Seroprevalence of bovine leukemia virus in dairy cattle in Argentina: comparison of sensitivity and specificity of different detection methods
Seroprevalence of bovine leukemia virus in dairy cattle in Argentina: comparison of sensitivity and specificity of different detection methods
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DOI：
10.1016/s0378-1135(01)00420-5
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发表时间：
2001-11-26
影响因子：
3.3
通讯作者：
Carrillo, C
中科院分区：
文献类型：
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作者：
Trono, KG;Mariano, D;Carrillo, C
牛白血病病毒（BLV）是一种逆转录病毒，可引起牛的慢性感染，其病理表现有三种：无症状病程、持续性淋巴细胞增多症（PL）和淋巴肉瘤。一旦感染，牛将终生保持病毒携带者，并在感染后几周内开始显示血清学反应。根除和控制该病的基础是早期诊断和隔离带菌者。琼脂凝胶免疫扩散（AGID）试验一直是血清样品常规诊断的首选血清学试验。然而，近年来，酶联免疫吸附测定（ELISA）已取代AGED用于大规模检测。虽然阿根廷有超过6000万头牛，但尚未进行全国性的研究来确定感染的流行程度。为了估计阿根廷奶牛的BI-V感染率，沿着于1999年在我们的实验室对来自该国最大乳制品生产区的363个不同牛群的18月龄以上动物的> 10，000份血清样本中的特异性抗体进行了调查。为此，我们开发了ELISA检测血清中BLV病毒抗体。采用聚合酶链反应和南方杂交（PCR-SB）作为确认试验，对339份血清样本建立了ELISA的临界值。ELISA的敏感性和特异性分别为97.2%和97.5%，而当地官方AGID试验显示敏感性为79.7%，特异性为99.0%。为了了解奶牛群中BLV的血清阳性率以及群内感染的发生率，血清学调查基于个体血清样品。结果表明，感染个体的患病率为32.85%，而感染畜群中有一只或多只感染动物的比例为84%。这些结果表明，当单独采取时，血清阳性动物的水平为中等，但受感染农场的流行率很高，与特定地理区域的先前数据相比，在过去15年中，受感染农场的流行率明显增加，表明BLV对阿根廷的乳制品生产商构成严重的卫生问题。它们还表明，该国使用的官方AGID测试灵敏度很差。(C)2001年，爱思唯尔科学。All rights reserved.
Bovine leukemia virus (BLV) is a retrovirus that induces a chronic infection in cattle, which develop in three possible pathological forms: asymptomatic course, persistent lymphocytosis (PL) and lymphosarcoma. Once infected, cattle remain virus carriers for life and start to show a serological reaction within a few weeks after infection. Eradication and control of the disease is based on early diagnostic and segregation of the carriers. The agar gel immunodiffusion (AGID) test has been the serological test of choice for routine diagnosis of serum samples. Nevertheless, in more recent years, the enzyme-linked immunosorbent assay (ELISA) has replaced the AGED for large scale testing. Although Argentina has over 60 million cattle population, no nationwide studies have been conducted yet to determine the prevalence of the infection. To estimate the rate of BI-V infection in dairy cattle in Argentina, a survey for specific antibodies in > 10,000 serum samples from animals over 18 months old, belonging to 363 different herds from the largest dairy production areas of the country, was carried out in our laboratory, along 1999. For this purpose, we developed an ELISA to detect serum antibodies against the BLV virus. The cut-off of the ELISA was established over 339 serum samples, using polymerase chain reaction and southern blot (PCR-SB) as confirmatory test. The sensitivity and specificity of the ELISA was of 97.2 and 97.5%, respectively, while the local official AGID test showed a sensitivity of 79.7% and specificity of 99.0%. To know the seroprevalence of BLV on dairy herds, and also the incidence of the infection within the herd, the serological survey was based on individual serum samples. The results show that the prevalence of infected individuals is of 32.85%, while the percentage of infected herds, harboring one or more infected animals, is of 84%. These results indicate a medium level of seropositive animals when taken individually, but a high prevalence of infected farms, which has been notoriously increased in the last 15 years as shown when compared with previous data from particular geographic areas, indicating that BLV constitutes a serious sanitary problem for dairy producers in Argentina. They also indicate the poor sensitivity of the official AGID test used in the country. (C) 2001 Elsevier Science BY. All rights reserved.