Norovirus is one of the leading causes of acute gastroenteritis outbreaks worldwide. This study aimed to identify the epidemiological characteristics of norovirus outbreaks and to provide evidence for public health entities. Specimens and epidemiological survey data were collected to determine if there were differences in the attack rate of norovirus in terms of the year, season, transmission route, exposure setting, and region and to determine whether there were relationships between the reporting interval, the number of illnesses in a single outbreak and the duration of the outbreak. Norovirus outbreaks were reported throughout the year, with seasonal characteristics (i.e., high rates in spring and winter). Among all regions in Shenyang with the exception of Huanggu and Liaozhong, norovirus outbreaks had been reported, and the primary genotype was GII.2[P16]. Vomiting was the most common symptom. The main places of occurrence were childcare institutions and schools. The person-to-person route was the main transmission route. The median duration of norovirus was 3 days (IQR [interquartile range]: 2–6 days), the median reporting interval was 2 days (IQR: 1–4 days), the median number of illnesses in a single outbreak was 16 (IQR: 10–25); there was a positive correlation between these parameters. Norovirus surveillance and genotyping studies still need to be further strengthened to increase knowledge regarding the pathogens and their variant characteristics, to better characterize the patterns of norovirus outbreaks and to provide information for outbreak prevention. Norovirus outbreaks should be detected, reported and handled early. Public health entities and the government should develop corresponding measures for different seasons, transmission routes, exposure settings, and regions.

Human respiratory syncytial virus (HRSV) is a major pathogen of lower respiratory tract infections in children (<5 years) and older individuals, with outbreaks mainly reported among infants in hospital pediatric departments and intensive care units (ICUs). An outbreak of severe neonatal pneumonia occurred in a postpartum center in Shenyang city, China, from January to February 2021. In total, 34 respiratory samples were collected from 21 neonates and 13 nursing staff. The samples were screened for 27 pathogens using a TaqMan low-density array, and 20 samples tested positive for HRSV, including 16 neonates and 4 nursing staff samples. Among the 16 hospitalized neonates, seven were admitted to an ICU and nine to general wards. Four of the nursing staff had asymptomatic infections. To investigate the genetic characteristics of the HRSV responsible for this outbreak, the second hypervariable region (HVR2) sequences of the G gene were obtained from six neonates and two nursing staff. Phylogenetic analyses revealed that all eight sequences (SY strains) were identical, belonging to the HRSV BA9 genotype. Our findings highlight the necessity for strict hygiene and disease control measures so as to prevent cross-infection and further avoid potential outbreaks of severe infectious respiratory diseases. IMPORTANCE Human respiratory syncytial virus (HRSV) is one of the leading causes of acute lower respiratory infections (ALRI) worldwide. In this study, we first reported an outbreak of severe neonatal pneumonia caused by HRSVB BA9 at a postpartum care center in mainland China. Among 20 confirmed cases, 16 were hospitalized neonates with 7 in the ICU ward, and the other four were nursing staff with asymptomatic infections. Our findings highlighted the importance of preventing cross-infection in such postpartum centers.

Diarrhea is one of the leading causes of death among children, especially in the age under 5, but few studies are available on viral diarrhea in Shenyang. To understand the infection status and the relevant epidemiological characteristics of viral diarrhea and to fill gaps of the distribution of viruses across Shenyang in children under the age of 5 with diarrhea, from 2018 to 2020, stool specimens of children with diarrhea aged 0-59 months and surveillance data were collected in Sentinel Hospital of Shenyang. Specimens were then tested to determine the type of viruses, the seasonal and spatial patterns for major viruses were determined. Viruses were identified in 47.9% of the 897 samples from children with diarrhea. The main viruses of stool samples were rotavirus (16.9%, predominant type G9P[8]), calicivirus (14.7%), adenovirus (11.8%), and astrovirus (4.5%). Viral infections were mainly detected in the age of 0-12 months. In the area of Shenyang, Huanggu had the most cases (198, 22.1%), followed by Dadong (137, 15.3%) and Hunnan (135, 15.1%). The positive rate of viruses varied among patients of different ages, seasons, and regions. Public health entities and the government should develop corresponding measures for different age groups, seasons, and regions.

