Table 1.
Laboratory tests of serum and cerebrospinal specimens of suspected clinical Japanese encephalitis cases, Ningxia, China, 2018.
Table 2.
Detection of neutralizing antibodies against JEV and WNV.
Fig 1.
Cytopathic effect (CPE) of virus isolate NX1889 in Vero cells.
CPE induced by inoculating CSF specimens from NX1889 cases into Vero cells. Magnification, 200× (10×20). 4 days after inoculation, obvious CPE was observed, which presented as circular shrinkage and shedding of the cell.
Fig 2.
Spatiotemporal distribution of the 2018 JE incidence in Ningxia.
The information of JE cases demonstrated on the map were obtained from the National Notifiable Disease Reporting System (NNDRS). The spatiotemporal distribution of JE cases was analyzed using ArcGIS (v.10.0; ESRI, Redlands, CA, USA). Each point represents a case of JE; red points are cases reported (excludes the JE cases diagnosed in this study) in Ningxia in 2018, and blue points are confirmed cases diagnosed in this study. From the south to the north: GY, Guyuan City; ZW, Zhongwei City; WZ, Wuzhong City; YC, Yinchuan City; and SZS, Shizuishan City, same in Fig2(A, B, C). The shading scheme for this map is used to distinguish the five different cities of Ningxia province. Fig2A shows that 1 case was reported in July, Fig2B shows that 113 cases were reported in August, of which 67 were confirmed cases diagnosed in this study, Fig2C shows that 48 cases were reported in September.
Table 3.
Mosquito specimen collection and testing by qRT-PCR in Ningxia, 2018.
Table 4.
JEV gene detection in cerebrospinal fluid from human JE cases and mosquitoes collected from the local environment in Ningxia, 2018.
Fig 3.
Phylogenetic analyses of the E fragment of JEV from human cases and mosquitoes.
Blue indicates JE gene sequences from mosquito specimens of Ningxia in 2018. Red indicates the JEV isolate (NX1889) from cerebrospinal fluid specimens of JE cases. Fig 3A used data set of reported JEV GIb isolates[11] along with JEV GIbs from the 2018 Ningxia outbreak, including seven JEV sequences from mosquitoes and one from human; To visualize the phylogenetic relationship of JEV GIbs from Ningxia, the referenced JEV GIb isolates shown in Fig 3B were selected from Fig 3A and represent different hosts (equid, midge, human, mosquito, pig, and unknown host), different countries (China, Japan, Korea, Korea, Vietnam, Thailand, and Australia), and different times (from the 1970s to 2000s).