Emergence of novel strains of avian infectious bronchitis virus in Sweden.

摘要: Infectious bronchitis virus (IBV) causes avian infectious bronchitis, an important disease that produces severe economic losses in the poultry industry worldwide. Recent IBV infections Sweden have been associated with poor growth broilers, drop egg production and thin shells layers. The complete spike gene of selected isolates from cases was amplified sequenced using conventional RT-PCR. Nucleotide amino acid sequence comparisons shown recent bear 98.97% genetic similarity strains QX-like genotype. phylogenetic analysis revealed predominant nineties, which were Massachusetts type, replaced by D388/QX-like strains, however evolutionary link could not be established. homology between two genotypes 79 81%. Remarkably, a strong positive selection pressure determined, mostly involving S1 subunit S gene. This selective resulted recombination events, insertions deletions Two new generated found nucleotide diverging 1.7-2.4% branch, indicating emergence lineage. study demonstrates constant evolution might relation to increased farming, trade vaccine pressure. findings underscore importance continuous monitoring control spread infections, as well timely adjust diagnostic methods, molecular epidemiological studies, development use vaccines are adapted changing scenario.