Objective To identify the role of IL-17A during respiratory syncytial virus (RSV) in-fection in a mouse model. Methods Female wild-type C57BL/6 mice and IL-17A knockout ( IL-17A-/-) mice at the age of 6 to 8 weeks were both randomly divided into two groups:control and RSV groups. Mice in the control groups were given the supernatant of Hep-2 cell culture, while those in the RSV groups were treated with RSV A2 through intranasal administration. Leukocytes in bronchoalveolar lavage fluid ( BALF) samples were counted. Left lung tissues were stained with hematoxylin and eosin ( HE ) to evaluate his-topathological scores. Airway hyperresponsiveness ( AHR) was measured by whole-body plethysmography. The concentrations of IFN-γ were determined with ELISA. RSV titers were measured by plaque assay. To assess the effects of IL-17A on IFN-γproduction and its role in RSV infection, IL-17A-/- mice were treated with exogenous recombinant murine IFN-γ or IL-17A, while wild-type mice were given IFN-γ neutralizing antibody intervention. Results The counts of inflammatory cells and neutrophils in BALF, lung tissue his-topathological scores, AHR, IFN-γlevels and virus titers of the wild-type group were higher than those of the IL-17A-/-group after RSV infection. IFN-γlevels, inflammatory cell counts in BALF, AHR and lung tissue histopathological scores were significantly increased in RSV-infected IL-17A-/- mice after the intervention of recombinant murine IL-17A or IFN-γ. RSV titers were much higher in the recombinant murine IL-17A-trea-ted group, but not affected by the recombinant murine IFN-γ intervention. Inflammatory cell counts in BALF, AHR and lung tissue histopathological scores were significantly decreased in RSV-infected wild-type mice following IFN-γ neutralizing antibody treatment, but no significant changes were found in RSV titers. Conclusions IL-17A might be involved in the pathogenesis of pulmonary diseases during RSV infection through promoting IFN-γ production and inhibiting viral clearance in mice.

Objective: To identify the role of interferon (IFN)-γ during respiratory syncytial virus (RSV) re-infection in mice. Method: Female wild type C57BL/6 mice and IFN-γ knockout mice (IFN-γ^-/- mice) at the age of 6 to 8 weeks were randomly divided into two groups: control group and RSV group, according to random number table.Each group was further divided into primary infection group and re-infection group.There were 8 groups.Mice were sacrificed on days 5, 7, 14 to collect samples.There were 5-8 mice in each group at each time point.And experiment was repeated twice. Leukocytes in bronchoalveolar lavage fluid (BALF) were counted, left lung tissues were stained with HE and histopathological scoring (HPS) was performed.The concentrations of IFN-γ, IL-5, IL-13 were determined with ELISA.T test or single factor analysis of variance was used to compare between groups. Result: (1) Mice infected or reinfected with RSV showed pale hair, weight loss, decreased activity and anorexia.(2) IFN-γ levels significantly increased on days 5 and 7 following RSV primary infection and reinfection as compared to control groups in wild type mice ((192±44) vs.(36±8) and (531±161) vs.(23±4) pg/ml on day 5, (100±23) vs.(36±8) and (862±186) vs.(23±4) pg/ml on day 7, t=2.654, 2.513, 2.654, 3.968, all P<0.05). (3) Compared to the RSV-reinfected IFN-γ^-/- mice, RSV-reinfected wild type mice had less body weight loss ((13.6±2.6)% vs.(22.7±2.9)% on day 5, (18.0±3.1)% vs.(26.5±1.8)% on day 7, t=2.314, 2.308, both P<0.05), lower lung tissue histopathological score ((1.50±0.09) vs.(2.07±0.11) on day 5, (1.53±0.11) vs.(2.08±0.09) on day 7, (1.10±0.06) vs.(1.59±0.08) on day 14, t=3.916, 3.890, 4.837, all P<0.01), less BALF inflammatory cells count ((11.6±2.0) vs.(44.2±10.6)×10⁵/ml on day 5, (18.2±3.9) vs.(38.3±2.2)×10⁵/ml on day 7, t=2.818, 4.786, both P<0.05), and lower levels of IL-5 and IL-13 ((24±3) vs.(148±23), (23±4) vs.(169±26) pg/ml on day 5, (30±8) vs.(233±44), (20±5) vs.(182±19) pg/ml on day 7, (91±6) vs.(129±19), (62±8) vs.(132±5) pg/ml on day 14, t=5.252, 5.445, 4.517, 7.326, 3.816, 7.577, all P<0.01). Conclusion IFN-γ can alleviate airway inflammation following RSV reinfection in mice.

