ARCHIVES OF RAZI INSTITUTE
Year:2006 | Volume:61 | Issue:2|Papers Count:10

Ten field isolates of Mycoplasma gallisepticum (MG) from different geographical areas of Iran were analyzed by random amplification of polymorphic DNA (RAPD). RAPD analysis produced reproducible banding patterns on the basis of which various distinct amplification patterns could be detected. MG isolates compared with reference strains (S6 and Mg SS) and vaccine strain (ts-11) and demonstrated distinct RAPD profiles. The results indicated genotypic diversity and heterogeneity among MG isolated from field, which can be used for epidemiological studies and for differentiation between vaccine strain, and field isolates.

Genetic typing methods of T. gondii strains have been extensively perfected in recent years. From a technical point of view, many tools usable for genetic studied on single-copy loci have been used: RFLP, PCR-RFLP, sequencing, RAPD-PCR and isoenzyme analysis. We described the cloning and sequence analysis of the gene which encodes the major surface antigen (SAG1 or P30) of T. gondii. SAG1 is the immunodominant antigen of Toxoplasma gondii tachyzoites being considered as the most promising molecule for a recombinant vaccine or such as DNA vaccine against toxoplasmosis. In the present work, first, genomic DNA of Toxoplasma gondii was extracted and used for amplifying of SAG 1 gene as a template. Then PCR product was cloned into pTZ57R/T vector and plasmid containing SAGl gene (pTSAG1) was extracted from transformed bacteria and SAGl gene cloned into pTZ57R/T was sequenced.Results showed that the P30 gene contains no introns and can extract it from genomic DNA of tachyzoite stage. Results showed also that SAG 1 gene is cloned in pTZ57R/T plasmid, forming pT-SAGl recombinant plasmid and E. coli TGl strain is the best host for pT-SAGl transformation. Sequence analysis of SAG 1 gene cloned into pTZ57R/T vector showed that SAG 1 gene sequence from a high virulent strain of T. gondii (Known as RH strain) has 100% sequence identity with P-Br strain, P strain and C strain and high homology of 98% with RH strain and ZSl strain.

The immunogenicity of ten different formulations of intranasal diphtheria and tetanus vaccines which containing different absorption enhancers, adjuvants and other excipients were determined in guinea pigs by the serum neutralization (SN) method. From these ten formulations, it was selected four formulations which gave significant immunogenicity in guinea pigs. In order to design the "final formulation" composition of these four formulations investigated properly and. final formulations designed accordingly and tested in human volunteers. The parenteral and intranasal diphtheria and tetanus toxoids (DT) vaccines were tested in two groups of human volunteers, and serological responses were estimated in both groups (The parenteral DT vaccine containing aluminum phosphates as an adjuvant). Our results showed very good serological responses (p <0.01) in both groups of human volunteers. It can be concluded that the intranasal vaccination can be a good alternate in the field of vaccination.

This study evaluated the nasopharyngeal microbial flora and antimicrobial susceptibility patterns of the one hundred and thirty Holstein calves with dairy calf pneumonia from dairy falms of Mashhad Suburb between September 2002 and August 2003. The most common micro-organisms isolated were Pasteurella multocida 80 (61.54%), Mannheimia haemolytica 41 (31.54%), Bacillus sp. 15 (11.54%), Staphylococcus sp. 3 (2.31%), Streptococcus sp. 4 (3.08%), Pseudomonas sp. 3 (2.31%), Proteus sp. 3 (2.31%) and E coli 5 (3.84%). Antimicrobial susceptibility testing was performed on all M. haemolytica and P. multocida employing the disk diffusion method (Kirby-Bauer). Each strain was tested with 10 antimicrobial agents. With 7 (17.08%), 6 (14.63%), 4 (9.75%) and 1 (2.44%) of M. haemolytica were resistant to lincomycin, gentamicin, oxytetracycline and chloramphenicol, respectively. However, resistance to penicillin, lincomycin, amoxicillin, gentamicin and oxytetracycline was observed in 10 (12.50%), 6 (7.50%), 6 (7.50%), 5 (6.25%) and 5 (6.25%) of P. multocida isolates, respectively. All M. haemolytica and P. multocida tested were found susceptible to florfenicol and cephalothin. The results show the need for local veterinarians and producers to be more responsible in the use of antibiotics in the treatment of pneumonia in calves, and growing danger of the dissemination of strains of M. haemolytica or P. multocida resistant to most antimicrobials which could complicate in the future the treatment of pneumonia in these animals.

