[Performance of screening of contacts of COVID-19 cases in same flight].

Objective: To understand the performance of 2019-nCoV nucleic acid detection in screening of contacts of COVID-19 cases in same flights and provide evidence for the effective screening of persons at high risk for the infection in domestic flights. Methods: The information of passengers who took same domestic flights with COVID-19 cases in China from April 1, 2020 to April 30, 2022 were retrospectively collected,and χ2 test was used to analyze positive nucleic acid detection rates in the passengers in different times before the onsets of the index cases, in different seat rows and in epidemic periods of different 2019-nCoV variants. Results: During the study period, a total of 433 index cases were identified among 23 548 passengers in 370 flights. Subsequently, 72 positive cases of 2019-nCoV nucleic acid were detected in the passengers, in whom 57 were accompanying persons of the index cases. Further analysis of the another 15 passengers who tested positive for the nucleic acid showed that 86.67% of them had onsets or positive detections within 3 days after the diagnosis of the index cases, and the boarding times were all within 4 days before the onsets of the index cases. The positive detection rate in the passengers who seated in first three rows before and after the index cases was 0.15% (95%CI: 0.08%-0.27%), significantly higher than in the passengers in other rows (0.04%, 95%CI: 0.02%-0.10%, P=0.007),and there was no significant difference in the positive detection rate among the passengers in each of the 3 rows before and after the index cases (P=0.577). No significant differences were found in the positive detection rate in the passengers, except the accompanying persons, among the epidemics caused by different 2019-nCoV variants (P=0.565). During the Omicron epidemic period, all the positive detections in the passengers, except the accompanying persons, were within 3 days before the onset of the index cases. Conclusions: The screening test of 2019-nCoV nucleic acid can be conducted in the passengers took the same flights within 4 days before the onsets of the index cases on board. Passengers who seated within 3 rows from the index cases can considered as the close contacts at high risk for 2019-nCoV, for whom screening should be conducted first and special managements are needed. The passengers in other rows can be classified as general risk persons for screening and management.

[Epidemiological characteristics of typhoid fever and paratyphoid fever in China, 2004-2020].

Objective: To analyze the incidence trend and epidemiological characteristics of typhoid fever and paratyphoid fever in China from 2004 to 2020, understand the high-incidence population and hotspot areas, and provide evidences to develop more targeted prevention and control measures. Methods: The descriptive epidemiological method and spatial analysis method were applied to analyze the epidemiological characteristics of typhoid fever and paratyphoid fever in China during this period by using the surveillance data collected from the National Notifiable Infectious Disease Reporting System of Chinese Center for Disease Control and Prevention. Results: A total of 202 991 cases of typhoid fever were reported in China from 2004 to 2020. More cases occurred in men than in women (sex ratio: 1.18∶1). Most cases were reported in adults aged 20-59 years (53.60%). The incidence rate of typhoid fever decreased from 2.54/100 000 in 2004 to 0.38/100 000 in 2020. The highest incidence rate was reported in young children aged <3 years after 2011, ranging from 1.13/100 000 to 2.78/100 000, and during this period the proportion of cases in this age group increased from 3.48% to 15.59%. The proportion of the cases in the elderly aged ≥60 years increased from 6.46% in 2004 to 19.34% in 2020. The hotspot areas existed in Yunnan, Guizhou, Guangxi and Sichuan Provinces and expanded to Guangdong, Hunan, Jiangxi, and Fujian Provinces. A total of 86 226 paratyphoid fever cases were reported from 2004 to 2020, the male to female ratio of the cases was 1.21∶1. Most cases were reported in adults aged 20-59 years (59.80%). The incidence rate of paratyphoid fever decreased from 1.26/100 000 in 2004 to 0.12/100 000 in 2020. The highest incidence rate of paratyphoid fever was in young children aged <3 years after 2007, ranging from 0.57/100 000 to 1.19/100 000, and during this period the proportion of the cases in this age group increased from 1.48% to 30.92%. The proportion of the cases in the elderly aged ≥60 years increased from 4.52% in 2004 to 22.28% in 2020. The hotspot areas expanded to the east, including Guangdong, Hunan and Jiangxi Provinces, from Yunnan, Guizhou, Sichuan, and Guangxi Provinces. Conclusions: The results showed a low level of incidence of typhoid fever and paratyphoid fever in China with a trend of decreasing per year. The hotspots were mainly in the of Yunnan, Guizhou, Guangxi and Sichuan Provinces, with an expanding trend to eastern China. It is necessary to strengthen the typhoid fever and paratyphoid fever prevention and control in southwestern China, among young children aged <3 years and the elderly aged ≥60 years.

