Culex pipiens (the common house mosquito or northern house mosquito) is a species of blood-feeding mosquito of the family Culicidae. It is a vector of some diseases, such as Japanese encephalitis, meningitis, and urticaria. In the US and parts of Europe, it can spread West Nile virus, and in Emilia-Romagna, Italy, it has been demonstrated to be a vector of Usutu virus.