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Bovine viral diarrhea virus (BVDV) belongs to the genus Pestivirus in the Flaviviridae family that affects cattle in Argentina and worldwide, causing significant productive and\nreproductive losses. One of the main aspects in the control of this virus is the identification and removal of persistentl...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
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Universidad de Buenos Aires. Facultad de Ciencias Veterinarias
2022
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_6324 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_6324.dir/6324.PDF |
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| Sumario: | Bovine viral diarrhea virus (BVDV) belongs to the genus Pestivirus in the Flaviviridae family that affects cattle in Argentina and worldwide, causing significant productive and\nreproductive losses. One of the main aspects in the control of this virus is the identification and removal of persistently infected animals. For this purpose, diagnostic techniques with\nhigh sensitivity/specificity, fast, low-cost, and locally adapted to the epidemiological situation\nare necessary.\nA conventional reverse transcription-polymerase chain reaction (RT-PCR) assay was adapted and implemented for BVDV detection in bovine sera from herds enrolled in BVDV\ncontrol programs, and from herds with clinical cases. Additionally, the performance of virus\nisolation, antigen-capture ELISA, conventional and real-time RT-PCR was evaluated and\ncompared for BVDV detection in serum samples and in cases of abortion or neonatal mortality. The diversity and genetic evolution of the BVDV strains obtained in this, and in other national studies, were evaluated through phylogeny and phylodynamic studies.\nThe RT-PCR method presented a high analytical sensitivity for BVDV detection in individual serum samples or in pools under the epidemiological conditions of the country.\nBVDV was detected in 1% of the cattle and in 20% of the herds. Although the current\nresearch was not conceived as an epidemiological study, the obtained results are a relevant contribution to the limited knowledge of BVDV prevalence in Argentina. On the other hand, the RT-PCR method showed a good performance for BVDV identification in aborted fetuses and neonatal mortality samples, which usually present high autolysis degree and/or\nenvironmental contamination. Comparisons among diagnostic techniques showed that any of the evaluated methods can be selected for BVDV detection in individual serum samples. Regarding the application of diagnostic techniques for BVDV detection in fetal samples, it is concluded that both molecular methods were more suitable than the antigen-capture ELISA.\nMolecular techniques should be routinely incorporated for diagnostic protocols for BVDVrelated reproductive losses. The phylogenetic study confirmed the circulation of BVDV-1a, -\n1b and -2b, being BVDV-1b the most frequent subtype. The most prevalent subtypes in the\ncountry, BVDV-1a and -1b, were further characterized through phylodynamic analysis. Both\nsubtypes would have begun their genetic diversification between the 1950s and 1960s, consistent with the first clinical descriptions of the disease in the country. Although BVDV-1a\npresented a greater 5´UTR genetic diversity than BVDV-1b, the demographic curves showed long periods of constant genetic diversity in both subtypes, confirming its endemic nature.\nIn conclusion, reliable diagnostic techniques for BVDV detection are available in the\ncountry. Therefore, the choice of diagnostic techniques will depend on various factors such\nas sample type, number of samples, clinical presentation, laboratory infrastructure, and costs. The results obtained from the genetic studies contribute to the knowledge of the evolutionary history of BVDV in Argentina. Moreover, these data could be useful for the\ndesign and evaluation of epidemiological studies, diagnostic tools, and disease control\nprograms. |
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