Diarrhea is one of the leading causes of death among children, especially in the age under five, but little data are available on the etiology of viral diarrhea in Shenyang. To understand the infection status and the relevant epidemiological characteristics of viral diarrhea and to fill gaps of how the distribution of viruses change across Shenyang in children under the age of five with diarrhea, stool specimens of children with diarrhea aged 0-59 months and surveillance data was collected from Sentinel Hospital of Shenyang. Rotavirus, calicivirus, adenovirus, and astrovirus 4 viruses were then analyzed, and the proportion of children who tested positive for each pathogen was calculated and seasonal and spatial patterns for major organisms were determined. Viruses were identified in 47.9% of the 897 samples from children with diarrhea. The main viruses of stool samples were rotavirus (16.9%, predominant type G9P[8]), calicivirus (14.7%, norovirus, predominant type GII ), adenovirus (11.8%), and astrovirus (4.5%). Viral infections were mainly detected in the age of 0-12 months. In the area of Shenyang, Huanggu has the most cases (198, 22.1%), followed by Dadong (137, 15.3%) and Hunnan (135, 15.1%). The positive rate of viruses in patients of different ages, seasons, and regions was not same. Public health entities and the government should develop corresponding measures for different age groups, seasons, and regions.

In late December 2019, patients of atypical pneumonia due to an unidentified microbial agent were reported in Wuhan, Hubei Province, China. Subsequently, a novel coronavirus was identified as the causative pathogen which was named SARS-CoV-2. As of 12 February 2020, more than 44 000 cases of SARS-CoV-2 infection have been confirmed in China and continue to expand. Provinces, municipalities and autonomous regions of China have launched first-level response to major public health emergencies one after another from 23 January 2020, which means restricting movement of people among provinces, municipalities and autonomous regions. The aim of this study was to explore the correlation between the migration scale index and the number of confirmed coronavirus disease 2019 (COVID-19) cases and to depict the effect of restricting population movement. In this study, Excel 2010 was used to demonstrate the temporal distribution at the day level and SPSS 23.0 was used to analyse the correlation between the migration scale index and the number of confirmed COVID-19 cases. We found that since 23 January 2020, Wuhan migration scale index has dropped significantly and since 26 January 2020, Hubei province migration scale index has dropped significantly. New confirmed COVID-19 cases per day in China except for Wuhan gradually increased since 24 January 2020, and showed a downward trend from 6 February 2020. New confirmed COVID-19 cases per day in China except for Hubei province gradually increased since 24 January 2020, and maintained at a high level from 24 January 2020 to 4 February 2020, then showed a downward trend. Wuhan migration scale index from 9 January to 22 January, 10 January to 23 January and 11 January to 24 January was correlated with the number of new confirmed COVID-19 cases per day in China except for Wuhan from 22 January to 4 February. Hubei province migration scale index from 10 January to 23 January and 11 January to 24 January was correlated with the number of new confirmed COVID-19 cases per day in China except for Hubei province from 22 January to 4 February. Our findings suggested that people who left Wuhan from 9 January to 22 January, and those who left Hubei province from 10 January to 24 January, led to the outbreak in the rest of China. The 'Wuhan lockdown' and the launching of the first-level response to this major public health emergency may have had a good effect on controlling the COVID-19 epidemic. Although new COVID-19 cases continued to be confirmed in China outside Wuhan and Hubei provinces, in our opinion, these are second-generation cases.

BackgroundIn December of 2019, a novel coronavirus (2019-nCoV) emerged in Wuhan China, which was later named .It quickly spread and as of February 11, 2020, there were 38,800 laboratoryconfirmed cases, 16,067 suspected cases, and 1,113 attributable deaths that have affected all provinciallevel administrative divisions (PLADs) of Mainland China (2).The first confirmed COVID-19 case in Shenyang City, the capital of Liaoning Province, occurred on January 22, 2020, with a total of 9 confirmed cases by January 29, 2020.Of these cases, 4 were clustered in one family.Shenyang CDC immediately launched an investigation to determine routes of transmission, scale of the outbreak, and evidence for epidemic control.

In recent years, there have been a significant influenza activity and emerging influenza strains in China, resulting in an increasing number of influenza virus infections and leading to public health concerns. The aims of this study were to identify the epidemiological and aetiological characteristics of influenza and establish seasonal autoregressive integrated moving average (SARIMA) models for forecasting the percentage of visits for influenza-like illness (ILI%) in urban and rural areas of Shenyang. Influenza surveillance data were obtained for ILI cases and influenza virus positivity from 18 sentinel hospitals. The SARIMA models were constructed to predict ILI% for January-December 2019. During 2010-2018, the influenza activity was higher in urban than in rural areas. The age distribution of ILI cases showed the highest rate in young children aged 0-4 years. Seasonal A/H3N2, influenza B virus and pandemic A/H1N1 continuously co-circulated in winter and spring seasons. In addition, the SARIMA (0, 1, 0) (0, 1, 2)12 model for the urban area and the SARIMA (1, 1, 1) (1, 1, 0)12 model for the rural area were appropriate for predicting influenza incidence. Our findings suggested that there were regional and seasonal distinctions of ILI activity in Shenyang. A co-epidemic pattern of influenza strains was evident in terms of seasonal influenza activity. Young children were more susceptible to influenza virus infection than adults. These results provide a reference for future influenza prevention and control strategies in the study area.