禽流感病毒气溶胶发生、传播与传染模式

his study established an aerosol transmission model of H9N2 subtype avian influenza virus (AIV). Two trials were performed: trial 1 (T1) and trial 2 (T2). Sixty SPF chickens were randomly divided into 3 groups: inoculation group (G1), direct contact group (G2) and aerosol challenged group (G3). Two positive-negative isolators (A and B) were used to house chickens in each Trial. G1 and G2 were housed in isolator A, and G3 was housed in B. G1 were inoculated with AIV by means of dripping noses and eyes, and G2, G3 were used as direct contact or aerosol challenged group. The concentration of airborne AIV in isolator A was measured post inoculation. Oropharyngeal and cloacal swabs were collected from each chicken which were used for viral detection studies. Serum samples used to evaluate antibody response were obtained from each chicken. The results showed that AIV aerosol were detected at 3 or 2 days post inoculation (dpi) in T1 and T2, respectively, and reached a peak of 4800 PFU/m3 air and 7200 PFU/m3 air at 7 dpi. The presence of AIV in the swabs of chickens in T1G1 and T2G1 were confirmed at 3, 2 dpi, respectively. The excretion of AIV of G2 was detected at 4 dpi, and all chickens in G2 were confirmed to excrete virus. The excretion of AIV of G3 was detected at 7 dpi, and only 87% (T1G3) or 80% (T2G3) chickens in this group excreted virus. The antibody for AIV was detected at 5 or 4 dpi in T1G1 and T2G1, and reached a peak of 7.07 or 7.20 at 21 or 14 dpi, respectively. This indicated that the SPF chickens inoculated with AIV could excrete AIV through the trachea and cloacae which could pollute feed and water and transmit AIV by forming into AIV aerosol. So, in addition to be infected by direct contact, chickens in the same or adjacent henhouse could be infected AIV through aerosols even without direct contact with each other.