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Vesicles on the teat skin of a dairy cow

Unusual presentation:

Vesicles on the teat skin of a dairy cow.

Above: Photo sent by the client.

Time and location: October 2019, Malanda Queensland.

Case definition: Fluid-filled vesicles on cloven-hoofed animal.

Gross findings: An 11 year-old dairy cow with fluid-filled vesicles on the rear teats (about 5mm wide) noted by the owner at the afternoon milking. This cow has no oral or foot lesions. Only one cow in a herd of 300 affected. The differential diagnoses were: Vesicular Diseases (FMD, Vesicular Stomatitis etc), Bovine Papular Stomatitis, Poxvirus, Staph impetigo, Bovine Herpesvirus, and BVD. Samples submitted included:

  • bloods – EDTA, heparin and clotted
  • fluid aspirate from intact vesicles
  • fresh lesion for PCR (lid of vesicle)
  • Amies Media swab of discharge for microbial culture and sensitivity
  • fixed tissue for histopathology (entire lesions / excisional biopsy).

Laboratory findings: All major EADs were ruled out with:

  • AAHL testing negative for FMD serotypes, Vesicular Stomatitis serotypes and BHV-4
  • State vet lab (BSL) testing negative for BHV-1, BHV-2, BVD and FMD PCR.

Bacterial culture (for Staph) was not done as the Amies swab was used for the FMD PCR, and the labs do not have a molecular test that they deem suitable for poxvirus.

Animal / management / environment risk factors: The lesions were self-resolving.