The Australian public is still vulnerable to emerging virulent strains ofWest Nile virus
The Australian public is still vulnerable to emerging virulent strains ofWest Nile virus
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DOI：
10.3389/fpubh.2014.00146
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发表时间：
2014-01-01
影响因子：
5.2
通讯作者：
Bielefeldt-Ohmann, Helle
中科院分区：
文献类型：
--
作者：
Prow, Natalie A.;Hewlett, Elise K.;Bielefeldt-Ohmann, Helle
蚊子传播的西尼罗河病毒（WNV）是导致人类和马病毒性脑炎爆发的原因，特别是在东欧，中东和北美最近爆发的强毒株。在澳大利亚，昆津（WNVKUN）的一种西尼罗河病毒株在北部流行，感染这种病毒通常没有症状。然而，在2011年初，在大面积洪水之后，澳大利亚东南部发生了前所未有的马WNVKUN脑炎爆发，导致1,000多例病例和10- 15%的死亡率。尽管有马感染的广泛证据，但在这次疫情期间只报告了一例轻微的人间病例。为了理解为什么在马中观察到临床疾病而在人群中没有类似的观察结果，使用来自报告马病例的地区的献血者样本进行了血清调查，以评估黄病毒暴露水平。在爆发前，人类中WNVKUN的血清阳性率较低（0.7%），在爆发期后没有显着增加（0.6%）。由于这次暴发期间不寻常的流行病学特征，还在潜在的储存宿主兔子中进行了血清调查。在2011年4月至2012年11月期间在澳大利亚各地采样的675只动物中，86只（12.7%）为WNVKUN血清阳性，2012年2月期间的患病率最高（28/145; 19.3%）。由于这是首次对澳大利亚野生兔子进行的WNVKUN血清学调查，因此还有待确定野生兔子是否能够发展足够高的病毒血症以积极参与澳大利亚的WNV传播。然而，它们可能构成虫媒病毒活动的前哨物种，这是正在进行的研究的重点。总的来说，这项研究几乎没有提供2011年爆发期间人类暴露于WNVKUN的证据，并表明澳大利亚人口仍然容易受到WNV强毒株的出现。
The mosquito-borneWest Nile virus (WNV) is responsible for outbreaks of viral encephalitis in humans and horses with particularly virulent strains causing recent outbreaks in Eastern Europe, the Middle East, and North America. InAustralia, a strain ofWNV, Kunjin (WNVKUN), is endemic in the north and infection with this virus is generally asymptomatic. However, in early 2011, following extensive flooding, an unprecedented outbreak ofWNVKUN encephalitis in horses occurred in South-Eastern Australia, resulting in more than 1,000 cases and a mortality of 10-15%. Despite widespread evidence of equine infections, there was only a single mild human case reported during this outbreak. To understand why clinical disease was seen in horses without similar observations in the human population, a serosurvey was conducted using blood donor samples from areas where equine cases were reported to assess level of flavivirus exposure. The seroprevalence to WNVKUN in humans was low before the outbreak (0.7%), and no significant increase was demonstrated after the outbreak period (0.6%). Due to unusual epidemiological features during this outbreak, a serosurvey was also conducted in rabbits, a potential reservoir host. Out of 675 animals, sampled across Australia between April 2011 and November 2012, 86 (12.7%) were seropositive for WNVKUN, with the highest prevalence during February of 2012 (28/145; 19.3%). As this is the first serological survey for WNVKUN in Australian feral rabbits, it remains to be determined whether wild rabbits are able to develop a high enough viremia to actively participate inWNVtransmission inAustralia. However, they may constitute a sentinel species for arbovirus activity, and this is the focus of on-going studies. Collectively, this study provides little evidence of human exposure toWNVKUN during the 2011 outbreak and indicates that the Australian population remains susceptible to the emergence of virulent strains of WNV.