Person: TOKER, EDA BALDAN
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TOKER
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EDA BALDAN
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Publication Molecular characterization and comparison of diagnostic methods for bovine respiratory viruses (BPIV-3, BRSV, BVBV, and BoHV-1) in field samples in northwestern Turkey(Springer, 2021-01-06) Toker, Eda Baldan; Yeşilbağ, Kadir; TOKER, EDA BALDAN; YEŞİLBAĞ, KADİR; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Viroloji Anabilim Dalı; 0000-0003-2468-3945; ABE-9974-2020; ABE-7662-2020The aim of this study was to evaluate the compatibility among virus isolation (VI), ELISA, and PCR for diagnosis of the major viral agents (BPIV-3, BRSV, BVDV, and BoHV-1) responsible for BRD in the field samples. For that purpose, a total of 193 samples (133 nasal swabs and 60 lung tissue samples) from cattle with respiratory signs in northwestern Turkey were examined. For VI, all the samples were inoculated at least 3 blind passages onto MDBK cell culture. In addition, the samples were tested by hemadsorption assay and RT-PCR for BPIV-3; nested RT-PCR for BRSV; immunoperoxidase monolayer assay, antigen-ELISA, and RT-PCR for BVDV; and antigen-ELISA and PCR for BoHV-1. The detected 1 (0.52%) BPIV-3 isolate was found to be in the genotype BPIV-3c. No BRSV isolate could be obtained, while 5 (2.59%) samples were evaluated positive in nested-RT PCR. The presence of BVDV antigen in 10 (5.18%) samples and the BVDV genome in 5 (2.59%) samples were detected, while non-cytopathogenic BVDV isolates were obtained only in 2 (1.04%) samples. The detected BVDV strains fell into the genetic clusters of BVDV-1a, -1f, and -1l. For detection of BoHV-1, although viral isolation and Ag-ELISA results were negative, presence of BoHV-1.1 genome was detected in 2 (1.04%) samples. By the results of VI, ELISA, and PCRs, 10.88% (21/193) of samples were found positive for the evaluated viruses. Depending on the obtained data, combined uses of the diagnostic methods were evaluated to be more reliable for routine diagnosis of bovine respiratory viruses.Publication Ivermectin also inhibits the replication of bovine respiratory viruses (BRSV, BPIV-3, BoHV-1, BCoV and BVDV) in vitro(Elsevier, 2021-03-05) Yeşilbağ, Kadir; Toker, Eda Baldan; Ateş, Özer; YEŞİLBAĞ, KADİR; TOKER, EDA BALDAN; Ateş, Özer; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Viroloji Anabilim Dalı.; 0000-0003-2468-3945; 0000-0001-7676-9033; ABE-9974-2020; AAH-3493-2021; GJX-0664-2022Bovine respiratory disease (BRD) complex is an important viral infection that causes huge economic losses in cattle herds worldwide. However, there is no directly effective antiviral drug application against respiratory viral pathogens; generally, the metaphylactic antibacterial drug applications are used for BRD. Ivermectin (IVM) is currently used as a broad-spectrum anti-parasitic agent both for veterinary and human medicine on some occasions. Moreover, since it is identified as an inhibitor for importin ?/?-mediated nuclear localization signal (NLS), IVM is also reported to have antiviral potential against several RNA and DNA viruses. Since therapeutic use of IVM in COVID-19 cases has recently been postulated, the potential antiviral activity of IVM against bovine respiratory viruses including BRSV, BPIV-3, BoHV-1, BCoV and BVDV are evaluated in this study. For these purposes, virus titration assay was used to evaluate titers in viral harvest from infected cells treated with noncytotoxic IVM concentrations (1, 2.5 and 5 ?M) and compared to titers from non-treated infected cells. This study indicated that IVM inhibits the replication of BCoV, BVDV, BRSV, BPIV-3 and BoHV-1 in a dose-dependent manner in vitro as well as number of extracellular infectious virions. In addition, it was demonstrated that IVM has no clear effect on the attachment and penetration steps of the replication of the studied viruses. Finally, this study shows for the first time that IVM can inhibit infection of BRD-related viral agents namely BCoV, BPIV-3, BVDV, BRSV and BoHV-1 at the concentrations of 2.5 and 5 ?M. Consequently, IVM, which is licensed for antiparasitic indications, also deserves to be evaluated as a broad-spectrum antiviral in BRD cases caused by viral pathogens.Publication Persistent BVD virus infections in offspring from imported heifers(Springer, 2019-02-01) Alpay, Gizem; Toker, Eda Baldan; Yeşilbağ, Kadir; Alpay, Gizem; TOKER, EDA BALDAN; YEŞİLBAĞ, KADİR; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Viroloji Anabilim Dalı.; 0000-0002-3411-081X; 0000-0003-2468-3945; ABE-9974-2020; AAH-3917-2021; ABE-7662-2020The aim of this study was to investigate the possible risk of bovine viral diarrhea virus transport from imported live animals. For this purpose, two different groups of animals were sampled in this study. Group 1 consisted of pregnant heifers; group 2 consisted of male beef cattle imported during 2011-2012 and 2015, respectively. Blood samples were tested for pestivirus antigen using a commercial BVDV antigen ELISA. All the pregnant heifers were negative, but 9 out of 412 offspring and 5 of the 332 male cattle were BVDV antigen positive. Virus isolation and also investigation by RT-PCR were carried out by using 14 ELISA-positive samples. At the end of three blind passages, eight non-cytopathogenic isolates