[Epidemiological characteristics of norovirus acute gastroenteritis outbreaks and influencing factors in China, 2007-2021].

Objective: To analyze the epidemiological characteristics of norovirus-caused acute gastroenteritis outbreaks in China, identify the factors influencing the scale of outbreaks, and provide scientific evidences for early control of norovirus infection outbreaks. Methods: The descriptive epidemiological analysis approach was applied to analyze the incidence of national norovirus infection outbreaks by using the data from the Public Health Emergency Event Surveillance System in China from January 1, 2007 to December 31, 2021. The unconditional logistic regression model was applied to analyze the risk factors that affected the outbreaks' scale. Results: A total of 1 725 norovirus infection outbreaks were recorded in China from 2007 to 2021, with an upward trend in the number of the reported outbreaks. The southern provinces had their annual outbreak peaks from October to March; the northern provinces had two outbreak peaks from October to December and from March to June annually. The outbreaks occurred mainly in southeastern coastal provinces with a trend of gradual spread to central, northeastern and western provinces. The outbreaks mainly occurred in schools and childcare setting (1 539 cases, 89.22%), followed by enterprises and institutions (67 cases, 3.88%) and community households (55 cases, 3.19%). Human to human transmission was the main infection route (73.16%), and norovirus GⅡ genotype was the predominate pathogen causing the outbreaks (899 cases, 81.58%). The time interval between the onset of the primary case and the outbreak reporting M (Q1, Q3) was 3 (2, 6) days and the case number of the outbreak M (Q1, Q3) was 38 (28, 62). The timeliness of outbreak reporting was improved in recent years and the scale of the outbreaks showed a decreasing trend over the years, the differences in reporting timeliness and outbreak scale among different settings were significant (P<0.001). The factors that affected outbreaks' scale included the outbreak setting, transmission route, outbreak reporting timeliness and type of living areas (P<0.05). Conclusions: From 2007 to 2021, the number of the norovirus-caused acute gastroenteritis outbreaks increased in China and the more areas were affected. However, the outbreak scale showed a decreasing trend and the outbreak reporting timeliness was improved. It is important to further improve the surveillance sensitivity and reporting timeliness for the effective control of the outbreak scale.

[Epidemiological characteristics of severe cases of hand, foot, and mouth disease in China, 2008-2018].

Objective: To characterize the epidemiology of severe hand, foot and mouth disease (HFMD) in China from 2008 to 2018 and provide evidence for the prevention and control of severe HFMD. Methods: The incidence data of severe HFMD cases from 2008 to 2018 were collected from the National Notifiable Infectious Diseases Reporting System of Chinese Center for Disease Control and Prevention. Descriptive epidemiological methods were used to analyze distributions, pathogen constituent and change of severe HFMD. Joinpoint regression model was used to analyze the trends of severity rate, proportion of severe cases and severe fatality rate. Results: From 2008 to 2018, a total of 157 065 cases of severe HFMD were reported in China, with an average annual case-severity rate of 1.05/100 000, a severe case proportion of 0.76% and a severity-fatality rate of 2.34%. The severity rate and the proportion of severe cases showed a downward trend after 2010, and severe fatality rate decreased significantly after 2014. The severe cases mainly occurred in infants aged ≤3 years (91.47%), more boys were affected than girls (1.78∶1). The median age of severe HFMD cases caused by EV-A71 was highest (1.99 years) and increased year by year, other enterovirus infection cases accounted for a higher proportion in infants aged ≤1 year (66.56%). The incidence peak occurred during April-July, other enteroviruses replaced EV-A71 as the predominant serotype in 2018 (61.97%). The incidence of severe HFMD were high in some provinces in southwestern, central and eastern China. Conclusion: The overall severity rate, proportion of severe cases and severe fatality rate of HFMD in the mainland of China have shown a downward trend. The predominant pathogen in some provinces has changed from EV-A71 to other enteroviruses. It is necessary to strengthen the prevention and control of HFMD in key population, high incidence seasons and areas and carry out the surveillance of various pathogens of HFMD.

