Epidemiological and clinical profile of pediatric hepatitis B virus infections in Wuhan: a retrospective cohort study

BACKGROUND

Hepatitis B virus (HBV) remains a substantial public health safety concern drawing considerable attention in China and globally. The detection of HBV serological markers can enable the assessment of HBV infection and replication status in vivo and evaluate the body's protection against HBV. Therefore, this study aims to identify the epidemiological and clinical characteristics of HBV infection in children to prevent and control HBV infection in Wuhan areas.

METHODS

We conducted an extensive retrospective cohort analysis of 115,029 individuals aged 0-18 years who underwent HBV serological markers detection for HBV infection in hospital between 2018 and 2021 using Electrochemiluminescence immunoassay. We generated descriptive statistics and analysed HBV infection's epidemiological and clinical characteristics between different sex and age groups.

RESULTS

The overall positive detection rates of HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb in all participants were 0.13%, 79.09%, 0.17%, 2.81%, and 5.82%, respectively. The positive rate of HBeAb and HBcAb in males was significantly lower than that in females (2.64% vs. 3.13%, 5.56% vs. 6.29%) (P < 0.05). Twenty-two distinct HBV serological expression patterns were revealed. Among them, 8 common expression patterns accounted for 99.63%, while the remaining 14 uncommon expression patterns were primarily observed in neonatal patients with HBV infection. There are no significant differences in serological patterns based on sex (P < 0.05). The overall HBV infection detection rate was 5.82% [range 5.68-5.95] and showed a declining yearly trend. The rate in females was higher than that in males 6.29% [6.05, 6.35] vs. 5.56% [5.39, 5.59]. The overall HBV diagnostic rate over 4 years was 0.20% [0.17, 0.22], and the rate declined yearly. The prevalence of acute infection was higher than that of other infection types before 2019, but the incidence of unclassified infection showed a significant upward trend after 2019.

CONCLUSIONS

While the overall HBV infection detection rate in children has decreased year by year, the infection rate remains high in children under one year and between 4 and 18 years. This continued prevalence warrants heightened attention and vigilance.

[Epidemiological and clinical characteristics of human ocular helaziasis in China from 2011 to 2022 based on bibliometrics]

OBJECTIVE

To understand the clinical and epidemiological characteristics of human ocular thelaziasis patients in China.

METHODS

Case reports regarding human ocular thelaziasis cases in China were retrieved in international and national electronic databases, including CNKI, VIP, CBM, Traditional Chinese Medical Literature Analysis and Retrieval System, Wanfang Database, PubMed and Web of Science from 2011 to 2022. Patients' gender, age, clinical symptoms, treatment, recurrence, site of infections, time of onset, affected eye, affected sites, number of infected Thelazia callipaeda, sex of T. callipaeda and source of infections were extracted for descriptive analyses.

RESULTS

A total of 85 eligible publications were included, covering 101 cases of human ocular thelaziasis, including 57 males (56.44%) and 44 females (43.56%) and aged from 3 months to 85 years. The main clinical manifestations included foreign body sensation (56 case-times, 22.49%), eye itching (38 case-times, 15.26%), abnormal or increased secretions (36 case-times, 14.46%), tears (28 case-times, 11.24%) and eye redness (28 case-times, 11.24%), and conjunctival congestion (50 case-times, 41.67%) was the most common clinical sign. The most common main treatment (99/101, 98.02%) was removal of parasites from eyes using ophthalmic forceps, followed by administration with ofloxacin and pranoprofen. In publications presenting thelaziasis recurrence, there were 90 cases without recurrence (97.83%) and 2 cases with recurrence (2.17%). Of all cases, 51.96% were reported in four provinces of Hubei, Shandong, Sichuan, Hebei and Henan, and ocular thelaziasis predominantly occurred in summer (42.19%) and autumn (42.19%). In addition, 56.45% (35/62) had a contact with dogs.

CONCLUSIONS

The human thelaziasis cases mainly occur in the continental monsoon and subtropical monsoon climate areas such as the Yellow River and the Yangtze River basin, and people of all ages and genders have the disease, with complex clinical symptoms and signs. Personal hygiene is required during the contact with dogs, cats and other animals, and individual protection is required during outdoor activities to prevent thelaziasis.

