| | | Number of deaths | | | | | Filter covered box |
|---|
Type of partition | Number of chicks | day 1 | day 2 | day 3 | day 4 | day 5 | day 6 | Toal number of deaths | Mortality | dead or infected | Infection ratio | Number of box | Number of infected box | Infection rate (%) |
|---|
(a) Mesh filter | 24 | 0 | 0 | 0 | 0 | 5 | 18 | 23 | 96% | 24 | 100% | 6 | 6 | 100 |
(b) Untreated filter | 20 | 0 | 1* | 0 | 0 | 0 | 7 | 7 | 37% | 15 | 79% | 5 | 5 | 100 |
(c) Antibody filter | 20 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0% | 0 | 0% | 5 | 0 | 0 |
Inoculated chicks | 48 | 0 | 0 | 42 | 6 | 0 | 0 | 48 | 100% | - | - | - | - | - |
- (a) polypropylene net with 3.7 mm square mesh-, or (b) untreated nonwoven fabric middle efficiency dust filter-, or (c) antibody impregnated same grade filter as (b), were attached to the three sides of the box cages (12 × 16 × 30 cm). Four male chickens weighing 80 g (10 days of age) were housed with food and water in each box cage covered with net or filter. Other chicks were intranasally inoculated with Highly Pathogenic Influenza virus A/Bogor 2/IPB/H5N1(105TCID50/bird). Three infected chicks were housed with food and water at the central area, closely surrounded by the filter boxes. Most of infected chicks at the central area died at 3 days post viral inoculation. At day 6, the surviving chicks in filter partitioned boxes were counted, and the mortality was calculated. In the histopathological and immunohistockemical analyses, the lungs of chicks were examined, and the box with at least one infected chick was scored as an infected box. * Since one chick in the untreatd filter box died in accidentally, the mortality and infection rate were calculated without this accidental case.
- The basic specification of the nonwoven fabric middle efficiency dust filter used in (b) and (c) is as follows; average thickness: 0.8 mm ± 0.1 mm, average arrestance: ≧70% according to JIS Z 8901 gravitational method, initial pressure loss: 25 Pa @LV 0.5 m/s.
