Andreadis Theodore G, Armstrong Philip M, Bajwa Waheed I
Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT 06511, USA.
J Am Mosq Control Assoc. 2010 Sep;26(3):257-64. doi: 10.2987/10-6004.1.
A 3-year study was undertaken to examine the parity status, survival, and prevalence of West Nile virus (WNV) in overwintering populations of Culex pipiens pipiens collected from a hibernaculum located in a WNV endemic region in New York City. Nearly 6,000 females were collected from December through April. Parity rates were highest among females collected in December and January, ranging from 12.3% to 21.9%, depending on the year. In each year of the study, the proportion of parous females declined significantly during the course of the winter; the percentage of parous females found in April ranged from 0.9% to 10%. Results provide unequivocal evidence that parous Cx. p. pipiens females from this region of the northeastern US enter hibernacula in the fall in comparatively high proportions not previously recognized for this species, and while these females experience significant mortality during the winter, some survived to April to emerge in the spring. The absence of any detectible blood remnants in overwintering females reaffirms that blood feeding does not occur among diapausing females during the winter. The possibility that a portion of the diapausing population may be autogenous as a result of hybridization with sympatric belowground populations of Cx. p. pipiens "form molestus" is discussed. A single isolation of WNV was obtained in Vero cell culture from a pool of 50 females collected on January 11, 2007, representing an infection prevalence of 0.07% in the overwintering population in 2007 (n = 1,370 mosquitoes, 33 pools). No isolations of WNV were made from mosquitoes collected in 2008 (n = 1,870 mosquitoes, 190 pools) or 2009 (n = 1,767 mosquitoes, 184 pools). Findings provide further evidence for local overwintering of WNV in diapausing Cx. p. pipiens, albeit at very low rates, consistent with the paucity of WNV-positive mosquitoes detected in June and early July despite the emergence of females from hibernacula in early May in this region.
开展了一项为期3年的研究，以调查从纽约市西尼罗河病毒（WNV）流行地区的一个越冬场所收集的尖音库蚊淡色库蚊越冬种群的胎次状况、存活率和WNV流行情况。从12月至4月收集了近6000只雌蚊。12月和1月收集的雌蚊胎次率最高，根据年份不同，在12.3%至21.9%之间。在研究的每一年中，经产雌蚊的比例在冬季过程中显著下降；4月发现的经产雌蚊百分比在0.9%至10%之间。结果提供了明确的证据，表明来自美国东北部该地区的经产尖音库蚊淡色库蚊雌蚊在秋季以相对较高的比例进入越冬场所，这一比例此前未被该物种所认识到，虽然这些雌蚊在冬季经历了显著的死亡率，但仍有一些存活到4月并在春季羽化。越冬雌蚊中没有任何可检测到的血液残留，再次证实滞育雌蚊在冬季不进行吸血。讨论了一部分滞育种群可能由于与同域的尖音库蚊“骚扰型”地下种群杂交而成为自体繁殖的可能性。2007年1月11日从50只雌蚊的一组样本中在Vero细胞培养物中单次分离出WNV，代表2007年越冬种群中的感染率为0.07%（n = 1370只蚊子，33组）。2008年（n = 1870只蚊子，190组）或2009年（n = 1767只蚊子，184组）收集的蚊子中未分离出WNV。研究结果为WNV在滞育的尖音库蚊淡色库蚊中进行本地越冬提供了进一步的证据，尽管发生率很低，这与该地区5月初雌蚊从越冬场所羽化后，6月和7月初检测到的WNV阳性蚊子数量稀少相一致。