Objective:To investigate the application effect of flipped classroom combined with micro-lectures in the teaching of pediatric infectious diseases.Methods:A total of 199 five-year students in the class of 2019 from Department of Pediatrics of Chongqing Medical University were divided into 14 groups. Each group selected a micro-lecture theme targeting the key and difficult points of the course and produced an original micro-lecture video through flipped classroom, which was then uploaded to Chaoxing platform for evaluation by teachers and students. At the end of the course, a questionnaire survey was performed to investigate the teaching effect, and final examination score and department examination score during internship were compared between the students in the class of 2019 and those in the class of 2018. SPSS 22.0 was used to perform the t-test, the Wilcoxon rank-sum test, the chi-square test, and the Fisher's exact test. Results:A total of 14 flipped micro-lecture works were completed by the students. The questionnaire survey showed that 98.47% (193/196) of the students thought that this model was helpful to master the key and difficult points; 93.88% (184/196) of the students thought that the flipped micro-lecture works had better originality and quality than reading reports and literature reviews in the past; 94.90% (186/196) of the students were more willing to accept the mode of flipped classroom combined with micro-lectures. Compared with the students in the class of 2018, the students in the class of 2019 had significantly higher final examination score (79.32±7.53 vs. 76.06±12.01, P<0.001), theoretical score of department examination (88.68±4.87 vs. 87.15±4.09, P<0.001), and operation score of department examination (84.93±7.56 vs. 82.08±9.10, P<0.001). Conclusion:Flipped classroom combined with micro-lectures can effectively solve the key and difficult points in the teaching of pediatric infectious diseases, and it can also stimulate the interest in independent learning and help to improve learning performance among students. Therefore, it holds promise for clinical application.

Objective:To explore the effects of participatory interactive teaching in the clinical internship course of pediatric infectious diseases.Methods:217 undergraduate students of grade 2018 majoring in pediatrics were selected as the experimental group, and 208 undergraduate students of grade 2017 majoring in pediatrics were selected as the control group. The experimental group used the teaching method of BOPPPS combined with case-based learning and team-based learning, while the control group adopted the traditional teaching method. Evaluate the learning effectiveness by comparing the formative evaluation and theoretical exam scores of the two groups , and a questionnaire survey was conducted for the students in the experimental group to investigate teaching feedback. SPSS 19.0 was used to perform the t test for data analysis. Results:The experimental group had significantly better scores than the control group in final theoretical examination [(75.04±9.12) vs. (71.03±9.51), P<0.05] and formative evaluation [(81.03±6.13) vs. (70.02±10.32), P<0.05]. According to the results of the questionnaire survey on teaching satisfaction, the students were satisfied with the interactive participatory teaching method in the four aspects of improving learning interest, improving learning ability, classroom satisfaction level, and course acceptance level. Conclusions:The pragmatic teaching reform in the internship of pediatric infectious diseases is highly accepted by students and beneficial to improving students' clinical thinking ability and comprehensive quality, which is worth further application and promotion.

Objective:To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023.Methods:The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed.Results:A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M ( Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant ( P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age ( P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion:Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

Objective:To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023.Methods:The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed.Results:A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M ( Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant ( P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age ( P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion:Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.