فهرست مطالب sh. shahsavandi

Newcastle disease (ND), avian influenza (AI) and infectious bursal disease (IBD) cause severe damage to the poultry industry. Vaccination is often used to prevention or control the spread of poultry diseases. Inactivated vaccines are used to produce the uniform antibody titer, the increase antibody levels and its shelf life. In this study, the ND, AI and IBD triple inactivated vaccine was designed and prepared in laboratory scale. Then its immunization potential was evaluated in SPF chickens. To produce the triple vaccine, the ND V4, avian AI H9N2 and IBD 07IR standard strains were separately propagated in embryonated eggs. The viral suspensions were inactivated after virus titration. Different amounts of each virus were considered as a dose and introduced as a vaccine after standard control tests. The prepared vaccine was injected along with an imported vaccine to different groups of SPF chickens and HI, VN and ELISA tests were performed on serum samples. The HI titer was 7.6 for ND and 6.7 for AI. In the VN test, the neutralization index for IBD was 3.5. In the ELISA test, the antibody titer against ND was 8481, for AI 7569 and for IBD 3108. These data did not differ significantly from the results of the imported vaccine. The results showed that the developed triple inactivated vaccine provided good immunity and also had no side effects for SPF chickens.

Newcastle Disease Virus (NDV)is one of the most contagious viral diseases of poultry with rapid spread around the world. It identified by respiratory symptoms, nervous and digestive disorders, and high mortality. NDv causes significant economic losses in poultry industry throughout the world. Avian paramixovirus serotype 1(APMV-1) is a member of family paramyxoviridae, the genus Avulavirus, Newcastle disease virus belongs to APMV-1. The aim of this study to recognize and phylogenic analysis of Newcastle disease Virus isolated from poultry farms in Markazi Province by RT-PCR. In this research, recognition and phylogenic analysis was performed based on F gene of Newcastle disease virus. About 30 samples including brain, trachea, lung and spleen were obtained from suspected farms. Then, They were inoculated to 9 - 11 days age SPF embryonic eggs. After that 2-5 days, The Allantoic fluid harvested, the HA test was performed and genetically analysis using specific primer for F gene was done by RT PCR. In this study, Among the samples 13 of them was confirmed as Newcastle disease virus. Phylogeny tree was constructed for F gene using MEGA 6 software. The results showed that all isolates NDV belonged to genotype VII and subgenotype VII-j. These obtained data can use to improve the efficacy of the vaccine and disease prevention program, as well as its use for vaccine production against the Newcastle-disease causative agents.

Infectious bronchitis is an avian acute and highly contagious disease that causes heavy economic losses in poultry industry. Inactivated and live attenuated vaccines containing different virus serotypes (e.g. H-120) are widely used to control the disease. These vaccines should be periodically evaluated in the vaccinated chickens. The purpose of this study was to evaluate the serum responses following administration of Razi infectious bronchitis virus (IBV) H-120 strain vaccine and compare them with the results of the same commercial imported vaccine. In this case, a farm of broiler chickens includes two poultry house was selected. The groups of chickens in each house were administrated with one of the imported or RAZI IBV vaccines. Twenty chickens per group were bleeded at 4, 10, 20, 30 and 40 days after vaccination. The induced serum responses against IBV were evaluated in vaccinated chickens by ELISA and serum neutralization (SN) tests. In this research, no significant differences were found in ELISA antibody titer between the two groups that vaccinated with Razi H-120 vaccine and similar imported vaccine (CEVA Company) in any of the blood transfusion episodes. The results of the serum neutralization test confirmed the ELISA data. The result of this study was showed that IBV H-120 Razi vaccine, like the same imported vaccine, has potency to induce immunity in broiler flocks.

Avian influenza viruses are considered as a serious threat to human and animal health. An increase in expression of proinflammatory cytokines and type I IFN genes, as well as host cell death responses contribute to the pathogenesis of influenza infection. Hence, this study aimed to evaluate the growth dynamics of subacute avian influenza virus in human respiratory alveolar epithelium cells (A549). The A549 cell cultures were infected at MOIs 0.1 and 2.0 viral doses in the presence and absence of trypsin. The virus growth kinetics were elucidated by the plaque assay and the cell viability was determined by MTT at various times after the infection. The induction quality of programmed cell death as well as the signal transduction pathway of death were assessed by genomic DNA fragmentation and western blotting respectively. The study findings indicated that although the H9N2 virus replication did produce a marked cytopathic effect on the alveolar cells, which led to a reduction in the cell viability, the viral titers were increased in the infected cells. The virus replication of in these cells indicated repression of host defense mechanism as well as activation of cell death. The induction of apoptosis in A549 cells was correlated with the increased virus titers as well as virus replication (p< 0.05). H9N2 avian influenza virus were demonstrated to induce apoptosis in human alveolar epithelial cells via the intrinsic pathway in a dose-dependent manner.

Infectious bursal disease (IBD) is an acute contagious viral disease of birds worldwide. The causative virus induces a persistent immune suppression following destroy B lymphocytes precursors in bursal lymphoid follicles. Vaccination is the main strategy for prevention of the disease in commercial poultry industry. To produce a live vaccine against the disease, an new virus strain was isolated from the affected bursa of Fabricius. Diagnostic serological tests, histopathology and molecular examinations were done for pathotyping the isolate. The results indicated that the virus is a new strain and named IBD07IR. In case of developing live IBD vaccine, the bacteriology, purity, titration, reversion to virulence, bursa-body index, immunosupression and efficacy tests were performed on the candidate vaccine virus seed. The live vaccine was produced following propagation of the IBDV seed in SPF embryonated eggs. The proper dose of the vaccine was found by administration of SPF chicken groups. Afterward, the laboratory trial was scaled and the clinical trials were done three times with different administration routs. According to serological assays and challenge, the developed live IBD vaccine induces an adequate immunity in both SPF and commercial chickens and had no adverse effects.

The caspases are unique proteases that mediate the host cell apoptosis during viral infection. In this study, we identified the caspase cleavage motifs of H5N1 and H9N2 influenza viruses isolated during 1998-2012. Amino acid sequences of the eleven proteins encoded by the viruses as the caspase substrates downloaded from NCBI. The caspase cleavage motifs predicted at the three scanning P4P1, P4P2', and P14P10'–trained support vector machine classifier. Data showed that H5N1 and H9N2 viruses were represented the same cleavage motif pattern for some of the viral proteins substrates. The HA, NP, and NS1 of H9N2 viruses were found to possess additional cleavage motifs from 2005, when an outbreak wave of H5N1 viruses was expanded through Asia. Moreover, the cleavage motif of PB1-F2 protein was differing in both subtypes. The results indicated that the caspase activity of PB1-F2 protein may be involve in the viral pathogenicity.