ZIKA virus isolated from mosquitoes: a field and laboratory investigation in China, 2016

A field investigation of arboviruses was conducted in Dejiang, Guizhou Province in the summer of 2016. A total of 8,795 mosquitoes, belonging to four species of three genera, and 1,300 midges were collected. The mosquito samples were identified on site according to their morphology, and the pooled samples were ground and centrifuged in the laboratory. The supernatant was incubated with mosquito tissue culture cells (C6/36) and mammalian cells (BHK-21) for virus isolation. The results indicated that 40% (3,540/8,795) were Anopheles sinensis, 30% (2,700/8,795) were Culex pipiens quinquefasciatus, and 29% (2,530/8,795) were Armigeres subbalbeatus. Furthermore, a total of eight virus isolates were obtained, and genome sequencing revealed two Zika viruses (ZIKVs) isolated from Culex pipiens quinquefasciatus and Armigeres subbalbeatus, respectively; three Japanese encephalitis viruses (JEVs) isolated from Culex pipiens quinquefasciatus; two Banna viruses (BAVs) isolated from Culex pipiens quinquefasciatus and Anopheles sinensis, respectively; and one densovirus (DNV) isolated from Culex pipiens quinquefasciatus. The ZIKVs isolated from the Culex pipiens quinquefasciatus and Armigeres subbalbeatus mosquitoes represent the first ZIKV isolates in mainland China. This discovery presents new challenges for the prevention and control of ZIKV in China, and prompts international cooperation on this global issue.