Pathogenicity, tissue distribution, shedding and environmental detection of two strains of IBDV following infection of chickens at 0 and 14 days of age.

We report the results of infection experiments with Australian classical strain 06/95 and variant strain 02/95 in specific pathogen free (SPF) chickens. We tested the effects of strain and age of infection on bursal atrophy, viral RNA (vRNA) load in bursa of Fabricius (bursa), spleen, thymus, caecal tonsils, faeces, litter and exhaust dust as determined by real time reverse transcriptase polymerase chain reaction (qRT-PCR). The two IBDV strains did not differ in the degree of bursal atrophy induced, lymphoid organ distribution and faecal shedding but variant strain 02/95 induced a greater antibody response to the infection than classical strain 06/95 which was associated with a more rapid decline in IBDV vRNA genome copy number (VCN) in lymphoid organs and faeces. Infection at 14 days of age induced greater bursal atrophy and higher VCN in lymphoid tissues than infection on the day of hatch, indicating true age susceptibility independent of maternal antibody (Mab) status. The direction of the association between rankings for IBDV vRNA load in bursa and relative bursal weight changed from positive at 3 and 6 days post infection (dpi) to negative at 28 dpi. Intra-tracheal administration of dust collected from chickens infected with IBDV resulted in successful transmission of IBDV. IBDV vRNA was detected successfully at high levels in the environmental litter and dust samples.
PMID: 27766900 [PubMed - as supplied by publisher]

Source: Avian Pathology - October 20, 2016 Category: Pathology Authors: Jayasundara JM, Walkden-Brown SW, Katz ME, Islam AF, Renz KG, McNally J, Hunt P Tags: Avian Pathol Source Type: research