Analysis of the Epidemiologic Characteristics of Children with Hand, Foot and Mouth Disease in China

Background

We aimed to investigate the epidemiological characteristics of hand, foot and mouth disease (HFMD) and provide recommendations for its control and prevention.

Methods

A descriptive epidemiological analysis was designed for HFMD in children through direct network report from 2015 to 2019.

Results

From 2015 to 2019, a total 27,395 HFMD cases were reported at Infection Clinic of Shanghai Children's Hospital, Shanghai, China, accounting for 79.24% of the number of reported notifiable infectious disease cases (34,573). The cases number increased since May and reached a peak from June to September, then decreased from October to December with a second small peak in some years. The proportion of cases in boys is higher than in girls (59.7% vs. 40.3%). The cases number of stay-at-home children was higher in 2016 and 2018 (60.07% and 60.95%) than in 2019 (33.47%), and that of kindergarten children and students in 2019 (51.73% and 9.75%) was significantly higher than in other years. Overall, 22606 cases were reported in <5 years group, accounting for 82.52% of the total number of cases during 2015-2019. The proportion of the cases in 5-10 and >10 years groups increased year by year from 2015 to 2019, which is statistically significant. (χ2=71.105, P=0.00; χ2=78.413, P=0.00).

Conclusion

The epidemiological characteristics of HFMD had changed during 2015-2019. Analysis of these data can provide helpful evidence to prevention and early treatment of the HFMD, and identification severe cases and handling the outbreaks.

Current status of hand-foot-and-mouth disease

Hand-foot-and-mouth disease (HFMD) is a viral illness commonly seen in young children under 5 years of age, characterized by typical manifestations such as oral herpes and rashes on the hands and feet. These symptoms typically resolve spontaneously within a few days without complications. Over the past two decades, our understanding of HFMD has greatly improved and it has received significant attention. A variety of research studies, including epidemiological, animal, and in vitro studies, suggest that the disease may be associated with potentially fatal neurological complications. These findings reveal clinical, epidemiological, pathological, and etiological characteristics that are quite different from initial understandings of the illness. It is important to note that HFMD has been linked to severe cardiopulmonary complications, as well as severe neurological sequelae that can be observed during follow-up. At present, there is no specific pharmaceutical intervention for HFMD. An inactivated Enterovirus A71 (EV-A71) vaccine that has been approved by the China Food and Drug Administration (CFDA) has been shown to provide a high level of protection against EV-A71-related HFMD. However, the simultaneous circulation of multiple pathogens and the evolution of the molecular epidemiology of infectious agents make interventions based solely on a single agent comparatively inadequate. Enteroviruses are highly contagious and have a predilection for the nervous system, particularly in child populations, which contributes to the ongoing outbreak. Given the substantial impact of HFMD around the world, this Review synthesizes the current knowledge of the virology, epidemiology, pathogenesis, therapy, sequelae, and vaccine development of HFMD to improve clinical practices and public health efforts.

[Epidemiological characteristics and influencing factors of Blastocystis hominis infection among children with diarrhea under five years of age in Guangzhou City]

OBJECTIVE

To investigate the prevalence and influencing factors of Blastocystis hominis infection among children with diarrhea under five years of age in Guangzhou City.

METHODS

Children with diarrhea under 5 years of age admitted to Guangzhou Children's hospital, Guangzhou Maternity and Child Healthcare Hospital and Guangzhou Women and Children's Medical Center during the period between January 1 and December 31, 2020, were enrolled. Participants' demographics, living environments and health status were collected using questionnaire surveys. Stool samples were collected from participants and nucleic acid was extracted. B. hominis infection was identified using PCR assay and sequence alignment, and the factors affecting B. hominis infection among children with diarrhea under 5 years of age were identified using univariate analysis and multivariate logistic regression analysis.

