The effect of staphylococcal antigen on the output of cells from the popliteal lymph node of immunized sheep

Serum samples collected from dogs routinely presented at a clinic between June 1974 and October 1980 were tested for the presence of haemagglutination inhibition (HI) titres to canine parvovirus. The first positive titre (> 1:320) was demonstrated in serum collected in October 1979. The first confirmed clinical case of canine parvovirus enteritis was diagnosed by the authors in July 1979.

In addition, between 1st December 1980 and 1st March 1981, serum samples were collected from 106 healthy dogs which were presented for canine parvovirus vaccination for the first time. Twenty-four dogs (approx. 23%) showed HI titres > 1:320 indicating probable previous canine parvovirus infection. Therefore approx. 80% of dogs in the clinic area were at risk at that time and vaccination should have protected them from infection.