Study explores 2022 vesicular disease outbreak
The outbreak in 2022 was the first time SVV was detected in UK pigs.
Researchers have collaborated to describe the spread of Seneca Valley virus (SVV) across England in 2022.
The vesicular disease had been identified for the first time in five outdoor pig farms in England between June and September 2022.
The research letter has been published as a collaboration between The Pirbright Institute and the Animal and Plant Health Agency (APHA), with support from the National Centre for Foreign Animal Disease in Canada. It is published in full in the journal Emerging Infectious Diseases.
Farm workers first suspected a disease outbreak after noting clinical signs in their sows, including lameness, reluctance to move, and lesions on their snout and feet. The condition was initially similar to notifiable vesicular disease such as foot-and-mouth disease.
However, samples collected from the sows soon tested negative for the usual notifiable diseases.
Scientists conducted further laboratory testing, which included virus isolation and RT-PCR testing. This confirmed the presence of SVV in five pig farms – a condition never before identified in UK pigs.
The clinical signs were exclusively reported in adult breeding sows, but the viral RNA was also detected in pigs without visible clinical signs. It was further identified in the pigs’ surroundings, including pen walls, feeders and equipment.
Following genomic sequencing, researchers discovered that the Seneca Valley viruses detected in England shared a common ancestor with a virus that had circulated in the United States in 2020. Since the sequences clustered into two closely related groups, it is suspected that either a single introduction preceded a spread between farms or there were multiple introductions.
Susanna Williamson, from APHA, said: “A key message to pig keepers and vets is that they must report any clinical signs of vesicular disease promptly to enable notifiable diseases to be ruled out through testing.
“Pig keepers should inspect their pigs at least once a day (while they are moving about) and be vigilant for lameness and lesions on the feet, snout or mouth. It is vital that any sign or suspicion of vesicular disease in pigs is reported immediately to APHA for official investigation to rule out notifiable disease.”
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