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Chongqing was seriously affected by hand, foot, and mouth disease (HFMD), but the relationships between daily mean temperature and the incidence of HFMD remain unclear. This study used distributed lag nonlinear model to evaluate the effect of daily mean temperature on the incidence of HFMD in children aged < 5 years in Chongqing. Daily HFMD data from 2012 to 2019 in Chongqing were retrieved from the notifiable infectious disease surveillance system. A total of 413,476 HFMD cases aged < 5 years were reported in Chongqing from 2012 to 2019. The exposure–response curve of daily mean temperature and daily HFMD cases was wavy-shaped. The relative risks (RRs) increased as daily mean temperature below 5.66 °C or above 9.43 °C, with two peaks at 16.10 °C and 26.68 °C. The RRs reached the highest when the daily mean temperature at 26.68 °C on the current day (RR = 1.20, 95% CI 1.09–1.32), followed by the daily mean temperature at 16.10 °C at lag 5 days (RR = 1.07, 95% CI 1.05–1.08). The RRs for girls and daycare children were much higher than those for boys and scattered children, respectively. Taken together, daily mean temperature has strong effect on HFMD in children aged < 5 years old in Chongqing, particularly for girls and daycare children. [ABSTRACT FROM AUTHOR]

To better understand the trends of influenza and the impact of public health and social measures (PHSMs) implemented during the coronavirus disease 2019 (COVID‐19) period in Chongqing, China. Data from the China Influenza Surveillance Information System from January 2017 to June 2022 were extracted. Epidemiological characteristics (influenza‐like illness [ILI] and ILI%) and virological characteristics (influenza positive rate and circulating (sub)types) of influenza were described and compared between the pre‐COVID‐19 period and the COVID‐19 period. Our survey showed that the implementation of PHSMs during the COVID‐19 period had a positive impact on reducing influenza transmission. However, influenza activity resurged in 2021–2022 as the PHSMs were eased. Children under 5 years old constituted the highest proportion of ILI cases. The overall influenza positive rate was 23.70%, with a higher rate observed during the pre‐COVID‐19 period (31.55%) compared to the COVID‐19 period (13.68%). Influenza virus subtypes co‐circulated and the predominant subtype varied each year, with influenza A subtypes predominated in 2018/2019, while influenza B/Victoria lineage dominated in 2020/2021. PHSMs are effective measures to mitigate the spread of influenza. The findings underscore the need for bolstering monitoring systems, advocating influenza vaccination, and implementing practical PHSMs to strengthen prevention and control measures against influenza. [ABSTRACT FROM AUTHOR]

Bacillus cereus (B. cereus) is a common cause of foodborne illness. An outbreak of acute gastrointestinal illness occurred at two middle schools in a rural region of Chongqing, China, in 2021. This study aimed to elucidate the outbreak's characteristics, identify risk factors, and determine the source of contamination. A retrospective cohort study and an environmental investigation were conducted. Vomit samples, anal swabs, and food samples were collected and tested by RT-PCR for 18 species of bacteria and viruses, including B. cereus. Positive samples of B. cereus underwent biochemical experiments and bacterial quantification. A total of 198 cases were reported in this outbreak, with an attack rate of 24.63%. The main symptoms were vomiting (100%), bellyache (83.33%), and dizziness (62.63%). The retrospective cohort study showed a significant association between the outbreak and rice noodles provided by a nearby food manufacturer (RR = 39.63, p < 0.001). B. cereus was detected in 20 vomit samples, three anal swabs, and seven rice noodles samples, with a count exceeding 103 CFU/g. These findings strongly suggested that the outbreak was linked to B. cereus-contaminated rice noodles. Enhancing food safety surveillance and promoting health measures among schools and food manufacturers in rural areas is crucial to prevent similar incidents in the future in Chongqing, China. [ABSTRACT FROM AUTHOR]

Background: The effects of multiple meteorological factors on influenza activity remain unclear in Chongqing, the largest municipality in China. We aimed to fix this gap in this study. Methods: Weekly meteorological data and influenza surveillance data in Chongqing were collected from 2012 to 2019. Distributed lag nonlinear models (DLNMs) were conducted to estimate the effects of multiple meteorological factors on influenza activity. Results: Inverted J-shaped nonlinear associations between mean temperature, absolute humidity, wind speed, sunshine and influenza activity were found. The relative risks (RRs) of influenza activity increased as weekly average mean temperature fell below 18.18°C, average absolute humidity fell below 12.66 g/m3, average wind speed fell below 1.55 m/s and average sunshine fell below 2.36 hours. Taking the median values as the references, lower temperature, lower absolute humidity and windless could significantly increase the risks of influenza activity and last for 4 weeks. A J-shaped nonlinear association was observed between relative humidity and influenza activity; the risk of influenza activity increased with rising relative humidity with 78.26% as the break point. Taking the median value as the reference, high relative humidity could increase the risk of influenza activity and last for 3 weeks. In addition, we found the relationship between aggregate rainfall and influenza activity could be described with a U-shaped curve. Rainfall effect has significantly higher RR than rainless effect. Conclusions: Our study shows that multiple meteorological factors have strong associations with influenza activity in Chongqing, providing evidence for developing a meteorology-based early warning system for influenza to facilitate timely response to upsurge of influenza activity. [ABSTRACT FROM AUTHOR]

