The Southern House Mosquito, Culex quinquefasciatus: profile of a smart vector

Abstract

Culex quinquefasciatus is the principal vector of bancroftian filariasis and a potential vector of Dirofilaria immitis. This mosquito species is also a potential vector of several arboviruses like West Nile virus (WNV), Rift Valley fever virus, avian pox and protozoa like Plasmodium relictum that causes bird malaria. This species has the ability to transmit other nematodes like Saurofilaria sp., Oswaldofilaria sp. In the USA, it is a potential vector of St. Louis encephalitis virus (SLEV). Japanese encephalitis virus (JEV) has been isolated from this mosquito in several occasions in Asia. Furthermore, it can transmit several other arboviruses in the laboratory conditions. This article is an attempt to review the bio-ecology, medical and veterinary importance of Culex quinquefasciatus. It acts as an important “urban bridge vector” which bridges different reservoir/amplifier hosts to humans because of its encounter with different vertebrates. Culex quinquefasciatus also creates an ecological bridge between urban, periurban and rural areas owing to its presence and adaptability in diverse ecological niches. Culex quinquefasciatus emerged as a smart vector because of the adaptive fitness, ecological plasticity, invasive behaviour, host specificity and high reproductive potential along with expanded immune gene repertoire property at the genetic level. This mosquito possesses the necessary potential to initiate and facilitate the disease transmission by establishing an effective vector-host transmission cyclernfor diverse pathogens in different environments. Thus, in the changing ecological conditions this mosquito might enhance its epidemiological importance in the near future as a smart vector for those pathogens which were isolated from this mosquito species but are presently not having any public health importance.