Bovine leukemia virus (BLV), classified as a type C exogenous retrovirus in the genus Deltaretrovirus from the Retroviridae family, is the cause of Enzootic bovine leukosis (EBL), the most common neoplastic disease of cattle. Most of the BLV infected cows do not show any clinical signs and as a carrier, have the potential to transfer the virus to other animals through infected lymphocytes, lifetime. BLV infections cause significant economic losses to the livestock industry and a considerable cost is spent for its eradication and control. Hence, studies to determine the infection status at the national level is essential. Since, there is no vaccine or effective treatment against BLV infections, effective control and eradication could be possible by rapid identification of infected cows and culling or separating them. Currently ELISA is the best laboratory method in order to detect anti-BLV antibodies, especially those against p24 protein and gp51 glycoprotein. The aim of this study was to produce monoclonal antibody against p24 protein of bovine leukemia virus, in order to make it possible to develop a BLV specific competitive ELISA test in the future. For this purpose, a recombinant p24 protein which has been produced in E. coli, through gene expression, was used as the antigen. After immunizing Balb/c mice with the recombinant antigen, spleen cells of an immunized mouse were fused with SP2/0 myeloma cells using polyethylene glycol (PEG). The cells in fusion mix were suspended in HAT medium and distributed in 96-well plates. Then culture supernatants of primary clones were screened by indirect ELISA test and positive clones (2F7, 2G10 and 5C7) were selected after 2 cloning. In order to verify the immunogenicity of epitopes against which the monoclonal antibodies have been produced, the possibility for inhibition of monoclonal antibodies reaction by a polyclonal antibody against BLV (the positive control of a commercial ELISA kit) was assessed in a competitive ELISA. Based on the results, it appears that one of the monoclonal antibodies produced against p24 may be suitable for developing BLV laboratory diagnostic assays.

Influenza is an important and worldwide viral disease that causes significant economic losses in poultries. So, its rapid diagnosis is of great importance. Recently by using monoclonal and polyclonal antibodies against the nucleoprotein (NP) of Influenza virus A that were produced in Virology laboratory of Veterinary Faculty of Shahid Chamran University of Ahvaz, an in-house Antigen Capture ELISA test with high levels of sensitivity and specificity was designed to detect NP in tracheal swabs of poultries. Due to the difficulty of tracheal swabbing and also in order to facilitate sampling from sick birds, the aim of the present study was to optimize an in-house Antigen Capture-ELISA (AC-ELISA) for detection of NP in fecal samples. The optimization of the test was mainly at the fecal samples preparation step, before adding to ELISA microplate. For this purpose a virus free fecal sample was spiked with an Alantoic fluid containing H9N2 avian influenza virus and was treated with different buffers, before being tested in ELISA. According to the ELISA results, the PBS buffer containing FBS, PMSF and TRITON X-100 was the most appropriate buffer for fecal sample treatment. However, the ELISA test optimized by this buffer was not able to detect the virus in fecal samples collected from experimentally infected chickens, while the tracheal swabs of the same birds produced strong reactions in ELISA. According to this study, it seems that ELISA for detection of influenza virus in chicken fecal samples needs further optimization to improve the sensitivity of the test.

<p>Malignant Catarrhal Fever (MCF) is one the most important viral diseases of cattle and buffalo and some other animal species. MCF as fatal lymphoproliferative is known. MCF causes by two viruses: Alcelaphine Herpes Virus-1(AlHV-1) and Ovine Herpes Virus-2(OvHV-2). Wildebeest and sheep are reservior hosts for this viruses. Other herpes virus is known namely Caprine Herpes Virus-2(CpHV-2) that its host is domestic goat. The aim of this study was to investigate the OvHV-2 and CpHV-2 infection in the water buffalo population of ahvaz. Therefore, 150 whole blood samples were collected from water buffalo of the region and tested by PCR. Initially buffy coat were separated from the blood samples subjected to DNA extraction. Thereafter, the presence of OvHV-2 DNA and CpHV-2 DNA in the samples was assessed by a semi-nested PCR. The results indicated that 0.67% of the sampled water buffaloes (one case) were carrier of OvHV-2 DNA and also 0.67% of them (one case) were carrier of CpHV-2 DNA. Infection rate observed in this study was lower than previous study in 2013. Therefore probably, water buffalo can not be considered as reservoir host for OvHV-2 and CpHV-2 viruses, because this assumption is true if the viruses circulate in buffalo population independent from small ruminants. &zwnj;&zwnj;&zwnj;But, the results of our study does not prove it.</p>