RESULTS

A total of 684 children with diarrhea under 5 years of age were enrolled, including 468 male children and 216 female children, with a mean age of (1.79 ± 1.12) years. The overall prevalence of B. hominis infection was 4.97% [34/684, 95% confidential interval (CI): (3.59%, 6.86%)] among participants, and there was no significant difference in the prevalence of B. hominis infection between children with chronic [7.52% (20/266), 95% CI: (4.92%, 11.33%)] and acute diarrhea [3.35% (14/418), 95% CI: (2.01%, 5.54%)] (χ² = 5.983, P = 0.014). Multivariate logistic regression analysis identified keeping pet [odds ratio (OR) = 6.298, 95% CI: (2.711, 14.633)], drinking non-tap water [OR = 4.522, 95% CI: (1.769, 11.561)], lactose intolerance [OR = 4.221, 95% CI: (1.043, 17.087)], antibiotic use [OR = 0.125, 95% CI: (0.017, 0.944)] and chronic diarrhea [OR = 2.172, 95% CI: (1.018, 4.637)] as factors affecting B. hominis infection among children with diarrhea under 5 years of age in Guangzhou City.

CONCLUSIONS

B. hominis infections is detected in children with diarrhea under five years of age in Guangzhou City. Improving home environments and pet-keeping hygiene is recommended to reduce the likelihood of B. hominis infection among children.

Epidemiological Characteristics of Occupational Cancers Reported - China, 2006-2020

Introduction

Occupational cancers are a major threat to workers' health in China. The latest version of the Classification and Catalogue of the Occupational Diseases includes 11 occupational cancers. This study analyzed the epidemiological characteristics of occupational cancers in China reported to the National Occupational Disease Reporting System during 2006-2020.

Methods

Occupational cancers reported during 2016-2020 were obtained from the National Occupational Disease Reporting System. Epidemiological characteristics were analyzed by year, region, industry, gender, age at diagnosis, and exposure duration to occupational hazards.

Results

Overall, a total of 1,116 cases of occupational cancers were reported between 2006 and 2020. The main types reported were leukemia caused by benzene exposure (511, 45.79%), lung cancer caused by coke oven exhaust exposure (266, 23.84%), and lung cancer and mesothelioma caused by asbestos exposure (226, 20.25%). There were 6 provincial-level administrative divisions (PLADs) that had reported over 50 new cases in the last 15 years. Most cases (913, 81.18%) were distributed in the manufacturing industry. There were 870 (77.96%) male cases and 246 (22.04%) female cases. The average age at diagnosis of all reported cases was 51.91±15.85 years, and the median exposure duration to occupational hazards was 12 (5.29-23.25) years.

Conclusions

There is a large discrepancy between the high morbidity of occupational cancers and a low number of cases diagnosed and reported cases. Occupational cancers in China may be underestimated, and comprehensive measures should be taken to improve the diagnosis and reporting of occupational cancers.

[Epidemic status of imported malaria before and after malaria elimination in Jiaozuo City of Henan Province]

OBJECTIVE

To analyze and compare the epidemiological characteristics of imported malaria in Jiaozuo City before and after malaria elimination, so as to provide insights into the malaria surveillance during the post-elimination stage and prevention of re-establishment of imported malaria.

METHODS

Data pertaining to the epidemic situation and individual investigation of malaria in Jiaozuo City before (from 2010 to 2016) and after malaria elimination (from 2017 to November, 2020) were captured from the National Notifiable Disease Reporting System and the Information System for Parasitic Diseases Control and Prevention of Chinese Center for Disease Control and Prevention and were analyzed statistically.

RESULTS

A total of 74 imported malaria cases were reported in Jiaozuo City from 2010 to 2021. Imported cases were predominantly Plasmodium falciparum malaria cases in Jiaozuo City before and after malaria elimination, and there was no significant difference in the proportion of malaria parasite species (χ² = 0.234, P > 0.05). The imported malaria cases was predominantly reported in Wuzhi County, and was identified in overseas male farmers and businessmen at ages of 20 to 59 years, while the greatest number of imported malaria cases was reported in June and December before and after malaria elimination. The imported malaria cases predominantly acquired malaria parasite infections in sub-Saharan African countries; however, the proportion of imported malaria cases returning from Southeast Asian counties increased after malaria elimination than before malaria elimination (χ² = 5.989, P < 0.05). The longest duration from onset to definitive diagnosis of malaria reduced from 27 days before malaria elimination to 18 days after malaria elimination, and the median duration reduced from 3 days to 2 days, while the proportion of definitive diagnosis of malaria increased from 60.47% before malaria elimination to 83.87% after malaria elimination (χ² = 4.724, P < 0.05). In addition, the proportion of malaria cases definitively diagnosed and reported by medical institutions increased after malaria elimination than before malaria elimination (χ² = 5.406, P < 0.05).

