Department of Virology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
J Med Virol. 2013 May;85(5):823-7. doi: 10.1002/jmv.23529. Epub 2013 Feb 13.
Hepatitis E virus (HEV) is implicated in many outbreaks of viral hepatitis in the Indian subcontinent. The conventional diagnosis of such outbreaks rests on the detection of anti-HEV IgM antibodies. However, IgM antibodies develop after 4-5 days of infection. An early-diagnostic marker is imperative for timely diagnosis of the outbreak and also initiation of control measures. This study aimed to determine the use of hepatitis E virus antigen detection as an early diagnostic marker in an outbreak in comparison to anti-HEV IgM and RT-PCR analyses. Forty samples were collected during a suspected outbreak of viral hepatitis due to HEV. A total of 36 samples were positive for one or more HEV markers. The positivity for anti-HEV IgM, HEV antigen, and RT-PCR was 91.6%, 69.4%, and 47.2% respectively. RT-PCR and HEV antigen detection gave the highest positive results (100%) in the first 3 days of illness. Positive HEV PCR declined to 54% by Days 4-7, whereas HEV antigen and IgM detection were 88% and 100%, respectively. Sequencing of representative HEV samples indicated that the strains responsible for this outbreak belonged to genotype I, subtype 1a. HEV antigen was found to be an early diagnostic marker of acute infection. HEV antigen was detected in three additional cases in the early phase (1-3 days), and they had no detectable anti-HEV IgM antibodies. These three samples were also positive for HEV RNA. After Day 7, anti-HEV IgM was the main diagnostic indicator of infection.
戊型肝炎病毒 (HEV) 与印度次大陆许多病毒性肝炎的爆发有关。此类爆发的常规诊断依赖于抗-HEV IgM 抗体的检测。然而，IgM 抗体在感染后 4-5 天产生。早期诊断标志物对于及时诊断爆发和启动控制措施至关重要。本研究旨在确定与抗-HEV IgM 和 RT-PCR 分析相比，使用 HEV 抗原检测作为早期诊断标志物的效果。在一次疑似由于 HEV 引起的病毒性肝炎爆发中收集了 40 个样本。共有 36 个样本对一个或多个 HEV 标志物呈阳性。抗-HEV IgM、HEV 抗原和 RT-PCR 的阳性率分别为 91.6%、69.4%和 47.2%。RT-PCR 和 HEV 抗原检测在发病的前 3 天内产生了最高的阳性结果（100%）。第 4-7 天，HEV PCR 的阳性率下降至 54%，而 HEV 抗原和 IgM 检测的阳性率分别为 88%和 100%。代表性 HEV 样本的测序表明，导致此次爆发的菌株属于基因型 I、亚型 1a。HEV 抗原被发现是急性感染的早期诊断标志物。在早期（1-3 天）发现了另外三个案例中的 HEV 抗原，并且它们没有检测到抗-HEV IgM 抗体。这三个样本也对 HEV RNA 呈阳性。第 7 天后，抗-HEV IgM 是感染的主要诊断指标。