[Epidemiological characteristics of fatal cases of hand, foot, and mouth disease in children under 5 years old in China, 2008-2018].

Objective: To understand the epidemiological characteristics and risk factors of fatal cases of hand, foot, and mouth disease (HFMD) in children under 5 years old in China from 2008 to 2018, and provide evidence for the development of targeted prevention and control measures and reduction of the incidence of fatal HFMD cases. Methods: The incidence data of reported HFMD cases in China during 2008-2018 were collected from the National Notifiable Disease Surveillance Reporting System of China for the analyses on the demographic characteristics, spatial distribution, diagnosis or reporting and pathogen spectrum of the HFMD cases. Then the risk factors causing deaths were analyzed by using logistic regression model. Results: From 2008 to 2018, a total of 3 646 fatal cases of HFMD in children under 5 years old were reported in China. There were more fatal HFMD cases in boys than in girls (1.82∶1), the death mainly occurred in age group 0 to 2 years (87.71%). Adjusted mortality rate of HFMD in children under 5 years old in China declined from 0.87 per 100 000 in 2010 to 0.11 per 100 000 in 2018 (APC=-23.20%). In the 2 523 laboratory-confirmed deaths, 2 323 (92.07%) were EV-A71 infections, but the constituents of CV-A16 and other enterovirus infections increased. The interval from onset to diagnosis M=2(P(25)-P(75):2-4)d. The interval from onset to death M=3(P(25)-P(75):2-4)d. Age between 0 and 1 years, EV-A71 infection, longer interval between onset and diagnosis, and living in rural area were the risk factors causing fatal HFMD cases. Conclusions: The number of the fatal cases, the rate of mortality and case fatality HFMD in China had shown downward trends since 2010. EV-A71 is still the main pathogen causing fatal cases, but we should pay more attention to gene pattern of the other enteroviruses except EV-A71 and CV-A16. To reduce the risk of the fatal cases we should strengthen the health education about the immunization of EV-A71 inactivated vaccines and reduce the interval from onset to diagnosis in young children in western provinces and rural areas.

[Application of moving epidemic method in establishing epidemic intensity threshold of hand, foot, and mouth disease in southern China].

Objective: To evaluate the incidence intensity of hand, foot, and mouth disease (HFMD) in 2018/2019 season in southern China by Moving Epidemic Method (MEM), and compare the intensity among provinces, so as to provide basis for optimizing the allocation of public health resources. Methods: The weekly incidence data of HFMD of children under 5 years old in 15 provinces of southern China from March 1, 2012 to February 28, 2019 were collected from Disease Surveillance Reporting System of Chinese Center for Disease Control and Prevention, and the epidemic intensity threshold of each province in southern China during this period was calculated and evaluated by MEM. Results: In the first incidence peak of 2018/2019 HFMD season, in 15 provinces in the south China, 6 provinces (Jiangsu, Zhejiang, Jiangxi, Chongqing, Sichuan and Yunnan) reported very high incidence rates in children under 5 years old while Guangdong, Guangxi and Hainan provinces had low incidence level. In the second incidence peak, the incidences in 6 provinces (Shanghai, Jiangsu, Zhejiang, Chongqing, Sichuan and Yunnan) reached very high levels. The incidences in remaining provinces also reached medium or high levels. In most provinces, the thresholds in the first incidence peak were higher than those in the second incidence peak, but Chongqing and Sichuan were different. The results of model validation showed that the sensitivity and specificity of MEM were higher than 70% except for Hainan, Chongqing and Yunnan. Conclusions: For southern provinces with two incidence peaks in HFMD season, MEM can be used to determine the epidemic intensity thresholds of different incidence peaks by dividing the disease season to analyze the incidence intensity of HFMD in different stages. The epidemic intensity threshold established by MEM integrates the historical data, and the province (city) with extremely high epidemic level identified represents that the province (city) has an abnormal increase compared with the historical incidence level, which requires more attention from all areas and timely implementation of prevention and control measures.