CONCLUSIONS

The imported malaria patients were predominantly P. falciparum malaria cases in Jiaozuo City during 2010 to 2021, and the patient's medical care-seeking awareness and medical staff's diagnosis and treatment ability have improved after malaria elimination. It is necessary to strengthen and improve malaria surveillance and response system and prevent the re-establishment of overseas imported malaria.

[Epidemiological characteristics of imported malaria in Zhengzhou City from 2016 to 2020]

OBJECTIVE

To analyze the epidemiological characteristics of reported imported malaria cases in Zhengzhou City from 2016 to 2020, so as to provide insights into the management of imported malaria in the city.

METHODS

All data pertaining to cases with definitive diagnosis of malaria in Zhengzhou City from 2016 to 2020 were captured from the National Notifiable Disease Report System and the Information Management System for Parasitic Disease Control in China, including individual demographic data, and malaria onset, initial diagnosis and definitive diagnosis data. All data were descriptively analyzed. The duration from malaria onset to initial diagnosis, from initial diagnosis to definitive diagnosis and from onset to definitive diagnosis was compared among cases. In addition, the diagnoses of imported malaria cases in which definitive diagnosis was made were compared with the reexaminations by Zhengzhou Municipal Malaria Diagnosis Reference Laboratory.

RESULTS

A total of 302 cases with definitive diagnosis of malaria were reported in Zhengzhou City from 2016 to 2020, and all were imported cases, with Plasmodium falciparum malaria as the predominant type (230 cases, 76.2%). There were 293 malaria cases imported from Africa (293 cases, 97.0%), which mainly included Nigeria (48 cases, 15.9%), Angola (40 cases, 13.2%), and the Democratic Republic of the Congo (29 cases, 9.6%). There was no obvious seasonality found in the date of malaria onset and time of reporting malaria. The ratio of male to female malaria cases was 49.3:1, and there were 103 cases (34.1%) with the current residency address in Zhengzhou City, 193 cases (63.9%) with the current residency address in other cities of Henan Province and 6 cases (2.0%) in other provinces of China. There were 271 cases (89.7%) seeking initial diagnosis in medical institutions, and the diagnostic accuracy of malaria was 56.6% (171/302) at initial diagnosis institutions. A total of 122 cases (40.4%) sought medical care on the day of malaria onset, and 252 cases (86.4%) within 3 days; however, only 22 cases (7.3%) were definitively diagnosed on the day of onset, and 162 cases (53.6%) diagnosed within 3 days. There were no significant differences between malaria cases seeking initial diagnosis at medical institutions and disease control and prevention institutions in terms of the duration from malaria onset to initial diagnosis (Z = -1.663, P > 0.05), from initial diagnosis to definitive diagnosis (Z = -0.413, P > 0.05) or from malaria onset to definitive diagnosis (Z = -0.838, P > 0.05). The median duration (interquartile range) from initial diagnosis to definitive diagnosis of malaria was 3.00 (2.00), 3.00 (6.00), 2.00 (4.00) d and 1.00 (1.00) d among cases seeking medical care at township-level and lower, county-, city- and province-level medical institutions, and the median duration from initial diagnosis to definitive diagnosis of malaria was significantly longer among cases seeking medical care at township-level and lower medical institutions than at city (Z = -3.286, P < 0.008 33) and province-level medical institutions (Z = -9.119, P < 0.008 33), while the median duration from initial diagnosis to definitive diagnosis [1.00 (3.00) d vs. 2.00 (4.00) d; Z = -4.099, P < 0.016] and from malaria onset to definitive diagnosis [3.00 (4.00) d vs. 4.00 (5.00) d; Z = -2.868, P < 0.016] among malaria cases with the current residency address in Zhengzhou City was both shorter than in other cities of Henan Province. The diagnostic accuracy was 89.1% (269/302) among malaria cases in which definitive diagnosis was made, and the accuracy of malaria reexaminations was 94.0% (284/302) in Zhengzhou Municipal Malaria Diagnosis Reference Laboratory.

