1.The epidemiological survey shall concern:
(a)the duration of the period for which bluetongue may have been present at the holding;
(b)the possible origin of bluetongue at the holding and the identification of other holdings which have animals that may have been infected or contaminated from the same source;
(c)the presence and distribution of vectors of the disease;
(d)movements of animals from or to the holdings in question or any departure of animal carcases from those holdings.
2.A crisis unit shall be established to carry out the overall coordination of all the measures necessary for ensuring the eradication of bluetongue as soon as possible and to conduct the epidemiological survey.
General rules concerning the national crisis units and the Community crisis unit shall be laid down according to the procedure provided for in Article 20(2).