Background: Enterovirus 71 (EV71) vaccine, which was put into market in China in 2016, has been viewed as a promising prevention measure against severe and fatal hand, foot and mouth disease (HFMD). This study aimed to investigate the knowledge of HFMD and acceptability of EV71 vaccine among parents of under-five in Chongqing, China. Methodology /Principal findings: A cross-sectional survey was conducted in 2017. A validated questionnaire consisting of three sections including demographic information, knowledge of HFMD, acceptability and reasons for declining vaccination was developed based on literature review. Factors associated with unwillingness to receive EV71 vaccine were explored using multivariate logistic regression. A total of 992 parents finished the questionnaire with a response rate of 91.9%. Awareness of HFMD and EV71 vaccine were reported by 823 (83.0%) parents and 386 (38.9%) parents respectively. Knowledge about HFMD was with a mean score of 5.0 (standard deviation = 3.5) out of a total score of 12. Only 369 (37.2%) participants were classified as with good knowledge level about HFMD. 279 (28.1%) participants had their children received EV71 vaccine and 271 (27.3%) expressed willingness to vaccinate their children after a short-time education about EV71 vaccine. Acceptability of EV71 vaccine increased along with parents' education level (p = 0.008) and HFMD knowledge level (p<0.001). Parents of scattered children had higher acceptability than those of preschool children (p = 0.002). 442 (44.6%) of participants were unwilling to have their children vaccinated with EV71 vaccine. The most common reasons for declining EV71 vaccine were doubts about its safety (56.6%) and efficacy (48.3%), and the necessity of vaccination (38.3%). Physicians and vaccination certificate were the parents' most trusted sources of vaccine information. Conclusions: Parents' knowledge about HFMD was not sufficient, and nearly half of the parents expressed unwillingness to vaccinate their children with EV71 vaccine. Our findings stress that more efforts by health authorities in Chongqing are needed to increase the acceptability of EV71 vaccine, especially among parents of preschool children with lower education level. [ABSTRACT FROM AUTHOR]

Background: Chongqing is the largest municipality and located in Southwestern of China, with over 30 million registered inhabitants. There are few reports regarding the epidemiology of influenza in Chongqing. The objective of the paper is to explore the epidemiology of influenza in Chongqing, in order to provide scientific basis for prevention and control of influenza. Methodology /Principal Findings: From 2011 to 2015, we collected information on influenza-like illness (ILI) patients fulfilling the case definition, and took nasalpharyngeal or throat swabs specimens from ILI cases per week at the 7 sentinel hospitals. Specimens were tested by reverse transcription-polymerase chain reaction(RT-PCR) for influenza. Descriptive epidemiology was applied to analyze the epidemiology and etiology of influenza. A total of 9,696,212 cases were enrolled, of which 111,589 were ILI. Of those 24,868 samples from ILI cases, 13.3% (3,314/24,868) tested positive for influenza virus (65.7% influenza A, 34.1% influenza B, and 0.2% influenza A and B co-infection). Among the influenza A viruses, 71.3% were seasonal influenza A(H3N2) and 28.7% were influenza A(H1N1)pdm09. No cases of seasonal A(H1N1) were detected. The isolation rate was highest in children aged 5–14 years old. Influenza activity consistently peaked during January-March in 2011–2015, and June-July in 2012, 2014 and 2015. Conclusions: Influenza is an important public health problem among ILI patients in Chongqing, especially among school-aged children. It might be beneficial to prioritize influenza vaccination for school-aged children and implement the school-based intervention to prevent and mitigating influenza outbreaks in Chongqing, particularly during the seasonal peaks. [ABSTRACT FROM AUTHOR]

• H7N9 virus spread into Chongqing most likely between late 2016 and early 2017 and resulted in human infections in months. • The most impacted premises and population in the epidemic were LPMs and poultry related workers respectively. • H7N9 virus has probably established in Chongqing posing a long-term threat to public health and local poultry industry. • Preventive measures should focus on rigorous management for LPMs and decreasing the exposure risk to poultry for humans. Influenza A(H7N9) virus has emerged and resulted in human infections in Chongqing, southwestern China since 2017. This study aimed to describe the epidemiological characteristics of the first epidemic in this region. The epidemiological data of patients were collected. Live poultry markets (LPMs), commercial poultry farms (CPFs) and backyard poultry farms (BPFs) were monitored, and poultry sources were registered. Samples derived from the patients, their close contacts, and the environments were tested for influenza A(H7N9) virus by real-time reverse transcriptase polymerase chain reaction. Genetic sequencing and phylogenetic analysis were also conducted. Since the confirmation of the first patient infected with influenza A(H7N9) virus on March 5, 2017, nine patients had been identified within four months in Chongqing. Their mean age was 45 years, 77.8% were male, 66.7% were urban residents and 55.6% were of poultry related occupation. All patients became infected after exposure to live chickens. The median time interval from initial detection of influenza A(H7N9) virus in Chongqing to the patients' onset was 75 days. Since initial detection in February 2017, influenza A(H7N9) virus was detected in 21 (53.8%) counties within four months. The proportion of positive samples was 2.94% (337/11,451) from February 2017 to May 2018, and was higher (χ2 = 75.78, P < 0.001) in LPMs (3.66%, 329/8979) than that in CPFs (0.41%, 5/1229) and BPFs (0.24%, 3/1243). The proportion of positive samples (34.4%, 22/64) at the premises to which the patients were exposed was significantly higher than that (5.7%, 257/4474) in premises with no patients. Phylogenetic analysis indicated that the viruses isolated in Chongqing belonged to the Yangtze River Delta lineage and resembled those circulated in Jiangsu and Anhui provinces between late 2016 and early 2017. Influenza A(H7N9) virus was newly introduced into Chongqing most likely between late 2016 and early 2017, which swept across half of Chongqing territory and resulted in human infections within months. The most impacted premises and population were LPMs and poultry related workers respectively in the epidemic. [ABSTRACT FROM AUTHOR]