CONCLUSIONS

P. falciparum malaria was predominant among reported imported malaria cases in Zhengzhou City from 2016 to 2020, and these imported malaria cases were predominantly diagnosed at medical institutions; however, the diagnostic capability of malaria is poor in township-level and lower medical institutions. Strengthening the collaboration between medical institutions and disease control and prevention institutions and improving the diagnostic capability building at medical institutions are recommended to consolidate malaria elimination achivements.

[Epidemic process and influencing factors of hemorrhagic fever with renal syndrome: a review]

Hemorrhagic fever with renal syndrome (HFRS) is a category B infectious disease caused by hantaviruses that cause acute kidney injury and has a high mortality rate, and HFRS control has been given a high priority in China. It has been found that hantavirus types are closely associated with selective host transformation and regional adaption, and continue to evolve in the form of gene recombination. The severity of HFRS varies in hantavirus types. In addition, global environmental changes and alteration of host animal behaviors accelerate Hantavirus genome variations, and large-scale land reclamation and infrastructure building increases the likelihood of human contacts with hosts and disease-transmitting vectors, thereby increasing the risk of HFRS development. This review summarizes the main characteristics and influencing factors pertaining to the epidemic process of HFRS, so as to provide insights into effective prevention and control of this infectious disease.

[Epidemiological characteristics of imported Plasmodium ovale malaria in Jiangsu Province from 2012 to 2020]

OBJECTIVE

To analyze the epidemiological characteristics of imported cases with Plasmodium ovale infections in Jiangsu Province from 2012 to 2020, so as to provide insights into the development of the imported malaria control strategy in the province.

METHODS

All data pertaining to cases with definitive diagnosis of P. ovale malaria in Jiangsu Province from 2012 to 2020 were captured from the National Notifiable Disease Report System and the Information Management System for Parasitic Disease Control in China, including the date of going abroad and returning to China, time of malaria infections overseas, date of malaria onset, initial diagnosis and definitive diagnosis. All data pertaining to epidemic status were descriptively analyzed.

RESULTS

A total of 347 cases of P. ovale malaria were reported in Jiangsu Province from 2012 to 2020, with the highest number seen in 2015 (71 cases). All cases were laboratory-confirmed overseas imported malaria cases, accounting for 14.32% of all reported malaria cases in Jiangsu Province during the period from 2012 to 2020. The 5 cities with the highest number of imported P. ovale malaria cases included Lianyungang City (53 cases, 15.27%), Nantong City (44 cases, 12.68%), Huai'an (44 cases, 12.68%), Taizhou City (44 cases, 12.68%) and Yangzhou City (36 cases, 10.37%). The highest number of imported P. ovale malaria cases was reported in October (39 cases, 11.24%), and the lowest number was seen in December (21 cases, 6.05%). P. ovale infections mainly occurred in were Equatorial Guinea (97 cases, 37.95%), Angola (60 cases, 17.29%) and Nigeria (40 cases, 11.53%). The median duration between returning to China and malaria onset was 64 (144) days, and 7.49% (26/347) of all cases developed malaria one year after returning to China. The initial diagnosis of P. ovale malaria was mainly made at county-level medical institutions (117 cases, 33.72%), and the definitive diagnosis was mainly made at city-level medical institutions (122 cases, 35.16%). The correct rate of initial diagnosis of P. ovale malaria increased from 0 in 2012 to 78.26% in 2020, appearing a tendency towards a rise year by year (χ² = 50.90, P < 0.01).

CONCLUSIONS

Imported P. ovale malaria cases were reported in Jiangsu Province each year from 2012 to 2020, and P. ovale infections predominantly occurred in Africa. Initial and definitive diagnoses of P. ovale malaria were mainly made at city- and county-level medical institutions. Training on the detection ability of malaria parasites is recommended among grassroots microscopists to improve the diagnostic ability of P. ovale malaria, and consolidate the achievements of malaria elimination in Jiangsu Province.

[Analysis on epidemiological characteristics of current advanced schistosomiasis cases in China based on the Epidemiological Dynamic Data Collection Platform (EDDC)]

OBJECTIVE

To investigate the epidemiological characteristics of current advanced schistosomiasis cases in China, so as to provide the scientific evidence for the precision management and medical care of advanced schistosomiasis.

