Serological survey of Great Britain for warbles, winter 1991-2
Sinclair, I.J.; Tarry, D.W.
Veterinary Record 132(24): 613
1993
ISSN/ISBN: 0042-4900 PMID: 8337811 Document Number: 412318
From October 1991 to April 1992, 226 242 cattle from 10 087 English and Welsh farms and 88 451 from 1957 Scottish farms were tested for the presence of antibodies to Hypoderma bovis. Four positive samples, 3 from a farm in Cumbria and 1 from a farm in Yorkshire were detected all in early February. Both farms were in typical hill-farm habitats. All 20 cows in the Cumbrian herd, which had been treated with ivermectin in November 1991, were resampled in early April when they were all serologically negative. During the survey 127 samples were not clearly negative in the first test (using 2 serum dilutions/test) and were retested using 8 doubling dilutions from 1/40 and a warble fly test kit. Comparison with retests in earlier surveys showed no statistical difference between groups of samples from the same region suggesting that there is no reason to believe that there are more animals which show some reaction in the test in counties which have had a warble fly problem in the recent past than in countries which have been warble-free for some time.