Objective To analyze the epidemiological and pathogenic characteristics of acute respiratory in-fection in Yangpu District of Shanghai,and to provide scientific basis for the prevention and treatment of re-spiratory tract infection.Methods A total of 1 062 patients diagnosed with acute respiratory infection in the hospital from June 2023 to June 2024 were selected as the research objects.The nucleic acid of 13 pathogens in nasopharyngeal swabs of patients was detected and the positive rate was calculated.The positive rate of differ-ent age groups and seasons was analyzed.Results Among 1 062 patients,716 cases were detected positive,the total positive rate was 67.42%,of which 577 cases were single infection,the positive rate was 54.33%.The top five positive pathogens were Mycoplasma pneumoniae(MP,16.48%),human coronavirus(HCOV,9.42%),human rhinovirus(HRV,7.63%),human metapneumovirus(HMPV,5.46%)and parainfluenza vi-rus(HPIV,3.39%).A total of 139 cases were infected with multiple pathogens,with a positive rate of 13.09%.MP,HRV,and HCOV were the dominant pathogens,which were prone to multiple infections.A to-tal of 139 cases were infected with multiple pathogens,with a positive rate of 13.09%.MP,HRV,and HCOV were the dominant pathogens,which were prone to multiple infections.The total positive rate of respiratory pathogens in children was 86.38%,the positive rates of single infection and multiple infection were 65.12%and 21.26%,respectively,which were significantly higher than those in other age groups(P<0.05).Among the 577 children with single infection,MP and HRV were the main pathogens in children,MP and HCOV were the main pathogens in young and middle-aged patients,and HCOV and HRV were the main pathogens in the elderly patients.The total positive rate of pathogens was the highest in winter(69.88%),and the lowest in summer(49.54%).HRV had the highest positive rate in spring,HCOV had the highest positive rate in summer,MP had the highest positive rate in autumn,and influenza virus(including influenza A virus,influen-za A/H3N2 virus,influenza B virus)had the highest positive rate in winter(P<0.05).Conclusion MP,HCOV,HRV,HMPV and HPIV are the top five pathogens of acute respiratory tract infection in Yangpu dis-trict of Shanghai.The etiological characteristics were related to age and seasonality of patients.

ObjectiveTo develop and verify a multiplex real-time RT-PCR assay for simultaneous identification of human parainfluenza virus type 1(HPIV1),type 2(HPIV2)and type 3(HPIV3).MethodsThe whole genome sequences of HPIV1,HPIV2 and HPIV3 were downloaded from the database for alignment analysis,and the conserved regions were selected. Specific primers and probes were designed for the three viruses respectively to develop a multiplex real-time RTPCR assay with human ribonuclease P(RNase P)as theinternal quality control. The method was verified for the sensitivity,specificity and precision and used to detect 192 clinical samples.ResultsAfter optimization,the multiplex real-time RTPCR reaction system was determined to be 30 μL,including 10 × NeoscriptRTase/UNG Multi mix 3 μL,5 × Neoscript RT Premix Multi Buffer 6 μL,upstream and downstream primers of HPIV1,HPIV2 and HPIV3(100 μmol/L)0. 1 μL respectively,HPIV1,HPIV2,HPIV3 probes(100 μmol/L)0. 05 μL respectively,RNase P upstream and downstream primers(50 μmol/L)0. 06 μL respectively,RNase P probe(50 μmol/L)0. 03 μL respectively,template 15 μL,and ddH2O supplemented to 30 μL. The reaction conditions were 50 ℃ 20 min,95 ℃ 3 min and 45 cycles of 95 ℃ 15 s and54 ℃ 30 s. Fluorescence signals were collected during annealing in each cycle. The minimum detection limits of HPIV1,HPIV2 and HPIV3 were all 500 copies/mL by the multiplex real-time RT-PCR assay;The method showed no cross-reaction with influenza A virus,influenza B virus,respiratory syncytial virus andnovel coronaviruses. The coefficients of variation(CVs)in intra-and inter-groups of the recombinant plasmid standard mixture with three different concentrations were all less than 3%. HPIV1,HPIV2 and HPIV3 were detected in 192 clinical samples,and the positive rates were7. 81%,0. 05% and 3. 1%,respectively.ConclusionThe multiplex real-time RT-PCR assay for detection of HPIV1,HPIV2 and HPIV3 developed in this study has good sensitivity,specificity and precision,which has a high clinical application prospect in the field of rapid diagnosis and identification of HPIV.