Longworm-Tankmelk ELISA Validatie voor het aantonen van longworminfecties bij melkvee.

Abstract In recent years many farms experience outbreaks due to lungworm infection in dairy cows. Outbreaks are accompanied by respiratory distress, reduced production and loss in body condition as well as some deaths. This can lead to high economic losses. Therefore a good and easy to use diagnostic assay would be most welcome. For this purpose a bulk milk ELISA would be most useful. In the present study 37 farms were visited. Of these were 21 control farms and 16 were farms with a reported lungworm outbreak. On each farm up to 20 first-calving heifers and up to 20 older cows were sampled for faeces and blood. The faeces was used to detect lungworm larvae, while the blood samples were used in an ELISA based on the Ceditest®- Lelystad assay. In addition, on each farm a bulk milk sample was collected, which was also tested in an ELISA using the same antigen as in the Ceditest®- Lelystad assay. Data were used to evaluate the bulk milk ELISA as a diagnostic assay. Results showed that farms with a serious lungworm outbreak had a highly positive bulk milk ELISA. But not all farms with a high positive bulk milk ELISA also had a lungworm outbreak. Furthermore, not all lungworm infections as detected in the individual Baermanns and ELISAs were detected with the bulk milk ELISA. Interestingly, many older cows were found shedding lungworm larvae, which was to some extent unexpected in view of the re-infection syndrome. The latter indicates that there remains unresolved aspects on the infection dynamics of Dictyocaulus viviparus in adult cow-herds