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Schmallenberg virus (SBV) emerged during summer 2011. SBV induced an unspecific syndrome in cattle and congenital signs (abortions, stillbirths and malformations) in domestic ruminants. To study the impact of SBV in Belgium, a phone survey was conducted upon September 2012. Hereto two groups of cattle farmers (A and B) and two groups of sheep farmers (C and D) were randomly selected. Farms from groups A (n = 53) and C (n = 42) received SBV-positive result at RT-PCR in the Belgian National Reference Laboratory (NRL). Farms from groups B (n = 29) and D (n = 44) never sent suspected samples to NRL for SBV analysis but were however presumed seropositive for SBV after the survey. Questionnaires related to reproduction parameters and clinical signs observed in newborn and adult animals were designed and addressed to farmers. As calculated on a basis of farmers' observations, 4% of calves in group A and 0.5% in group B were reported aborted, stillborn or deformed due to SBV in 2011-2012. The impact as observed by sheep farmers was substantially higher with 19% of lambs in group C and 11% in group D that were reported aborted, stillborn or deformed due to SBV in 2011-2012. Interestingly, abortions or stillbirths were not clear consequences of SBV outbreak in cattle farms, and the birth of a deformed animal was an essential condition to suspect SBV presence in cattle and sheep farms. This study contributes to a better knowledge of the impact of the SBV epidemic. The results suggest that SBV impacted Belgian herds mostly by the birth of deformed calves, stillborn lambs and deformed lambs. This work also demonstrates that the birth of a deformed calf or lamb was a trigger for the farmer to suspect the presence of SBV and send samples to NRL for further analyses.

Animal leptospirosis, exempt in rodents, manifests as peculiar biology where the animal can function, simultaneously or not, as a susceptible host or reservoir. In the first case, clinical symptoms are likely. In the second case, infection is subclinical and manifestations are mild or absent. Mild clinical symptoms encompass reproductive failure in production animals for host-adapted Leptospira sp. serovars. This work presents a study on Leptospira sp. infection in a mixed-species (bovine and swine) farm with documented reproductive disorders in the cattle unit. A long calving interval (above 450 days) was the hallmark observed in cows. Some cows (2/26 tested) presented a high titre of antibodies against Leptospira sp. serogroup Sejroe, but the overall within-herd prevalence was low (11.5% and 7.7% for cut-off titres of 1:30 and 1:100, respectively). The in-herd prevalence of leptospirosis in the sow unit (determined for 113/140 animals) was high when using a lowered cut-off threshold (32.7% vs. 1.8% for cut-off titre of 1:30 and 1:100, respectively). In this unit, the most prevalent serogroup was Autumnalis. The final diagnostic confirmation of Leptospira sp. maintenance within the farm was obtained through detection by PCR of Leptospira sp. DNA in an aborted swine litter. Despite the fact that a common causative infective agent was diagnosed in both species, the direct link between the two animal units was not found. Factors such as drinking from the same water source and the use of manure prepared with the swine slurry might raise suspicion of a possible cross-contamination between the two units. In conclusion, this work suggests that leptospirosis be included in the differential diagnosis of reproductive disorders and spontaneous abortions in production animals and provides data that justify the use of a lowered threshold cut-off for herd diagnosis.

A cross-sectional survey was conducted in the Belgian cattle population after the first period of infection of the emerging Schmallenberg virus. A total number of 11 635 cattle from 422 herds sampled between 2 January and 7 March 2012 were tested for the presence of Schmallenberg-specific antibodies using an ELISA kit. Between-herd seroprevalence in cattle was estimated at 99.76% (95% CI: 98.34-99.97) and within-herd seroprevalence at 86.3% (95% CI: 84.75-87.71). An Intraclass Correlation Coefficient of 0.3 (P 0.001) was found, indicating that the correlation between two animals within a herd with respect to their serological status was high. Those results corroborate the conclusion that the Schmallenberg virus was widespread in Belgium during winter 2011. Seroprevalence was shown to be statistically associated to the animal's age (P 0.0001): with 64.9% (95% CI: 61.34-68.3) estimated for the 6-12 months of age, 86.79% (95% CI: 84.43-88.85) for the 12-24 months of age and 94.4% (95% CI: 93.14-95.44) for the animals older than 24 months. Based on the results of the described serological survey, we can conclude that after the first Schmallenberg virus episode, almost every Belgian cattle has already been in contact with the virus. In consequence, the vast majority of the host animals should have developed post infection protective immunity against the virus.