were obtained by indirect immunoperoxidase monolayer assay, which were also RT-PCR positive using panpesti-virus primers. After discriminative RT-PCR, all the isolates that were identified as BVDV-1 and 5UTR-based analysis demonstrated the existence of BVDV-1b (n=4), BVDV-1f (n=2), BVDV-1l (n=1), and BVDV-1r (n=1) subgenotypes. There was no BVDV subgroup that is newly introduced into the country. However, detection of persistent infection in calves born from imported animals demonstrates the risk of BVDV virus introduction by imported animals into the receiving country. Viral strains from persistently infected animals were characterized as BVDV-1b, which is predominant subgroup in the country where animals are imported. These results highlight a possible problem for the areas where a BVDV control program is currently ongoing. Additionally, sequences obtained in this study also showed that there are two distinct branches identified in BVDV-1l.Publication In vitro antiviral activity of thymbra spicata L. extract on bovine respiratory viruses (BCoV, BPIV-3, BRSV, BVDH and BoHV-1)(Oxford Univ Press, 2021-12-21) Toker, Eda Baldan; Yeşilbağ, Kadir; TOKER, EDA BALDAN; YEŞİLBAĞ, KADİR; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Viroloji Anabilim Dalı; 0000-0003-2468-3945; ABE-9974-2020; GJX-0664-2022Aims Viral pathogens are the primary agents in bovine respiratory disease cases, and there is no direct effective antiviral drug application. Thymbra is a genus of oregano commonly found in Turkey. The primary component (34.9%) of the extract obtained from Thymbra spicata L. is the carvacrol which is used in traditional medicine. This study evaluates the potential antiviral activity and inactivation efficiency of T. spicata L. extract against bovine respiratory viruses, including BCoV, BPIV-3, BRSV, BVDV and BoHV-1. Methods and Results To evaluate its effect on viral replication, viral titres were taken from infected cells treated with non-cytotoxic T. spicata L. extract concentrations (0.75% and 1.5%, 1.32 and 2.64 mu g/ml of carvacrol as active ingredient, respectively) and compared to non-treated infected cells. The viruses were treated directly with 1.5% T. spicata L. extract, and the viral titres were evaluated at certain time points to determine the efficiency of direct inactivation. The number of infectious virions for BCoV, BPIV-3, BRSV, BVDV and BoHV-1 treated with 1.5% T. spicata L. extract were decreased by 99.44%, 100.0%, 94.38%, 99.97% and 99.87%, respectively.T. spicata L. extract strongly inhibits the replication of mentioned viruses in a dose-dependent manner in vitro. In addition, T. spicata L. extract shared direct inactivation efficiency on the mentioned viruses in a time-dependent manner. Conclusion This study shows the antiviral efficiency of T. spicata L. on BRD-related viral agents for the first time. The oregano species T. spicata and its main component, carvacrol, may have a potential for antiviral activity in the alternative treatment of respiratory viral diseases in cattle. Significance and Impact of the Study Given the similarity of replication strategies, obtained data suggest the possible efficiency of T. spicata L. on human respiratory viruses.Publication Failure in dry period vaccination strategy for bovine viral diarrhea virus(Elsevier, 2020-07-10) Toker, Eda Baldan; Aytoğu, Gizem; Kadiroğlu, Berfin; Ateş, Özer; Yeşilbağ, Kadir; TOKER, EDA BALDAN; AYTOĞU, GİZEM; KADİROĞLU, BERFİN; Ateş, Özer; YEŞİLBAĞ, KADİR; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Viroloji Anabilim Dalı.; 0000-0003-2468-3945; 0000-0001-7676-9033; AAH-3493-2021; AAH-3875-2021; ABE-7662-2020; ABE-9974-2020; ELC-2891-2022Bovine viral diarrhea is a common disease of cattle and has significant impact on animal welfare worldwide. There are fundamental approaches i.e. elimination of persistently infected animals, vaccination and biosecurity measures for effective control and eradication of BVD virus (BVDV). By this study, the presence of persistent infection with divergent BVDV subgenotype in the calves in a dairy herd having regular vaccination program was investigated. In the herd, vaccinated with a killed whole virion trivalent vaccine (composed of BVDV-1a) during the dry period of the cows, abortion cases were existed in the late autumn 2019. During herd screening by BVDV antigen-ELISA, 2 out of 300 dams were detected positive. Following, by ear notch-based BVDV antigen-ELISA, 30 calves were detected positive. Confirmation of persistent BVDV infection was performed 3 weeks later by testing with antigen-ELISA, where 8 of 9 selected newborn calves were positive for the second time. The entire antigen-ELISA positive samples were subjected to virus isolation on MDBK cell culture and identified as non-cytopathogenic pestiviruses by indirect immunoperoxidase assay. Presence of pestivirus RNA was detected in the 8 isolates by panpestivirus RT-PCR. Analysis of the 5'UTR regions revealed that BVDV-1 r circulate in the herd. Results of this study lead to questioning the efficiency of dry period vaccination strategy against BVDV. But otherwise, vaccination with BVDV-1a can be inefficient for complete protection against BVDV-1 r. Therefore, serological relationship between mentioned subgenotypes or protection by current vaccines against latest field isolates needs to be investigated before development of new BVDV vaccine candidates.