[Epidemiological characteristics of amoebic dysentery in China, 2015-2018].

Objective: To understand the characteristics and changes of the incidence of amoebic dysentery in China during 2015-2018, explore the causes of high incidence in some areas and provide a data base for the development of national prevention and control strategies and measures. Methods: Data were collected from the infectious disease reporting management information system from Chinese Disease Control and Prevention. To understand the seasonal, population and area distributions of amoebic dysentery, descriptive epidemiological method and software SPSS 16.0 were used to analyze the amoebic dysentery data. Results: A total of 4 366 amoebic dysentery cases were reported without death in China during 2015-2018. The reported average annual incidence was 0.08/100 000, and the overall proportion of laboratory confirmed cases was 68.23%(2 979/4 366). Amoeba dysentery mainly occurred during May to October. One seasonal peak was observed in 2015 and 2017 (July and June, respectively), and two seasonal peaks were observed in 2016 and 2018 (June and October). The patients were mainly children aged under 5 years (42.28%, 1 846/4 366), and the incidence rate decreased with age in children aged under 10 years. Of these, children under 1 years of age had the highest incidence rate (1.28/100 000). The number of cumulative reported cases in Guangxi, Henan, Guangdong, Heilongjiang and Jiangxi provinces ranked top five from 2015-2018, accounting for 64.50% (2 816/4 366) of the total. The cumulative cases in Dongxing county, Guangxi, in Suixian county, Henan and in Ranghulu district, Heilongjiang, respectively accounted for more than 50.00% of the total number of cases in their provinces. Conclusions: The incidence rate of amoebic dysentery reported in China during 2015-2018 showed a decreasing trend, with a higher incidence in children under 5 years old and a higher number of cases in some areas. It is suggested to further investigate and analyze the diagnosis and reporting of amoeba dysentery in key areas and promote the update of the diagnostic standards for amoeba dysentery.

[Review on the etiology and complications of hand, foot and mouth disease, using data from the national sentinel surveillance program, in China, 2015-2016].

Objective: To understand the characteristics relating to the etiology and complications of hand, foot and mouth disease (HFMD) based on data from the pilot National Sentinel Surveillance (NSS) program so as to explore the feasibility, advantages and disadvantages of the NSS. Methods: Data were extracted from the NSS system, conducted in 11 provinces of China from November 2015 to October 2016. Characteristics regarding the etiology, complications of HFMD and factors related to the positive rates of HFMD specimens were analyzed under the logistic regression method by SPSS 20.0 software. Results: A total of 4 783 specimens were collected, including 3 390 from mild, 1 390 from severe and 3 from death cases. The overall positive rate was 81.43% (3 895/4 783). Other enteroviruses (non EV71/Cox A16 enteroviruses) appeared the major serotype (52.68%, 1 482/2 813) for mild infection of the disease while EV71 was for the severe cases (65.31%, 706/1 081). The serotype spectrum revealed by the pilot NSS was almost identical with the existing surveillance system. Other enteroviruses tended to infect younger children (χ(2)=130.17, P<0.001) than EV71 and Cox A16, in China. The multivariate logistic regression results showed that higher positive rate was associated with specimens which were collected from males, at children' hospitals, in peak seasons, timely and in stools. The positive rates presented downwarding trends with the extension of the onset-sampling interval (χ(2)=14.47, P<0.001 in stool specimen; χ(2)=31.99, P<0.001 in throat swab; χ(2)=24.26, P<0.001 in anal swab). Aseptic meningitis, non-brainstem encephalitis and brainstem encephalitis appeared the top three complications of both EV71-associated and other enteroviruses-associated severe HFMD cases. Conclusions: Factors as gender, season/place/timeliness of specimen collection, and types of hospital all appeared independently influenced the positive rates. NSS seemed feasible to be used as an alternative or supplement tool to the existing surveillance program in China.

