[Phylogenetic study of Iranian infectious bronchitis virus isolates during 2010-2011 using glycoprotein S1 gene]

Infectious bronchitis is an acute, highly contagious, viral disease of poultry with worldwide distribution, and is continuously evolving through point mutation and recombination of their genome; subsequently the emergence of IBV variants complicates disease control. To investigate genetic characterization of new IBV variants isolated from commercial chicken flocks in Iran collected between 2009 and 2010. The partial S1 gene of the spike protein, covering a hypervariable and constant regions, was amplified and sequenced using conventional RT-PCR. Phylogenetic analysis revealed four viruses designated as Razi-HKM891, Razi-HKM892, Razi-HKM893 and Razi-HKM894. Deduced amino acid sequence comparison with other IBV genotypes, published in the GenBank database, indicated that the isolates Razi-HKM891 and Razi-HKM894 were placed into the pathogenic 793/B serotype. However, the isolates Razi-HKM892 and Razi-HKM893 were different with previously described isolates in Iran. The Razi-HKM893 is closely related to recently published isolates from countries in Middle East and likely indigenous to Iran. These findings is essential for improving the disease control strategies and thus emphasize the importance of continuous surveillance of the disease and of sharing the information to the global scientific community, which would help to fill the epidemiological gaps in the regions and to validate the robustness of diagnostic screening

[Pathogenicity indices of Newcastle disease viruses isolated from Iranian poultry flocks in Iran]

Newcastle disease [ND] is caused by serotype I of avian paramyxoviruses. The ND virus [NDV] strains are conveniently grouped as velogenic, mesogenic, lentogenic, and nonpathogenic-intestinal pathotypes. The purpose of this study was to determine the pathogenicity indices of the isolated NDVs from poultry flocks in Iran. Samples were provided from poultry flocks in different provinces of Iran and prepared for NDV isolation. From many isolated NDVs, 12 isolates belonged to 10 provinces with highly populated poultry farms which were selected for this study. A clone for each of these virus isolates was generated using limiting dilution procedure. Then, the mean death time [MDT], intracerebral pathogenicity index [ICPD, and intravenous pathogenicity index [IVPI] were determined for each virus clone and compared with those of standard virulent strains such as Hertz 33.56 and Texas GB. The results showed that the pathogenicity indices of the NDVs in the present study ranged from 41.6 - 60 hr for MDT, 1.76 - 1.91 for ICPI, and 2.68- 2.88 for IVpI indicate which the velogenic type of our viruses. The findings of this study suggested that the very virulent NDVs currently circulating in Iranian poultry flocks are close to and even more virulent than standard virulent NDVs. Isolation, identification, pathotype determination, and molecular characterization of Iranian NDVs may help authorities to make right decisions to reduce the risks posing the Iranian poultry industry

Pathogenicity and haemagglutinin gene sequence analysis of Iranian avian influenza H9N2 viruses isolated during [1998-2001]

Sixteen avian influenza [AI] H9N2 viruses were isolated from disease outbreaks in different parts of Iran during [1998-2001]. These AI isolates were used for pathogenicity, haemagglutinin [HA] gene variation and phylogenetic analysis. Results in both pathogenicity tests and HA gene cleavage site sequence detection represented a non-highly pathogenic feature for all Iranian AI isolates studied. The cleavage site motif [R-S-S-R] of all AI isolates however, indicated that they had capability of becoming highly pathogenic viruses following 2 nucleotide substitutions at this region. Based on 450 nucleotides region obtained for local isolates and those for referenced viruses available in Gene Bank database used in phylogenetic analysis, all viruses placed on 3 distinct groups, 2 for Iranian and 1 for reference viruses. Among the reference AI viruses, isolates from Pakistan, Saudi Arabia and 1 from Germany showed less differences with Iranian AI isolates. Results also revealed that the circulating viruses in neighbouring provinces have been remained with less mutation for about 2 years

efficacy of inactivated oil-emulsion H9N2 avian influenza vaccine

An experimental inactivated oil-emulsion H9N2 avian influenza vaccine was formulated with 3 parts of inactivated avian influenza antigen A/Chicken/lran/101/1998[H9N2] emulsified in 7 parts of oil adjuvant. Twelve week-old specific pathogen-free [SPF] chickens were divided into seven groups of 10 birds. Six groups were vaccinated with 1, 1/10th, 1/50th, 1/100th, 1/200th and 1/400th field dose of the experimental avian influenza vaccine [EAIV]. The last group, was injected with saline and served as the control group. The mean titer in haemagglutination inhibition [HI] test [log 2] on the vaccinated groups, 21 days post-vaccination were 6.0, 4.4, 3.83, 3.3, 3.0 and 2, respectively. Prevention of virus shedding through cloaca was used as the potency test which revealed that the protective doses 50% [PD50] of full, 1/10th and 1/50th of the field dose of the experimental vaccine were 100, 100 and 96.25%, respectively. Those groups that received <1/50th dose could not prevent virus shedding. So it can be concluded that EAI vaccine could even be entirely protective and efficient in 1/10th dose and got a desirable immunity in experimental SPF chickens