Small ruminant lentiviruses: economic and productive losses, consequences of the disease

ABSTRACT: Small ruminant lentiviruses, caprine arthritis encephalitis virus, and Maedi-Visna virus cause diseases that result in significant productive losses, mostly in dairy animals. These viruses belong to the Retroviridae family, Lentivirus genus, and constitute a heterogeneous group, which may generate implications for the diagnosis and control of small ruminant lentiviruses. Losses caused by them are associated with reproductive failure, short productive life, and decreased milk production by the infected animals. In addition, these viruses may reduce milk quality, affecting the production of dairy products such as cheese. Small ruminant lentiviruses lead to indirect losses, decreasing herd value and forcing the development of epidemiological trade barriers for animal germplasm. Control of small ruminant lentiviruses is important to promote optimal milk production and to reduce costs with medicine and technical assistance. This control may vary in caprine and ovine populations of each country, according to seroprevalence, variety of breeds, and peculiarities of the practiced management.摘要：小反刍兽慢病毒（Small ruminant lentiviruses）、山羊关节炎脑炎病毒（Caprine Arthritis Encephalitis Virus, CAEV）以及梅迪-维斯纳病毒（Maedi-Visna Virus, MVV）所引发的疫病会造成严重的生产性能损失，在乳用家畜群体中尤为突出。上述病毒隶属于逆转录病毒科（Retroviridae）慢病毒属（Lentivirus），属于具有遗传异质性的类群，这可能给小反刍兽慢病毒的诊断与防控工作带来潜在影响。该类病毒造成的损失与繁殖障碍、生产寿命缩短以及感染动物产奶量下降直接相关。此外，此类病毒还会降低乳品质，对奶酪等乳制品的生产造成不利影响。小反刍兽慢病毒还会引发间接损失，降低畜群整体价值，并迫使动物种质资源贸易设立流行病学相关贸易壁垒。防控小反刍兽慢病毒对于保障最优产奶水平、降低兽药与技术服务成本具有重要意义。不同国家的山羊与绵羊种群的防控策略或存在差异，这取决于血清流行率、品种多样性以及实际养殖管理的特有特点。