[Temporal-spatial analysis of bacillary dysentery in the Three Gorges Area of China, 2005-2016].

Objective: To analyze the spatial and temporal distributions of bacillary dysentery in Chongqing, Yichang and Enshi (the Three Gorges Area) from 2005 to 2016, and provide evidence for the disease prevention and control. Methods: The incidence data of bacillary dysentery in the Three Gorges Area during this period were collected from National Notifiable Infectious Disease Reporting System. The spatial-temporal scan statistic was conducted with software SaTScan 9.4 and bacillary dysentery clusters were visualized with software ArcGIS 10.3. Results: A total of 126 196 cases were reported in the Three Gorges Area during 2005-2016, with an average incidence rate of 29.67/100 000. The overall incidence was in a downward trend, with an average annual decline rate of 4.74%. Cases occurred all the year round but with an obvious seasonal increase between May and October. Among the reported cases, 44.71% (56 421/126 196) were children under 5-year-old, the cases in children outside child care settings accounted for 41.93% (52 918/126 196) of the total. The incidence rates in districts of Yuzhong, Dadukou, Jiangbei, Shapingba, Jiulongpo, Nanan, Yubei, Chengkou of Chongqing and districts of Xiling and Wujiagang of Yichang city of Hubei province were high, ranging from 60.20/100 000 to 114.81/100 000. Spatial-temporal scan statistic for the spatial and temporal distributions of bacillary dysentery during this period revealed that the temporal distribution was during May-October, and there were 12 class Ⅰ clusters, 35 class Ⅱ clusters, and 9 clusters without statistical significance in counties with high incidence. All the class Ⅰ clusters were in urban area of Chongqing (Yuzhong, Dadukou, Jiangbei, Shapingba, Jiulongpo, Nanan, Beibei, Yubei, Banan) and surrounding counties, and the class Ⅱ clusters transformed from concentrated distribution to scattered distribution. Conclusions: Temporal and spatial cluster of bacillary dysentery incidence existed in the three gorges area during 2005-2016. It is necessary to strengthen the bacillary dysentery prevention and control in urban areas of Chongqing and Yichang.

[Surveillance data on typhoid fever and paratyphoid fever in 2015, China].

Objective: Through analyzing the surveillance data on typhoid fever and paratyphoid fever in 2015 to understand the related epidemiological features and most possible clustering areas of high incidence. Methods: Individual data was collected from the passive surveillance program and analyzed by descriptive statistic method. Characteristics on seasonal, regional and distribution of the diseases were described. Spatial-temporal clustering characteristics were estimated, under the retrospective space-time method. Results: A total of 8 850 typhoid fever cases were reported from the surveillance system, with incidence rate as 0.65/100 000. The number of paratyphoid fever cases was 2 794, with incidence rate as 0.21/100 000. Both cases of typhoid fever and paratyphoid fever occurred all year round, with high epidemic season from May to October. Most cases involved farmers (39.68%), children (15.89%) and students (12.01%). Children under 5 years showed the highest incidence rate. Retrospective space-time analysis for provinces with high incidence rates would include Yunnan, Guangxi, Guizhou, Hunan and Guangdong, indicating the first and second class clusters were mainly distributed near the bordering adjacent districts and counties among the provinces. Conclusion: In 2015, the prevalence rates of typhoid fever and paratyphoid fever were low, however with regional high prevalence areas. Cross regional transmission existed among provinces with high incidence rates which might be responsible for the clusters to appear in these areas.

[Severe cases with hand, foot and mouth disease: data based on national pilot hand, foot and mouth disease surveillance system].

