ARCHIVES OF RAZI INSTITUTE
Year:2007 | Volume:62 | Issue:2|Papers Count:10

FMD is one of the most highly contagious diseases of animals, caused by RNA virus belong to Picornaviridae family and Aphtovirus genus. A broad host range and occurrence of FMDV as seven serotypes and also intratypic antigenic variation without clear cut demarcations, which interferes with a concept of sub typing these factors make difficult conditions to diagnosis, control and eradication of disease. Therefore it is very important to characterize virus strains and monitoring the field virus to determine the relationship between field viruses and vaccine strains. The objective of this study was to characterize FMD type 0, A, virus isolated from Iran between 2005 and 2006. 13 FMD type A and 6 type 0 viruses isolated from Iran between 2005 and 2006 were used in this study. All viruses adapted to IBRS2 cells and the clarified infected cell culture supernatants were used for typing by sandwich capture ELlSA and extraction of viral RNA for RT-PCR reaction with the specific primer for each type. The PCR products were purified for sequencing. Sequence of 600 nucleotides at the 3' end of ID gene of all samples subjected to phylogenic analysis and determine the antigenic relationship ("r" Value). All type A viruses that isolated from different province of Iran, sequenced in this study, were closely related to each other and A/iran/05 virus group. The sequencing results of type 0 isolated from Iran between 2005 and 2006 showed the close genetic relationship between field isolates and the Iranian vaccine strain. The result of average "r" Value detected by two dimensional virus neutralization test, for type A87JR was 0.46 (46%), type A051R 0.78 (78%), type 0 Shabestar 0.81 (81%) and type 0967 0.90 (90%).

Influenza A viruses possesses two virion surface glycoproteins including haemagglutinin (HA) and neuraminidase (NA). The NA plays an important role in viral replication and promotes virus release from infected cells and facilitates virus spread throughout the body. To find out any genomic changes that might be occurred on NA gene of avian, influenza circulating viruses, we have genetically analyzed the neuraminidase gene of six Avian Influenza (AI) viruses H9N2 subtype isolated from different parts of Iran. A comparison of deduced amino acid sequences, showed some amino acid substitutions among the local AI isolates. However no insertions/deletions or shortening in the stalk region of the genes were observed. Mutation in Glu 119 as a marker for enzyme sensitivity to the antiviral drugs was not observed. Phylogenitic analysis revealed three distinct groups among the isolates of Iran, Hong Kong, and Pakistan/Japan/Saudi Arabia respectively. Based on the results, no significant mutations in NA genes of the viruses isolated during the period of the study occurred and our findings are in agreement with results of previous study of the viruses indicated a low pathogen character for the isolates on the basis of amino acid sequence of HA cleavage site and experimental infection.

In most countries, tuberculosis caused by Mycobacterium bovis is mainly a disease of cattle but can infect buffalos too. The disease can be controlled successfully by mean of a test-and-slaughter program. In Iran test and- slaughter program has started since 1971 and prevalence of bovine tuberculosis reduces from 5% to less than 0.12% in recent years. In Western Azarbaijan, North West of Iran, the prevalence of bovine tuberculosis is 0.06%. Tracing the source of infection and finding the animal reservoirs is one of the important parts of an eradication program against bovine tuberculosis and that can be achieved by differentiation of M bovis isolates. Molecular typing techniques are powerful tools for epidemiological investigations and have been extensively used for this purpose. To understand the molecular epidemiology of bovine tuberculosis in the region and possible role of buffalos, 140 specimens collected from buffaloes at abattoirs bacteriologic ally were cultured for Mycobacteria. Only one specimen was positive in culture. The isolate was identified as M tuberculosis complex by conventional biochemical tests and PCR targeting the insertion sequence IS6110. Restriction fragment length polymorphism (RFLP) analysis with polymorphic GC rich repeat (PGRS) and direct repeat (DR) probes showed that this isolate is distinct from M bovis BCG and M bovis isolates (n=10) isolated from cattle at different provinces. This is the first case of infection with M Tuberculosis complex in buffalos in Iran. The role of buffalos in transmission of infection to humans and animals needs to be investigated.

