Wild ducks: natural reservoirs of influenza viruses. A proposal of programmes of ecoepidemiologic surveillance to regional level.

The wild migratory ducks are considered the natural reserves of avian influenza viruses. In fact, in such birds the influenza infection generally doesn't show clinical diseases. Besides, the virus, prevalently localized at intestinal level, is excreted in the faeces for a fairly long period. The present research, in cooperation with Istituto Nazionale della Fauna Selvatica in Ozzano Emilia (BO), has been effected on wild migratory ducks captured in the Venetia lagoon. Eighty cloacal swabs were taken and isolation methodic was in according to EEC official isolation methodology. Only one sample has shown haemagglutination up to the dilution 1:64. This sample has been sent to Laboratory of European Reference for the Avian Ortho- and Paramyxoviruses of Weybridge (CVL, Great Britain), where the identification tests are still in course for the determination of H and N antigens and of the aminoacid sequence in the site of cleavage of the haemagglutinin. In the light of obtained results, the increase of the ecoepidemiologic surveillance projects appears desirable to the wild avifauna of the Campania Region, considering the possible transmission of influenza viruses to the domestic poultry.