Bovine leukemia virus (BLV) is a type C exogenous retrovirus belonging to the genus Deltaretrovirus, a member of the family Retroviridae. Most of BLV-infected animals remain persistently infected without clinical signs and spreading the virus as a carrier, but some of BLV infected cattle develop lymphoma (leukemia disease). BLV is an economically important virus which causes significant losses including the culling of cattle with lymphosarcoma, shortening of lifespan, decrease of production potential and restrictions on export of cattle and semen to importing countries. Due to losses caused by this virus, eradication and control programs are carrying out in some countries. Therefore, studies to determine infection status at the national level is necessary. Since the permanent presence of BLV specific antibodies is a feature of BLV infection, serological examination of cattle sera is the best method for detection of infected animals. One of commonly used serological tests is the enzyme-linked immunosorbent assay (ELISA). Most of the structural proteins of BLV are immunogenic, especially env-encoded gp51 glycoprotein and gag-encoded p24 protein. ELISA has been shown to detect both anti-p24 and anti-gp51 antibodies, in comparison to other tests. The aim of this study was molecular cloning and expression of p24 protein in a prokaryotic expression system, in order to use this recombinant protein as an antigen for developing ELISA and production of monoclonal antibody in the future. To this purpose, the p24 gene was amplified by PCR, using the blood of an infected cow as the template. Then, the amplified gene was cloned and expressed in Ecoli by using pMalc2x expression vector. Afterward, p24 recombinant protein was purified by amylose resin chromatography column. Analysis of P24 recombinant protein by dot-ELISA and Western blot, using positive and negative control sera of a commercial BLV ELISA kit confirmed the reactivity of the recombinant protein with anti-BLV antibodies. The results of this study suggest that the recombinant P24 protein potentially could be used in designing ELISA kits to detect anti-BLV antibodies or production of monoclonal antibodies.

 Peste des petits ruminants (PPR) is a primary disease in sheep and goats. Goats and sheep appear to be equally susceptible to infection by the virus, but goats exhibit a more severe clinical disease. Cattle, buffalo, camel and pigs are only subclinically infected but these animals may play an important role in the epidemiology of this virus due to the continued transmission of the virus from small ruminants to them. Therefore, knowledge of the situation of infection in these animals, especially cattle and buffalo, can provide a better understanding of PPR epidemiology in each area. For this purpose present study was undertaken to investigate the extent of infection in buffaloes slaughtered in Ahvaz abattoir. Blood samples were taken from 150 buffaloes immediately after slaughter and sera were stored at -20 ċ until be tested by virus neutralization (VN) test. Attenuated PPR virus from the live vaccine strain, cultured in VERO cell line was used for VN test. Based on VN test, 11.33% of examined buffaloes had antibodies to PPR virus. Statistical analysis showed there was no significant difference between the prevalence of infection with age and sex of buffaloes; however the rate of infection in young animal was lower than the others. Due to the fact that some of the examined buffaloes had antibodies to PPR virus; it is concluded that, PPR virus can transmit from small to large ruminants and this finding should be considered in the control and eradication of PPR. On the other hand the ability of PPR virus to infect large ruminants is a serious threat which needs more investigations.

Infectious bronchitis (IB) is one of the most important viral diseases of poultry that causes significant economic loses to chicken industry worldwide. Infectious Bronchitis Virus causes a contagious and acute respiratory disease. Some nephrotropic serotypes of IBV cause nephritis. IBV is responsible for decrease of egg production and laying abnormal eggs. IB has no treatment and the only way to protect the chicken flocks is vaccination against the virus. Immunity to IBV has most often been assessed using serological assays; like enzyme-linked immunosorbent assay (ELISA). IBV (genus Gama coronavirus, family Coronaviridae) contains a 27.6 kb single stranded positive sense RNA. The genome encodes three major structural proteins; the spike (S) glycoprotein, the integral membrane glycoprotein (M), and the 43 to 50 kDa nucleocapsid (N) phosphoprotein .
The aim of this study was to prepare recombinant nucleocapsid protein in order to develop a cheaper, safer and faster ELISA. For this purpose after RNA extraction the corresponding gene with a length of 1227 bp was amplified by RT-PCR. Then this gene cloned into expression plasmid (pMAL-C2X) and recombinant plasmid was transferred to strain Rosetta of E.coli. Expression of protein N was detected by SDS-PAGE. After purification of N protein by Amylose-resin column chromatography, the protein was used in western blot and ELISA tests to differentiate positive (contain antibody against of IBV) and negative chicken sera. The recombinant N protein successfully differentiated between both groups of serum in the two tests.
The results of this study suggested that this protein can efficiently detect antibody against IBV.