Objective: To investigate the clinical severity, etiological classification and risk factors of severe cases with hand, foot and mouth disease (HFMD). Methods: A total of 1 489 records on severe and fatal HFMD cases reported to the national pilot surveillance system of HFMD were used to analyze the demographic, medical treatment, etiological classification of the cases. Treatment outcome related risk factors were also studied with multi-variable stepwise logistic regression method. Results: Seven out of the 1 489 severe HFMD cases died of this disease. A total of 960 (72.9%) were under three years old and 62.9% were male and most of the cases (937, 62.9%) resided in rural areas. Among all the cases, 494 (33.2%) went to seek the first medical assistance at the institutions of village or township level. Durations between disease onset and first medical attendance, being diagnosed as the disease or diagnosed as severe cases were 0(0-1) d, 1 (0-2) d and 2 (1-4) d, respectively. In total, 773 (51.9%) of the severe HFMD cases were diagnosed as with aseptic meningitis, 260 (17.5%) with brainstem encephalitis, 377 (25.3%) with non-brainstem encephalitis, 6 (0.4%) with encephalomyelitis, 1 (0.1%) with acute flaccid paralysis, 4 (0.3%) with pulmonary hemorrhage/pulmonary edema and 68 (4.6%) with cardiopulmonary failure. Of the etiologically diagnosed 1 217 severe and fatal HFMD cases, 642 (52.8%) were with EV71, other enterovirus 261 (21.5%), Cox A16 36 (3.0%), 1 (0.1%) with both EV71 and Cox A16. However, 277 (22.8%) showed negative on any pathogenic virus. Complication (Z=3.15, P=0.002) and duration between onset and diagnosed as severe cases (Z=3.95, P<0.001) were shown as key factors related to treatment outcomes. Conclusions: Most severe HFMD cases appeared in boys, especially living in the rural areas. Frequently seen complications would include aseptic meningitis, non-brainstem encephalitis and brainstem encephalitis. EV71 was the dominant etiology for severe and fatal cases. Early diagnosis and complication control were crucial, related to the treatment outcome of HFMD.

Impact of new migrant populations on the spatial distribution of tuberculosis in Beijing.

SETTING AND OBJECTIVES: The tuberculosis (TB) case notification rate in Beijing has been increasing since 2000. Migration was speculated to play an important role in promoting the growth of the epidemic. The identification of spatial clusters of TB can be a key indicator for targeting limited public health resources. METHODS: Spatial modelling was applied to the 220 towns of Beijing and summarised for the 18 districts, which were combined into four functional areas in 2005 and 2006. Population density was combined with the numbers of TB cases, and TB incidence data was used to identify high rate clusters. A negative binomial regression model was used to confirm the association between TB and migration status in Beijing. RESULTS: There were 4584 TB cases among permanent residents and 2838 among migrants. TB cases and population were most densely grouped in four central districts. High-rate TB clusters in both permanent residents and migrants were detected in the 'New Districts for Urban Development' and Chaoyang District in 2005 and 2006. Migration and the population growth rate of new migrants are contributing to the TB increase in Beijing. CONCLUSIONS: The increasing migrant population has had a drastic influence on the spatial distribution of TB in Beijing. Spatial analysis could provide additional information in addition to common incidence plots.

Clinical and pathological characteristics of carcinosarcoma of the esophagus: report of four cases.

Carcinosarcoma of the esophagus is a rare malignant neoplasm composed of both carcinomatous and sarcomatous elements. Four out of 850 patients with carcinoma of the esophagus or the cardiac portion of the stomach undergoing operation at Capital Hospital, Beijing, had carcinosarcoma of the esophagus. They ranged from 50 to 58 years old, but only 45% of all 850 patients with carcinoma were in the age group from 51 through 60 years old. All 4 patients with carcinosarcoma of the esophagus were men. On barium swallow esophagogram, the 4 patients had a characteristic intraluminal polypoid lesion in the middle third of the esophagus. Such lesions of the esophagus also can occur in patients with benign fibrovascular polyps, leiomyoma, and the polypoid form of esophageal carcinoma and esophageal melanoma. The last two can be differentiated from carcinosarcoma only by pathological examination after excision. After radical excision and esophagogastrostomy, the 4 patients were followed up for 19, 4, 4, and 3 years. They were in good condition without recurrence.