Monitoring and eradication of PED: experiences in eleven pig herds in the Netherlands

After the first signals from the US about devastating PEDv infections in 2013, Europe was extremely motivated to prevent this virus crossing the Atlantic. A baseline study in the Netherlands, conducted in the second half of 2014, showed the naïve status of the Dutch pig industry for PEDv. In November 2014, after the first case of PED was confirmed by GD Animal Health, a PED taskforce, in which the government and all involved organizations in the Dutch pig industry were represented, decided to approach this threat cooperatively.

GD veterinarians were asked to evaluate the effects of intervention strategies on 11 infected farms during 6 months after infection. This study was financed by the Dutch government and pig industry.

Five fattening herds, one nursery herd and five sow herds were selected after PEDv infection was confirmed by PCR. The route of introduction of each farm was established, to prevent new introductions. For control and eradication of PEDv, a tailor made advice, mainly based on biosecurity issues, was given. For the testing of feces an adapted commercial semi quantitative reverse transcriptase PEDv PCR was used.

Regular testing of pooled fecal samples was done to monitor the effect of interventions. In sow herds nursery piglets and replacement gilts were sampled, in fattening herds a random sampling in all age groups was performed. PEDv was considered to be successfully eradicated if three sampling rounds with at least 14 days interval, of thirty randomly taken individual fecal samples proved to be PCR negative.

After the introduction of PEDv, the virus could be detected for 4-6 weeks at room level. At farm level the virus is much longer detectable due to transmission to new susceptible animals. However, we found that intervention via strict biosecurity can effectively prevent the transfer of PEDv to naive compartments in a fattening herd. Successful intervention after PEDv introduction on sow herds was achieved by infecting all sows simultaneously, followed by strict biosecurity. Three fattening -and three sow herds were declared “unsuspicious for PEDv” within 6 months after the diagnosis of PED was confirmed. The nursery herd was repopulated after double cleaning and disinfection. One fattening herd stopped farming.

The successful strategy to prevent the transmission of PEDv requires a tailor made approach, based on strict protocols and cooperation between motivated farmers and farm contacts. Regular monitoring of fecal samples is a useful tool to monitor the herd status and can motivate the farmer to keep up a high level of biosecurity until the virus is completely eradicated.

Disclosure of Interest: None Declared.