5. An epidemiological link has been established to infected premises and at least one of the following conditions applies—E+W
(a)one or more animals kept on the premises are positive for antibody to the disease virus structural or non-structural proteins (and previous vaccination, residual maternal antibodies or non-specific reactions can be excluded as possible causes of seropositivity);
(b)viral antigen or viral RNA specific to one of the serotypes of the disease virus has been detected and identified in samples collected from one or more animals kept on the premises;
(c)serological evidence of active infection with disease has been established in one or more animals kept on the premises (and previous vaccination, residual maternal antibodies or non-specific reactions can be excluded as possible causes of seropositivity) by detection of seroconversion from negative to positive for antibody to the disease virus structural or non-structural proteins (where a previous seronegative status cannot reasonably be expected, carried out in paired samples collected from the same animals on two or more occasions at least 5 days apart, in the case of structural proteins, and at least 21 days apart, in the case of non-structural proteins);
(d)clinical signs consistent with disease are observed in a susceptible animal kept on the premises.