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Research
2.
Molecular typing of field isolates from two
outbreaks of infectious bursal disease virus from
Pakistan -
M. A. Zahoor, Muhammad Abubakar, Saima Naim, Q. M.
Khan, M. J. Arshed
Vet World. 2011; 4(7): 297-300
doi: 10.5455/vetworld.2011.297-300
Abstract
A reverse transcriptase polymerase chain reaction
restriction fragment length polymorphism (RT-PCR/RFLP)
technique was used for the identification and
characterization of Pakistani field isolates of
infectious bursal disease virus (IBDV). A total of
8 bursa samples were collected from two outbreaks
during September and October 2003 from Tehsil
Sumandri, Dist. Faisalabad with 40-50% mortality
in commercially reared broiler chicken flocks
experiencing signs typical of infectious bursal
disease (IBD). Four samples were found to contain
IBDV genome by One Step RT-PCR using VP2 gene
specific primers. The assay amplified a 743 bp
fragment from 701-1444 nucleotides. RT-PCR product
was further subjected to restriction digestion
using MboI and MvaI restriction enzymes. A third
enzyme SspI was used to identify the very virulent
phenotype. The RFLP profile was found similar for
all four isolates with MvaI enzyme but different
for one isolate when digested with MboI. All three
MvaI-positive viruses were further found positive
for SspI digestion and yielded RFLP profile
similar to vvIBDV in Europe whereas one isolate
was SspI negative and had a RFLP profile similar
to classic IBDV strains. The clinical history of
high mortality and SspI restriction enzyme
positivity revealed that vvIBDV strains exist in
Pakistan.
Keywords: Infectious bursal
disease virus/ Field Isolates/ One Step RT-PCR/RFLP/
Pakistan, very virulent
