Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Madero, México DF, México.
Parasit Vectors. 2011 May 9;4:70. doi: 10.1186/1756-3305-4-70.
Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids.
Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected.
Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.
库蚊属蚊子被认为是最重要的西尼罗河病毒（WNV）传播媒介，在美国至少有 34 种蚊子被检测到携带该病毒。在北美，库蚊属的库蚊、致倦库蚊和棕头库蚊都是 WNV 的有效传播媒介，WNV 在美国被认为是地方性流行的，在墨西哥的许多州也在马和鸟类中检测到，在新莱昂州也在人类中检测到。WNV 有可能通过各种途径传入墨西哥城，包括携带病毒的蚊子搭乘飞机、迁徙鸟类、地面交通和携带病毒的人类。关于库蚊复合体蚊子及其杂种在墨西哥城的地理分布知之甚少。库蚊属的库蚊偏好禽类宿主；致倦库蚊历来被认为偏好哺乳动物宿主；这两个物种的杂种理论上可以作为桥梁媒介，将 WNV 从禽类宿主传播给人类和其他哺乳动物宿主。为了应对 WNV 传入墨西哥城的可能性，我们确定了库蚊复合体蚊子及其杂种的身份和空间分布。
2004 年至 2005 年期间，从墨西哥城 103 个地点采集的蚊子幼虫通过形态分析鉴定为库蚊、库蚊属或摇蚊属。在库蚊属中，标本进一步鉴定为棕头库蚊或属于库蚊复合体。库蚊复合体成员通过测量雄性生殖器的背侧和腹侧臂（DV/D 比值）以及使用针对 Ace.2 基因设计的诊断引物来区分。采集到的最丰富的形式是致倦库蚊。
重要的 WNV 传播媒介物种，即库蚊属、致倦库蚊和棕头库蚊，均存在于墨西哥城。还采集并鉴定了库蚊属和致倦库蚊的杂种。这些 WNV 有效传播媒介的存在和丰度令人担忧。了解这些媒介的分布情况可以帮助改善墨西哥城的病毒监测活动和蚊子控制工作。
