Improved detection systems for TT virus reveal high prevalence in humans, non-human primates and farm animals
Improved detection systems for TT virus reveal high prevalence in humans, non-human primates and farm animals
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DOI：
10.1099/0022-1317-80-8-2115
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发表时间：
1999-08-01
影响因子：
3.8
通讯作者：
Mushahwar, IK
中科院分区：
文献类型：
--
作者：
Leary, TP;Erker, JC;Mushahwar, IK
TT病毒是一种新发现的感染人类的病毒。该病毒最初从一名患有不明原因肝炎的患者（首字母T，T）中分离出来，此后在正常和患病个体中均发现了该病毒。在本研究中，我们利用TT病毒不同基因型的基因组长度序列设计基于PCR的检测方法，使用来自病毒基因组三个独立区域的保守寡核苷酸引物。发现这三种检测方法均上级先前发表的基于PCR的检测方法。最敏感的新检测方法用于证明TT病毒的流行率在志愿献血者中至少为34.1%，在商业献血者中为39.6%，在非A-GB肝炎病例中为59.6%，在注射毒品使用者中为81.7%，在血友病患者中为95.9%。为了确定人类感染的可能来源，我们发现TT病毒序列存在于19%的鸡、20%的猪、25%的牛和30%的羊中。序列测定和系统发育分析表明，从农场动物中分离的菌株与在人类中发现的菌株在遗传上没有区别。这项研究清楚地表明，以前报道的PCR检测大大低估了TT病毒在人群中的真实流行率。由于献血者和非甲-乙型肝炎患者的感染率很高，这些结果质疑TT病毒在不明原因肝炎病例中的因果作用。此外，驯养的农场动物可能成为人类感染的来源。
TT virus is a newly described agent infecting humans. Initially isolated from a patient (initials T, T,) with unexplained hepatitis, the virus has since been found in both normal and diseased individuals. In the present study, we utilized genomic-length sequences from distinct genotypes of TT virus to design PCR-based assays using conserved oligonucleotide primers from three independent regions of the virus genome. Each of the three assays was found to be superior to the PCR-based assays previously published. The most sensitive of the new assays was utilized to demonstrate the prevalence of TT virus to be at least 34.1% in volunteer blood donors, 39.6% in commercial blood donors, 59.6% in non-A-GB hepatitis cases, 81.7% in injectable drug users and 95.9% in haemophiliacs. In an attempt to identify a possible source of human infection, we found TT virus sequences to be present in 19% of chickens, 20% of pigs, 25% of cows and 30% of sheep. Sequence determination and phylogenetic analyses demonstrated that isolates from farm animals were not genetically distinct from those found in humans. This study clearly demonstrates that previously reported PCR assays dramatically underestimate the true prevalence of TT virus within the human population. Due to the high rate of infection in both blood donors and those with non-A-GB hepatitis, these results question the causal role of TT virus in cases of unexplained hepatitis. Further, it is possible that domesticated farm animals serve as a source of human infection.