abdollah rahimian

Despite routine vaccination programs against Newcastle disease (ND), sporadic cases have occasionally occurred that remain a constant threat to commercial poultry. Ten isolates of Newcastle disease viruses (NDV) from infected broiler chicken cases were obtained from various locations in Fars province during 2009-2011 and genetically analyzed using reverse transcription polymerase chain reaction (RT- PCR) with primers specific to the viral fusion (F) protein- gene. The viruses were confirmed as NDV by hemagglutination inhibition assay and RT- PCR. The isolates based on the sequence and phylogenetic analyses of partial F gene were genotypically analyzed by RT PCR. In the present investigation, the pathogenicity of NDV strains was determined by internationally recognized test mean death time (MDT). Analysis based on F gene showed that characterized isolates possess three different types of protease cleavage site motifs and appear to show maximum identities with isolates in the region. The subsequent phylogenetic analysis was implemented using MEGA and the phylogenetic tree. The results of RT-PCR and MDT showed that 10 isolates were positive for NDV, (60% velogenic, 30% mesogenic and 10% lentogenic). The results of the phylogenetic analysis showed that 10 NDV isolates from Iran belong to the class II, genotype III viruses. This information is fundamental to improve the efficacy of controlling strategies and vaccine development for NDV.

Neospora caninum is one of main etiologic factors of abortion in  in cattle. The mass production of protozoa in laboratory conditions is performed based on growing in different cell lines. Since using suspension cell lines are very cost effective for mass production of biological products, this study aimed to evaluate the suspension cell culturing for production of this protozoan.

This study was experimentally performed bases on growth of N. caninum tachyzoites on Ka6 cell line (a cell line obtained from cattle infected with Theileria lestoquardi, Razi Institute, Shiraz, Iran. Next, based on MTT assay, ability of this cell culture for production of  N. caninum was compared with  Vero cell as the best current cell line for this purpose.

The results showed that N. caninum tachyzoites could enter into K6a cell lines and after replication released from the cells successfully. Replication of the tachyzoites was significant in both Vero and K6a cell lines in compare to the control.

To our knowledge, this is the first and successful report of suspension culture of N. caninum tachyzoites. Although, the rate of N. caninum proliferation on Ka6 cell line did not show any significant difference in compare to Vero cell line, since Ka6 cell line is a transformed lymphocytic cell and it is possible to grow massively this cell line as suspension bioreactors, it is preferred to Vero cell line.

Newcastle is an acute and contagious disease in poultry that has irreparable economic detriments in the poultry industry. Due to many deaths in broiler chicken flocks, it is vital to detect and characterize the viral circulation. The aim of this study was to isolation and pathotyping of Newcastle virus by RT-PCR and MDT (Mean death time) methods in broiler chickens in Fars province.

In this study 300 tracheal tissue and cloacal swab samples from 30 infected poultry farms with a high mortality and respiratory disease were collected in Fars province. The samples were inoculated in  the allantoic cavities of 9-11-day-old embryonated chicken eggs. After 72 hours incubation, the allantoic fluids were tested by hemagglutination, RT-PCR and MDT methods for the present of Newcastle virus and their pathotyping.

10 out of total samples investigated by molecular method showed a 535bp amplification band fragment and were identified as Newcastle viruses. Also, among these samples, Velogenic, Mesogenic and Lentogenic strains identified in 6, 3 and 1 sample respectively by MDT method.

Based on isolation of velogenic and mesogenic viruses in broiler chickens flocks, it is essential to continues survey vaccine strains and their effectiveness.

Influenza virus H9N2 is a low pathogenic avian influenza that its first outbreak in Iran was reported in 1998 and caused appreciable economic losses in the poultry industry. Vaccines are one of applicable approach for protect the avians from avian influenza viruses. This study aimed to evaluate a killed avian influenza vaccine (produced in Razi vaccine and serum research institute) against current isolates in Shiraz.

In this study, fifty broiler chickens were divided into 5 ten-bird groups including test and control groups. Forty broiler chickens (group 1, 2, 3 and 4) were vaccinated with the killed oil-emulsion influenza vaccine that was obtained from Razi Vaccine and Serum Research Institute. Ten chickens were used as control group (Nonvaccinated group). After two weeks both vaccinated and control chickens were inoculated with H9N2 influenza viruses that were isolated from chickens farms of Shiraz in 2010. The cloacal and tracheal swab samples were collected from chickens at 1,3,5,7,9,11 days after infection and were processed for virus isolation.

The results showed that after five days for group 1 and after seven days for groups 2, 3 and 4, virus shedding into tracheal and cloacal samples was significantly decreased. However, the shedding continued for 11 days in control group.

The results suggested that the killed oil-emulsion influenza vaccine could efficiently decrease AI replication and its shedding in the broiler chickens.

Influenza virus H9N2 Low Pathogenicity of the viruses that are causing the disease in 1999, two 1 and 4-year-old girl in Hong Kong. Although influenza A H9N2 subtype virus is considered as widely spread low pathogen in poultry, however there are a few reports of human infection by this virus. This study was conducted to evaluate if such infection in human related by Poultry Farm Industries i.e. workers of slaughter house, poultry farms, and poultry clinics in Iran has occurred or not.In this study, sera and swabs–nasal and throat- were collected from workers of slaughter houses, poultry farms, Razi institute. To prevent false positive and negative results in HI test the sera were treated by trypsin-periodate and concentrated RBC respectively. RT-PCR was accomplished seeking HA and NP genes of H9N2 subtype influenza viruses. Of 148 sera HI titers, two and 17 samples were 1/160 and 1/40 respectively for antibody against H9N2 influenza virus. The higher titers belonged to slaughter house workers. No viruses were detected in RT-PCR.The positive sera for antibody against H9N2 influenza virus showed a changing tendency of these viruses toward infecting human tracheal epithelia. However the highest titer in slaughter house worker showed the need to close contact with poultry and their feeces for infection to be occurred. It means that the virus needs more circulation in human population to be adapted as true human influenza virus.