In order to develop a method for detecting and identification of Theileria annulata, the specific primers from the major merozoite-piroplasm surface antigen sequence of Theileria (Tams1) were used to detect the T. anniulataby nested-PCR technique. The assay provides a valuable tool for the identification of Theileria annulata directly from clinical samples and enables determination of the infecting species by a facile technique with high sensitivity and specificity power. The sensitivity of the PCR was determined up to 1.34 pg infected DNA, and specificity of the PCR was confirmed by DNA sequencing. The Tams1 nested-PCR assay will facilitate parasite infection follow up and might improve diagnosis and therapeutic approach of bovine tropical the ileriosis. Moreover, multiple alignment and phylogenetic analysis of Tams1 sequences of available strains/isolates showed that there is a particular restriction site in T. annulata Iran-vaccine strain could be recognized by AvaII enzyme. These findings can be used in further disease control and prevention program as wed as epidemiological studies.

Over the past several years increasing of cellulites in some regions of the country has been reported. During August and September of 2005, 4.48% of total slaughtered broilers were condemned due to cellulitis in Masjid Soleiman slaughterhouse. Four out of 98 slaughtered flocks were infected to cellulitis. The condemnation rates in infected flocks were: flock 1: 1.55%, flock 2: 0.993%, flock 3: 0.639% and flock 4: 1.66%. Bacteriologic examinations using standard biochemical techniques showed E.coli has been the most commonly isolated bacteria (90%). Sensitivity test showed diverse results which may represent different levels of various antibiotics consumption by poultry flocks.

Atlatoxins are carcinogenic metabolites produced by several strains of Aspergillus flavus group in food and feed. Cluster genes in atlatoxin biosynthesis pathway contain structural, regular and unassigned genes, nor-1 , ver-1 , and omt-1 are structural genes that coding for key enzymes and of lR is a regulatory gene that plays a key, role in the production of atlatoxin and is affecting on the structural genes and activate transcription. In this study, fourteen strains of A. flavus were examined as sample or test group. Three samples of other fungi including Aspergillus niger, Penicillium expansum and Fusarium verticillioides as negative controls and one single sample of toxigenic strain of A. flavus were studied as positive control, using nc and PCR with nor-1, ver-1, omt-1 and of lR primers. The results showed that three samples of fourteen strains of A. flavus were positive using TLC technique and totally twelve samples with the four mentioned primers using in PCR technique showed positive results. None of the other fungal strains using TLC and PCR did show any positive results. The positive control in both techniques was positive. For test sensitivity of the PCR, incubated several spore concentrations of molds accounted in above. Positive results were obtained only with extracts A. flavus, even at the lowest spore concentration applied and no DNA amplification observed with other molds even at the highest level. The interpretation of the results revealed that PCR is a rapid and sensitive method.

Hydatid cyst is an impOliant and zoonotic infection caused by cystic stage of Echinococcus granulosus. It is a major and economic problem in most areas of the world that livestock are kept such as Iran. In this study, a total of 1 1 1 buffalo's sera from Center of Buffalo Sperm Preparation (CBSP), Orumia (West Azarbayjan province, Iran, 2003) were examined for the presence of hydatidosis by using enzyme-linked immunosorbent assay (ELISA). 5mg protein per mL of antigen B from sheep hydatid cyst fluid was used in this assay. Optimum dilution for rabbit anti-bovine peroxidase conjugate (Sigma) was used 1:5000. Overall results indicated 32.4% of serum samples positive for hydatidosis. Results indicate buffalo is sensitive intermediate host for Echinococcus granulosus in this province.

In order to study the seroprevalence of pestivirus infection in small ruminants of Ahvaz at Khouzestan province of Iran, 148 sheep sera and 143 goat sera were randomly collected and tested byseroneutralization. Seroneutralization was performed by NADL strain of Bovine viral diarrhea virus genotype 1. The results indicated the overall seroprevane1ces of 46.62% in sheep and 32.871% in goats. Prevalence of pestivirus antibody showed an increase with respect to age of the animals but a significant difference was only observed between sheep <2 years and sheep >4 years. This study is the first report of pestivirus infection of goat in Iran.