk farms in the Belgian Salmonella control program, which is principally based on sampling of fattening pigs. More insight in the role of the sow as a reservoir for Salmonella infections might help to define important intervention measures at pre-harvest stage.</p

Bacteriological prevalence in finishing pig farms assigned as Salmonella risk farms by serological screening

The Belgian Federal Agency for the Safety of the Food Chain (FASFC) installed a National Salmonella surveillance and control program in pigs, the Salmonella Action Plan (SAP), which became compulsory by means of a Royal act in July 2007. Assignment as Salmonella risk farm is based on serological analysis of blood samples collected from the fattening pigs. The knowledge of prevailing serovars of Salmonella by bacteriological methods is essential to develop and/or evaluate the serological method. In 57% of all the assigned farms, based on serological screening (~ mean SIP-ratio's), there is 'firm evidence' by bacteriological isolation. This suggests that a sufficient correlation is achieved at herd level in the first stage of the Salmonella Action Plan.</p

Bluetongue surveillance system in Belgium: a stochastic evaluation of its risk-based approach effectiveness.

&lt;p&gt;&lt;b&gt;BACKGROUND: &lt;/b&gt;The aim of this study was to assess the sensitivity of the four major bluetongue surveillance components implemented in Belgium in 2007 for farmed animals and prescribed by the European Union regulation; winter serological screening, sentinel system, passive clinical surveillance, export testing. Scenario tree methodology was used to evaluate the relative sensitivity of detection and targeted approach of each component in terms of early detection and freedom of infection substantiation. Field data collected from the previous year&#039;s outbreaks in Belgium were used to determine the risk groups to be considered.&lt;/p&gt;&lt;p&gt;&lt;b&gt;RESULTS: &lt;/b&gt;The best sensitivities at herd level, taking into account the diagnostic test sensitivity, design prevalence and the number of animals tested within a herd were obtained with the winter screening and sentinel component. The sensitivities at risk group level, taking into account the obtained herd sensitivity, effective probabilities of infection and number of herds tested were high in all components, except for the export component. Component sensitivities ranged between 0.77 and 1 for all components except for the export component with a mean value of 0.22 (0.17-0.26). In terms of early detection, the probability of detection was best using the passive clinical component or the sentinel component. Sensitivity analysis showed that the passive clinical component sensitivity was mostly affected by the diagnostic process and the number of herds sampled. The sentinel and export components sensitivity were mainly affected by the relative risk estimates whereas the winter screening component was mainly affected by the assumptions about the design prevalence.&lt;/p&gt;&lt;p&gt;&lt;b&gt;CONCLUSIONS: &lt;/b&gt;This study revealed interesting features regarding the sensitivity of detection and early detection of infection in the different surveillance components and their risk based approach as requested by the international standards.&lt;/p&gt;</p

Transmission study of Salmonella in pigs with 3 intervention strategies

In this study, the effect of 3 different intervention strategies on the transmission of Salmonella in pigs was evaluated: feed supplementation with coated calcium-butyrate salt, vaccination and acidified drinking water. Strategies were evaluated serologically and bacteriologically using an experimental in vivo seeder setup. Significantly higher antibody titers were detected in the groups with acidified drinking water and vaccination.</p