The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

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.Arthropod-borne viral (arboviral) infections are a major public health concern, causing considerable morbidity and mortality in humans and livestock throughout the world. There are more than 100 arboviruses that cause disease in humans, including members of the Flaviviridae, Bunyaviridae, and Togaviridae families [1]. Arboviral infections produce a broad spectrum of disease, ranging from asymptomatic infection to mild febrile illness or more severe conditions, such as encephalitis or hemorrhagic fever, which may result in long-term sequelae or death [2,3]. Human and animal pathogenic arboviruses such as West Nile virus (WNV), Chikungunya virus (CHIKV), Rift Valley fever virus (RVFV) and Bluetongue virus (BTV) have emerged and caused epidemics in North America, Europe and the Arabian Peninsula [1]. Culex are important vectors of West Nile virus and other arboviruses [2,3] in North America, and consequently prediction and monitoring of their abundance are central to arboviral surveillance and contro