Transmission between chickens of an H7N1 Low Pathogenic Avian Influenza virus isolated during the epidemic of 1999 in Italy

The transmissibility of an H7N1 Low Pathogenic Avian Influenza (LPAI) virus isolated from a turkey flock during the large epidemic in Italy in 1999, was experimentally studied in chickens. Four group transmission experiments were performed. Infection and transmission were monitored by means of virus isolation on swab samples and antibody detection in serum samples. From the results of these groups, we estimated the mean infectious period at 7.7 (6.7–8.7) days, the transmission rate parameter at 0.49 (0.30–0.75) infections per infectious chicken per day and the basic reproduction ratio at 3.8 (1.3–6.3). These estimates can be used for the development of surveillance and control programmes of LPAI in poultry.