Hong Kong Reports New Strain of FMD in February

The veterinary authority sent Follow Up Report No. 1 dated 26 May to the World Organisation for Animal Health (OIE).
The report covers two outbreaks of FMD at what appear to be related pig farms on 19 February. On the first, 500 pigs were affected out of a herd of 928. There were no deaths reported, nor animals destroyed. On the other farm, all 590 pigs were affected, and one animal died.
According to the report, mainly growers (aged three to four months) and a smaller number of weaners (one to three months old) were affected. Affected animals showed various degrees of lameness and ruptured/sloughed blisters/vesicles on the skin at the top of the claws, heels and nose. Necropsy of one piglet that died suddenly showed severe diffuse myocardial necrosis consistent with foot and mouth disease virus.
Historically, the serotype prevalent in Hong Kong has been and continues to be serotype O. Regarding the last cases, the OIE/FAO Reference Laboratory, the Pirbright laboratory reported the topotype as being Cathay. However, the results that returned at the end of March from Pirbright indicated that the topotype had changed from Cathay to Southeast Asia topotype on their phylogenetic chart, which is considered as a variation in the strain and appropriate to be reported to the OIE.