METHODS

The baseline data pertaining to the current advanced schistosomiasis cases in China were collected from the Epidemiological Dynamic Data Collection Platform (EDDC) operated by the Chinese Center for Disease Control and Prevention. The demographic characteristics, population and regional distribution and medical care of advanced schistosomiasis cases were analyzed with a descriptive method.

RESULTS

A total of 31 889 cases with advanced schistosomiasis were reported in China by the end of June, 2019, and these cases were mainly identified in Hubei Province (7 737 cases) followed by in Jiangxi Province (7 256 cases), Hunan Province (5 615 cases), Anhui Province (5 236 cases) and Jiangsu Province (2 908 cases), accounting for 90.2% (28 752/31 889) of total cases in China. The current advanced schistosomiasis cases had a male/female ratio of 1.5∶1, and a mean age of (67.0 ± 11.2) years, with 92.6% (29 521/31 889) detected in individuals at ages of over 50 years. There were 97.6% (31 109/31 889) of the cases with an educational level of junior high school and lower, and 95.2% (30 359/31 889) with an occupation of farmers. Ascites (72.6%, 23 164/31 889) and splenomegaly types (26.3%, 8 386/31 889) were predominant in current advanced schistosomiasis cases in China, and there was a significant difference in the constituent ratio of disease types among current advanced schistosomiasis cases with different age groups (χ² = 362.31, P < 0.01), with the ascites type as the predominant type of advanced schistosomiasis. Among the current advanced schistosomiasis cases, 88.9% (28 358/31 889) and 18.7% (5 973/31 889) had received medical treatment and surgical treatment, respectively.

CONCLUSIONS

The current advanced schistosomiasis cases are predominantly reported in five marshland and lake endemic provinces of China where schistosomiasis is not eliminated, and are mostly categorized as the ascites and megalosplenia types, with minor differences seen in gender and disease-type distributions. Precision medical care should be reinforced according to the epidemiological features of the current advanced schistosomiasis cases, and early screening and standard management and follow-up is required.

Characteristics of human papillomavirus infection among women with cervical cytological abnormalities in the Zhoupu District, Shanghai City, China, 2014-2019

Background

Human papillomavirus (HPV) infection is currently the main cause of cervical cancer and precancerous lesions in female patients. By analyzing 6-year patient data from Shanghai Zhoupu Hospital in China, we retrospectively analyzed the epidemiological characteristics of women to determine the relationship between HPV genotype and cytological test results.

Methods

From 2014 to 2019, 23,724 cases of cervical shedding were collected from Zhoupu Hospital in Shanghai, China. By comparing the results of HPV and ThinPrep cytology test (TCT), the HPV infection rate of patients was retrospectively analyzed. HPV genotyping using commercial kits can detect 21 HPV subtypes (15 high-risk and 6 low-risk). According to the definition of the Bethesda system, seven types of cervical cytology results were involved.

Results

3816 among 23,724 women, nearly 16.08%, were infected with HPV. The top three highest HPV prevalence rates were high-risk type infection, including HPV52 (3.19%), 58 (2.47%) and 16 (2.34%). The number of single-type HPV infections (3480 (91.20%)) was much larger than the number of multi-type ones (336 (8.8%)). Single-type infections were mainly in women aged 50–60 (16.63%) and women under 30 (15.37%), while multi-type infections were more common in women over 60 (2.67%). By analyzing the long-term trends, between 2014 and 2019, HPV52, 58, and 16 subtypes changed significantly, and the HPV positive rate also changed significantly during this period. Among 4502 TCT positive women, 15 (4.04%), 125 (2.64%),159 (1.54%), 4202 (17.71%) and 1 (0.004%) had atypical glandular cells (AGC), high-grade squamous intraepithelial lesions (HSIL), low-grade squamous intraepithelial lesions (LSIL), atypical squamous cells (ASC)and cervical adenocarcinoma, respectively. The HPV infection rates were 66.08%, 63.99%, 115.20%, 119.50%, and 31.72% for NILM, AGCs, HSILs LSILs and ASCs, respectively.

