1. SEROLOGICAL AND MOLECULAR DETECTION OF THE VERY VIRULENT IBDV IN SOME FLOCKS OF BROILER CHICKENS IN DIYALA PROVINCE, IRAQ.
- Author
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Al-Saidi, Enas T., Al-Azzawi, Amer K., and AL-Ajeeli, Karim S.
- Subjects
INFECTIOUS bursal disease virus ,POULTRY viruses ,SEROLOGY ,GENE libraries ,POLYMERASE chain reaction - Abstract
The present study was an attempt to figure out the presence of infectious bursal disease virus (IBDV) in some commercial broiler flock farms in Diyala province, Iraq by serological and molecular detection and to investigate the sequence of the detected viruses and examine the relatedness of Iraqi strains and reference strains from Genebank. A total of 360 serum samples were collected from five commercial broiler farms (groups) located all over Diyala province villages for the serological test by using indirect ELISA. Furthermore, 20 gm tissue samples of (spleen, liver, bursa) from clinical and subclinical (33) broiler flocks at the age of 2-3 weeks were collected for molecular examination by using polymerase chain reaction (PCR) for detection of IBDV. Furthermore, four tissue samples collected from bursa of Fabricius of severely IBDV infected broilers and sent to (AniCon Labor GmbH- Germany) by using (FTA- card including 4 spots) to detect the virus by real-time PCR using specific primers and probe to distinguish the pathogenic virulent strain of IBDV from non-virulent IBDV strains and made the phylogenetic tree to be more accurate in figuring out this recently detected virus in Diyala province. The results of this study show that the mean titer of anti-IBDV IgG among all five groups on the 3rd day of age as a maternally derived antibody is significantly high. After two weeks of age, the total mean titer of IgG was significantly decreased in all 5 groups compared to the MDA of all groups. The mean titer of all the 5 groups at 3rd and 4th weeks of age was significantly higher compared to the second week age group which means all the farm samples suspected to be infected with IBDV. Molecular results showed that, out of 7 samples from each flock, 5 samples (71%) were positive for IBDV. Positive samples generated a specific DNA fragment of 260 bp using specific primer pairs from a highly conserved (VP2) genome region. The molecular results by using real-time- PCR for detection of IBDV showed that 2 out of 4 samples of the bursa of Fabricius from suspected flocks were found positive for intermediated and non-virulent IBDV strains and 2 samples (50%) were very virulent (vvIBDV). The Threshold Cycle (Ct) value for RT-PCR for two isolates on bursa tissue ranged from 16.6 to 25.7. One strain was recorded in NCBI and got accession number of (Diyala/VP2/MW883071). The partial sequence of IBDV local isolates was aligned using ClustalW that was enclosed in MEGA.6 software. The local sample isolates (Diyala/VP2/MW883071) is most related to the 710- Jordan isolates with accession number (MF142560.1) and to isolate 267-Jordan (MF 142517.1) with a higher identity reach to (99.2%). [ABSTRACT FROM AUTHOR]
- Published
- 2021