Objective To obtain the heavy chain variable region (VH) gene of monoclonal antibody 2F2 against Japanese encephalitis virus (JEV).Methods Total RNA was isolated with Trizol from hybridoma 2F2 cells,and cDNA of VH was amplified with reverse transcription polymerase chain reaction (RT-PCR) and sequenced.The putative VH gene was expressed in E.coli,and the expressed products was detected with enzyme linked immunosorbent assay (ELISA) to determine the activity to bind JEV.Results The VH gene was 354 bp in length which encodes 118 amino acids.Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the VH gene was successfully expressed and purified from inclusion bodies.ELISA result also demonstrated that VH gene expressed products bind purified JEV.Conclusions The VH gene of monoclonal antibody 2F2 against JEV had been cloned.

Objective To investigate the geographical distribution and seasonal fluctuations of visceral leishmaniasis vectors sandflies in Henan Province in 2023, so as to provide insights into the prevention and control of visceral leishmaniasis vectors. Methods A total of 23 counties (districts) were sampled from 18 cities of Henan Province from May to September, 2023 as sandfly surveillance sites, and sandflies were captured using human capture and light trapping methods. Following morphological identification, the changes in the sandfly density were calculated at different months and in different breeding habitats. Results A total of 406 light traps were set at sandfly surveillance sites in Henan Province from May to September, 2023, and a total of 3 137 female sandlies were captured, with an average density of 7.73 sandlies/(light·night). A total of 1 494 Phlebotomus chinensis sandflies were captured, including 1 222 female sandflies, with an average density of 3.01 sandflies/(light·night), and the highest density of P. chinensis was found in Gongyi City [17.00 sandflies/(light·night)]. A total of 5 544 sandflies were captured using the human capture method, including 230 P. chinensis, and the density of P. chinensis appeared a unimodal distribution, with a peak in early July [5.81 sandflies/(light·night)]. Among different breeding habitats, the highest P. chinensis density was detected in pigpens [4.50 sandflies/(light·night)]. Conclusions P. chinensis was predominantly distributed in hilly areas of northern and central-western Henan Province in 2023, and the sandfly density appeared a unimodal distribution. Intensified monitoring of visceral leishmaniasis vectors is recommended.