Conclusions

HPV and TCT screening were very important steps in the secondary prevention of cervical cancer. Through the tracking and analysis of HPV and TCT results in this study, it can provide valuable information for Shanghai's HPV screening and prevention strategies, and provide references for clinical decision-making in the treatment of cervical cancer and precancerous lesions.

A systematic review of asymptomatic infections with COVID-19

Since the outbreak of coronavirus disease 2019 (COVID-19) in late December 2019, it has brought significant harm and challenges to over 200 countries and regions around the world. However, there is increasing evidence that many patients with COVID-19 are asymptomatic or have only mild symptoms, but they are able to transmit the virus to others. There are difficulties in screening for asymptomatic infections, which makes it more difficult for national prevention and control of this epidemic. This article reviews the characteristics, treatment, and outcomes of asymptomatic infections with COVID-19, hoping it would be helpful for early prevention and control of this severe public health threat worldwide.

[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.

The epidemiological characteristics of deaths with COVID-19 in the early stage of epidemic in Wuhan, China

OBJECTIVES

To analyze the epidemiological characteristics of COVID-19 related deaths in Wuhan, China and comprehend the changing trends of this epidemic along with analyzing the prevention and control measures in Wuhan.

METHODS

Through the China's Infectious Disease Information System, we collected information about COVID-19 associated deaths from December 15, 2019 to February 24, 2020 in Wuhan. We analyzed the patient's demographic characteristics, drew epidemiological curve and made geographic distribution maps of the death toll in each district over time, etc. ArcGIS was used to plot the numbers of daily deaths on maps. Statistical analyses were performed using SPSS and @Risk software.

RESULTS

As of February 24, 2020, a total of 1833 deaths were included. Among the deaths with COVID-19, mild type accounted for the most (37.2%), followed by severe type (30.1%). The median age was 70.0 (inter quartile range: 63.0-79.0) years. Most of the deaths were distributed in 50-89 age group, whereas no deaths occurred in 0-9 age group. Additionally, the male to female ratio was 1.95:1. A total of 65.7% of the deaths in Wuhan combined with underlying diseases, and was more pronounced among males. Most of the underlying diseases included hypertension, diabetes and cardiovascular diseases. The peak of daily deaths appeared on February 14 and then declined. The median interval from symptom onset to diagnosis was 10.0 (6.0-14.0) days; the interval from onset to diagnosis gradually shortened. The median intervals from diagnosis to death and symptom onset to deaths were 6.0 (2.0-11.0), 17.0 (12.0-22.0) days, respectively. Most of the disease was centralized in central urban area with highest death rate in Jianghan District.

CONCLUSION

COVID-19 poses a greater threat to the elderly people and men with more devastating effects, particularly in the presence of underlying diseases. The geographical distributions show that the epidemic in the central area of Wuhan is more serious than that in the surrounding areas. Analysis of deaths as of February 24 indicates that a tremendous improvement of COVID-19 epidemic in Wuhan has achieved by effective control measures taken by Wuhan Government.

[Epidemiological characteristics of COVID-19 in Wuchang district of Wuhan]

