Lundström J O, Lindström K M, Olsen B, Dufva R, Krakower D S
Department of Population Biology, Evolutionary Biology Center, Uppsala University, Sweden.
J Med Entomol. 2001 Mar;38(2):289-97. doi: 10.1603/0022-2585-38.2.289.
The Sindbis virus uses birds as vertebrate hosts in the summer amplification cycle, and the virus is transmitted by ornithophilic Culex species. Previous field and experimental studies have shown that mainly passerine birds are involved in the amplification. To delineate the pattern of Sindbis virus infections among passerines, we collected and sampled birds for blood at five study sites located in northern, central, and southern Sweden. All study sites were lowland forested wetlands and humid forests. The blood samples were assayed for Sindbis neutralizing antibodies, and we tested if the prevalence of Sindbis antibodies varied in relation to bird characteristics (i.e., species, body-mass, sex, and age), and environmental factors (i.e., year, month, and location). We found that Sindbis virus infections occurred in almost all passerine species sampled, but that the infection prevalence was unequally distributed among species. The fieldfare, the redwing, and the songthrush each had significantly higher prevalence than the average for all species. Large passerine species had higher infection prevalence than small species. The infection was less prevalent in hatching-year birds than in older birds during June and July, but not in August. Males and females had the same infection prevalence. The prevalence of Sindbis antibodies was higher in central than in southern Sweden, which coincided with a higher proportion of fieldfare-redwing-songthrush samples in the central region of the country. Thus, it is possible that regional and annual variations in the prevalence of Sindbis antibodies in Swedish passerine species depend on the number of fieldfares, redwings, and songthrushes available for feeding by vector mosquitoes.
辛德毕斯病毒在夏季扩增循环中以鸟类作为脊椎动物宿主，该病毒由嗜鸟库蚊传播。以往的野外和实验研究表明，主要是雀形目鸟类参与了病毒扩增。为了描绘辛德毕斯病毒在雀形目鸟类中的感染模式，我们在瑞典北部、中部和南部的五个研究地点收集鸟类样本并采集血液。所有研究地点均为低地森林湿地和湿润森林。对血液样本进行辛德毕斯中和抗体检测，我们测试了辛德毕斯抗体的流行率是否因鸟类特征（即物种、体重、性别和年龄）以及环境因素（即年份、月份和地点）而有所不同。我们发现，几乎所有采样的雀形目物种都发生了辛德毕斯病毒感染，但感染率在不同物种间分布不均。田鸫、欧歌鸫和画眉的感染率均显著高于所有物种的平均感染率。大型雀形目物种的感染率高于小型物种。在6月和7月，当年孵化的鸟类感染率低于年长鸟类，但8月并非如此。雄性和雌性的感染率相同。瑞典中部辛德毕斯抗体的流行率高于南部，这与该国中部地区田鸫 - 欧歌鸫 - 画眉样本所占比例较高相吻合。因此，瑞典雀形目物种中辛德毕斯抗体流行率的区域和年度变化可能取决于可供媒介蚊子叮咬取食的田鸫、欧歌鸫和画眉的数量。
