Cross-sectional study of the association between pathological conditions and myxoma-virus seroprevalence in intensive rabbit farms in Europe

Myxomatosis is a major viral disease of the European rabbit (Oryctolagus cu niculus). Two forms of the disease (nodular and amyxomatous) exist. The cli nical diagnosis of the nodular form is easily performed on the basis of typ ical skin lesions whereas that of amyxomatous forms must be based on virus isolation or detection of specific antibodies to myxoma virus (MV). The ser oprevalence of MV was studied between March 1998 and February 1999 in 16 fa rms from three European countries considered free of myxomatosis on the bas is: of the absence of typical clinical signs. MV antibodies were detected b y enzyme-linked immunosorbent assay (ELISA) (sensitivity 100%, specificity 90%) in all 16 farms: the seroprevalences corrected for test inaccuracy (95 % confidence interval) were 55 +/- 7.7% and 37 +/- 6.1% for does and broile rs, respectively. The association between herd sizes, types of rabbitries, and presence of recurrent respiratory or digestive troubles and seroprevale nce of MV antibodies was tested in logistic multiple regressions. In all mo dels, the seroprevalence of MV antibodies was significantly higher in herds (does and broilers) with recurrent respiratory or digestive troubles than in herds without these problems. The seroprevalence was also higher in herd s (does and broilers) where animals were housed totally or partially in out doors rabbitries than in totally enclosed rabbitries. The effect of herd si zes on the presence of MV antibodies was the same in does and broilers; int ermediate sizes were at lower risk than the smaller and larger ones. (C) 20 01 Elsevier Science B.V. All rights reserved.