Newcastle disease virus (strain Herts 33/56) in tissues and organs of chickens infected experimentally.

Six-week-old susceptible specific pathogen free chickens were infected intranasally with the virulent Newcastle disease virus strain Herts 33/56 and the levels of virus present in blood, faeces, breast muscle, leg muscle and a pool of heart/kidney/spleen were estimated in birds killed humanely at each day post inoculation. Highest titres were recorded at day 4 post inoculation when titres of virus were 10(6) median egg infectious doses (EID50)/g in the heart/kidney/spleen pool, 10(4.2) EID50/g in the leg muscle and 10(4) EID50/g in the breast muscle and faeces. A median oral infectious dose of Newcastle disease virus strain Herts 33/56 for 3-week-old chickens was estimated to be equivalent to 10(4) EID50.