Twelve (Experiment I) and four (Experiment II) multiparous dairy cows seronegative to pestivirus were selected and randomly assigned to either a control group which did not become infected or a treatment group in which all cows became infected following intranasal inoculation 9 days before AI. The experimental induction of infection was carried out with 2 ml of non-cytopathic pestivirus (BVD virus) suspension containing 5 log10 TCID50/ml (Experiment I) and 4.5 log10 TCID50/ml (Experiment II). In both experiments, the cows were super ovulated on day 10±2 of the cycle using the standard procedures. The cows in Experiment I were artificially inseminated at 12 and 24 h after the onset of estrus and a nonsurgical ova/embryo collection was performed 7 days after AI. In Experiment II, the cows were slaughtered on day 8 after superovulation-induced estrus and the ovaries submitted for gross and histopahological examination including immunohistochemistry: Mean (±SE) number of ovulatory sized follicles on day of AI and corpora lutea palpated on day 7 after AI were significantly (p<0.05) higher in control un-infected cows compared to that of the pestivirus infected cows (17.1±2.6 vs. 9.2±1.1 and 12.2±2.7 vs. 2.8±0.9), respectively. On histopathological examinations, the mean (±SE) number of unovulated lutenised follicles (³9 mm in diameter) present on the ovaries of the control cows on day 8 after estrus was 6.8±4.9 compared to 12.5±5.4 for the infected cows. Further, many corpora lutea in the ovaries of infected cows had a hypoplastic or atrophic wall. In conclusion, the present study demonstrated that pestivirus infection during the period of final growth of preovulatory follicles results in a disturbance in ovulation and development of corpus luteum leading to a poor superovulatory response in multiparous dairy cows.

Polycyclic aromatic hydrocarbons (PAHs) are a class of complex substances that are produced during incomplete combustion of fossil fuels. PAHs are known to be persistent pollutants which can remain in nature for years. In 1991 during the first Persian Gulf War south west part of Iran was contaminated heavily. This study was undertaken to see if the PAHs can be traceable in animal tissues many years after the incidence. One hundred of buffalos aged 12±2 years old were selected from polluted regions and to compare the results, 50 camels at same range age were also selected from a control region where expected to be contaminated by local crude oil. All the animals were scarified and fat samples were collected. Sixteen PAHs were determined by HPLC. While some of low molecular weight PAHs were not detectable, in samples from polluted region significant amount of heavy molecular weight PAHs were detected in samples of same animals fat tissues. On the other hand although most of PAHs were detected in animal samples from control region but the amount of PAHs of high molecular weight were comparatively lower in control region. Results of this study reveals that south west part of I.R. of Iran was highly contaminated by pollutants emitted during burning of Kuwait oil well  in 1991. This study may be helpful in finding the PAHs contamination and traceability of organic pollutants even after many years has passed from the incidence.

Avian influenza (AI) is one of the most economical viral diseases in Iranian poultry industry because of increased mortality and declines in egg production in affected chicken flocks. Virus isolation in embryonated SPF chicken eggs, a time consuming method, is the most common diagnostic test. In this study, virus isolation and RT-PCR for detection of avian influenza virus were evaluated by use of trachea samples collected from ten clinically affected broiler flocks. Ten percent trachea tissue suspension was inoculated to 10-day-old embryonated SPF chicken eggs. Avian influenza virus, H9N2 subtype, was confirmed in dead embryos by hemagglutination inhibition test. Simultaneously, total RNA was extracted from the trachea tissues and RT-PCR was optimized for amplification of a 488 bp DNA fragment of H9N2 subtype hemagglutinin gene. In seven of the ten flocks both the RT- PCR and virus isolation methods detected the virus. In two flocks AI virus was not detected by either method, while in a flock AI virus was identified only by RT-PCR. Newcastle disease virus was isolated in one of the flocks in which was negative by both the methods. The sensitivity and specificity rate by RT-PCR in comparison with virus isolation as gold standard test was coordinately 100% and 66%, respectively. The detection of AI by RT- PCR showed the best correlation with the virus isolation method even more sensitive than it. It is suggested that in surveillance centers where early detection of AI virus is goal, RT-PCR is a reliable method for rapid laboratory diagnosis of influenza in dead chickens because of its speed, sensitivity and specificity.

Samples of formalin fixed gastrointestinal organs of three month ostrich chicks were submitted to the department of Pathology, Razi Vaccine and Serum Research Institute. Histologically hepatitis and pancreatitis with large eosinophilic intra nuclear inclusion bodies were prominent in hepatic and pancreatic cells. These inclusions were suspected as adenovirus inclusion body hepatitis (IBH) in variety of avian species. On the epithelium of main pancreatic duct large number of cryptosporidium parasites were present.