MOLECULAR CHARACTERIZATION OF AVIAN INFECTIOUS BRONCHITIS VIRUS STRAINS FROM OUTBREAKS OCCURRED IN ARGENTINA DURING 2001-2008 PERIOD.

RIMONDI,A; CRAIG,M I.; VAGNOZZI, A; KONIG, G; DELAMER, M; PEREDA, A

AVIAN PATHOLOGY

Año: 2008

0307-9457

Twenty infectious bronchitis virus (IBV) isolates were recovered from broilers and layers from different outbreaks, occurred in commercial poultry flocks from different geographic regions of Argentina from 2001 to 2008. The viruses were isolated from tracheas, lungs, and cecal tonsils of birds that were showing respiratory symptoms. Further analysis based on their nucleotide and amino acidic sequences in the hypervariable region 1 and the intervening sequence including hypervariable regions 1 and 2 (HVR1/2) of the S1 gene were achieved to determine their genetic relationships among them and reference strains. Five isolates were highly related to Massachusetts or Connecticut serotype, indicating the probability of the detection and isolation of vaccine strains. The other Argentinean isolates conformed three separated clusters (A, B and C) distant from the vaccines serotypes with no correlation between the generated clusters and a geographic pattern. These observations could explain the failure of the Massachusetts serotype vaccination programs to control IBV in these flocks. In addition, the utilization of HVR1/2 and HVR1 sequences resulted in trees with similar topology but the phylogenetic relationships using HVR1/2 nucleotide sequences were better supported by higher bootstrap values. Therefore it is recommendable the utilization of HVR1/2 for phylogenetic studies.