Objective To analyze the laboratory diagnosis results and epidemiological characteristics of imported malaria cases in Chongqing Municipality in 2015. Methods According to the Standard Operating Procedures of Malaria Diagnosis Ref-erence Laboratory Manual,all the blood samples collected from the imported malaria patients were detected by microscopy, RDT and nest PCR. Meanwhile,the epidemiological data of the malaria cases were collected from the Parasitic Diseases Informa-tion Management System and analyzed. Results Totally 31 cases of imported malaria were reported in Chonqing Municipality in 2015,among which,there were 2 vivax malaria cases(6.45%),23 falciparum malaria cases(74.19%),5 ovale malaria cas-es(16.13%),1 malariae malaria case(3.22%). For the 5 ovale cases,three of them were confirmed as Plasmodium ovale wal-likeri infection. Among all the cases,30 cases(96.77%)were from African countries,1(3.33%)was from Southeast Asia. Thir-ty patients were male,and 1 was female. All the patients were aged from 23-61 years. There was no obvious seasonality in the case distribution. Both the medians of duration from malaria attack to first visiting a doctor and from first visiting a doctor to diag-nosis were 2 days. The medical care units that the patients first visited were mainly county-level units,while those that made the diagnosis were mainly provincial level institutes. Conclusions All the malaria cases in Chongqing in 2015 are imported,no lo-cal cases have been found,which suggests that this municipality still maintain the malaria elimination state. However,the moni-toring and management of imported malaria cases as well as the training on malaria control for related medical staff still need to be strengthened.

Objective To understand the pathogen composition of viral diarrhea in Chongqing, and to provide reference for the prevention and control of viral diarrhea. Methods Real-time fluorescent RT-PCR was used to detect the nucleic acids of rotavirus, norovirus, sapovirus, astrovirus, and enteric adenovirus collected from diarrhea outpatient cases from 2018 to 2019, and the positive nucleic acid samples were sequenced. Results Among the 398 cases of diarrhea, 184 cases were detected positive, with the positive detection rate of 46.23%. Norovirus infection was the main infection, accounting for 29.40%. The G/P genotype of group A rotavirus was mainly G9P8, accounting for 90.32%. The genotype of norovirus was mainly GII.2[P16], accounting for 33.91%. The genotype of sapovirus was mainly GI.2, accounting for 55.56%. The genotype of astrovirus was HAstV-4, accounting for 100%. The genotype of enteric adenovirus was F41, accounting for 100%. The diarrhea cases were mainly distributed in the fourth quarter, with the positive detection rate of 70.42%, among which norovirus had the highest detection rate, accounting for 53.99%. Conclusion High incidence of viral diarrhea is in winter in Chongqing. The main pathogen of viral diarrhea is norovirus, and the genotypes of norovirus show diversity. It is necessary to prevent the outbreak and epidemic caused by norovirus in winter. In the future, the surveillance of viral diarrhea should be strengthened, and the viral diarrhea gene database should be improved to provide a scientific basis for epidemic prevention and control.

Objective To classify and identify the 53 strains of non-polio enterovirus (NPEV) isolated from acute flaccid paralysis (AFP) cases in Chongqing from 2013 to 2020, and to investigate the genotype distribution of the strains. Methods Commercial real-time fluorescence quantitative polymerase chain reaction (real-time PCR) reagents were used for rapid identification of the strains. The nucleotide sequences of VP1 and VP4 regions were used for genotyping. Results Fifty enteroviruses were identified, 33 (66%) in group A and 17 (34%) in group B. Group C and D enteroviruses were not found in these strains，and 3 strains could not be identified. In this study, EV-A71 was the dominant type, with 11 strains (22%), but EV-A71 strain was not isolated since 2016. The sequences of VP4 region and VP1 region were completely consistent in enterovirus grouping. Conclusion When using commercial real-time PCR reagents for enterovirus typing, the identification results of high CT values may be inaccurate. In the genotyping of enterovirus, the nucleotide sequence of VP4 region is first used for grouping, and then the nucleotide sequence of VP1 region is used for genotyping, which could simplify the experimental process. NPEV isolates from AFP cases in Chongqing showed poor genotype diversity. In order to enrich and improve the enterovirus gene database in Chongqing, it is necessary to carry out research on enterovirus transmitted by respiratory tract.

Objective To understand the epidemiological characteristics and genotype distribution of enterovirus (EV) in influenza-negative influenza-like illness (ILI) cases in Chongqing, and to provide a scientific basis for EV prevention and control. Methods Throat swab samples of influenza-negative ILI cases were collected from surveillance sites. The samples were detected for EV using real-time RT-PCR. The VP4 regions of positive samples were amplified and sequenced for genotyping. Results A total of 3 960 influenza-negative ILI samples were collected from January to December 2021, and 316 (7.98%) of them were EV-positive. EV could be detected in influenza-negative ILI cases in Chongqing all year round. The months with high EV-positive rates were January (11.60%), April (10.56%), May (11.79%), June (12.62%), and July (10.33%). There was a statistically significant difference in the detection rate of EV in ILI cases in different regions, gender, and age groups (χ²=29.647，χ²=4.192，χ²=69.176，P<0.05). A total of 213 EV-positive cases were successfully genotyped, including 17 genotypes of EV-A, EV-B, and EV-C and 5 genotypes of HRV-B. The dominant genotypes were CV-A4 (32.86%), CV-A2 (23.00%), CA-6 (12.21%), and CA-10 (11.74%). EV-D and novel EV were not identified in this study. Conclusion EV is an important pathogen in ILI cases in Chongqing. The prevalence of EV in ILI cases in Chongqing has typical regional, seasonal and population characteristics. Prevention and control should be carried out in Chongqing according to the epidemic characteristics of EV.