Estimation of Neospora caninum seroprevalence in dairy cattle from Normandy, France

An epidemiological study was conducted in Orne (France) on randomly selecte d dairy herds (42 herds including 1 924 cows and heifers, which were at lea st 15 months old). The aim was primarily to estimate the seroprevalence of Neospora caninum infection from two blood samples per cow, using an enzyme- linked immunosorbent assay (ELISA) for N. caninum (one positive result indi cating infection). The second aim was to test the association between some individual and herd factors and N. caninum seropositivity with a logistic m odel including a random term effect. The prevalence was estimated at 5.6 % (107 seropositive animals). At least 27 of the 42 herds had one seropositiv e cow or heifer. The intra-herd seroprevalence varied from 1.1 to 8 % for 1 8 positive herds (66.7 %). Dogs were present in 36 farms and 104 of the 107 seropositive animals were exposed to them. The factors associated with ind ividual seropositivity were the presence of cats (OR = 0.17; P < 0.001), do gs (OR = 4.35; P = 0.02), rabbits and/or ducks (OR = 2.10; P = 0.04), long calving periods (12 months) (OR = 0.44; P = 0.007), tethered housing (OR = 2.50; P = 0.01), somatic cell counts (200-400 x 10(3) cells/mL) (OR = 0.24; P < 0.001) and pond water supply (OR = 2.43; P = 0.04). In conclusion, the animal and intra-herd seroprevalences were low in dairy cows from Normandy , France. (C) Inra/Elsevier, Paris.