From: Bulk milk ELISA and the diagnosis of parasite infections in dairy herds: a review
 Country (region)
Number of herds
Prevalence
Reference
Belgium
1,800
19.6%
[39]
Sweden
Organic herds 113
18%
[36]
Conventional 113
9%
Germany (East Frisia)
906
12.8% Jan 07
[60]
6.9% Sept 08
6.6% Nov 08