Objective: To analyzes epidemiological characteristics of COVID-19 and provide evidence for adjustment for COVID-19 prevention and control strategies. Methods: The data of COVID-19 cases in Wuchang district reported as of 19 March, 2020 were obtained from National Notifiable Disease Report System of Chinese Disease Prevention and Control Information System. The software's of Excel 2010, SPSSS 22.0, Arc GIS10.2 and Joinpoint regression program 4.8.0.0 were used for statistical analysis. Results: A total of 7547 COVID-19 cases had been reported as of 19 March, 2020 in Wuchang district, including 5 448 confirmed cases (72.19%), 2009 clinical diagnosed cases (26.62%) and 90 asymptomatic cases case (1.19%). The age of the cases was (56.65±16.25) years and age ranged from 2 days to 105 years among confirmed cases, 2634 were males (48.35%) and 2814 were females (51.65%), 2 492 were retirees (45.74%). A total of 545 health workers were infected with SARS-CoV-2 (7.22% of all cases) including 365 confirmed cases and 5 cases have died. A total of 430 cases of death were reported with case fatality rate of 7.89% (430/5 448), case fatality rate of males (10.9%, 266/2 634) was higher than that of females (5.82%, 164/2 814). The first phase of epidemic peak was from January 24 to January 26, the second phase of epidemic peak was from February 1 to February 5 and there was no one of new confirmed case in one day for the first time on March 18. The first four Streets with the highest incidence rates of confirmed cases were Huanghelou Street (1 043.77/100 000), Ziyang Street (627.97/100 000), Yangyuan Street (503.67/100 000) and Shuiguohu Street (486.02/100 000). Compared with females, aged ≤50 years and mild cases of clinical classification respectively, males (RR=0.690, 95%CI: 0.322-1.478), aged >50 years (RR=11.745, 95%CI: 6.878-20.058), severe cases (RR=2.317, 95%CI: 1.789-3.000) and critical cases of clinical classification (RR=10.794, 95%CI: 7.997-14.569), and gender time-dependent covariate (RR=1.392, 95%CI: 1.053-1.840) were major influencing factors of prognosis of COVID-19 confirmed cases. Conclusions: The gender, ages and occupation of distribution were wide among COVID-19 cases in Wuchang district. Males, aged >50 years, severe cases and critical cases of clinical classification were influencing factors of prognosis of COVID-19 confirmed cases. The standardized management of discharged cases, asymptomatic infected cases and close contact persons were main measures to reduce incidence rates of COVID-19 cases.

[Epidemiological characteristics of asymptomatic infection cases of COVID-19 in Guangdong province]

Objective: To analyze the epidemiological characteristics of the cases firstly reported as "asymptomatic infection of COVID-19" in Guangdong province. Methods: The follow-up observation method was used to continuously track and observe the cases firstly reported as "asymptomatic patients with COVID-19" in Guangdong province from January 14 to March 31, 2020. The epidemiological data of the cases were collected to analyze their epidemiological characteristics, outcome and influencing factors. Results: From January 14 to March 31, 2020, a total of 325 cases were firstly reported as "asymptomatic infections of COVID-19" in Guangdong province. The epidemic curve of asymptomatic infection cases was similar to that of confirmed cases, and it had two peaks. The first peak was from January 27 to February 5, and the second peak was from March 17 to March 26. Of the 325 cases, 184 (56.6%) were subsequently converted to confirmed cases. These cases were defined as incubation period asymptomatic infection cases. The age median of the cases was 40 years, and 93.5% (172/184) of the cases showed symptoms within 3 days after the first positive nucleic acid tests were conducted, and 141 (43.4%) of the 325 cases remained asymptomatic status until they were cured and discharged. They were inapparent infection cases, accounting for 8.6% (141/1 642) of those diagnosed with COVID-19 in Guangdong province during the same period. The age median of inapparent infection cases was 27 years. The median of the interval between the first positive nucleic acid test and discharge was 14 days. Up to 90.8% (138/141) of the inapparent infection cases were discharged for centralized medical observation within 28 days. The longest interval between the first positive nucleic acid test and the last positive nucleic acid test was 73 days. The positive rate of nucleic acid test was 0.3% in close contacts of inapparent infection cases and 2.2% in close contacts of incubation period asymptomatic infection cases. There were significant differences in age distribution and source of infection between incubation period asymptomatic infection cases and inapparent infection cases (P<0.05). Old age was the risk factor for the conversion of firstly reported asymptomatic infection cases to confirmed cases. Compared with the 0-19-year-old group, The patients aged 40-59 years and 60 years and above were more likely to become confirmed cases. The OR (95%CI) values were 2.730 (1.380-5.402) and 5.302 (2.199-12.783), and P values were 0.004 and 0.000, respectively. People being infected in China were more likely to become confirmed cases (OR=7.121, P=0.000). Conclusions: There were asymptomatic infection cases among patients diagnosed with COVID-19. The infectiousness of incubation period asymptomatic infection cases might be stronger than that of inapparent infection cases. The proportion of younger cases among asymptomatic infection cases was higher than that of the confirmed cases. Old age and domestic infection were the risk factors for the conversion of asymptomatic infection cases to confirmed cases, to which more attention should be paid. Further serological investigations are needed to provide a basis for the development of COVID-19 prevention and control strategies.

[Epidemiological characteristics of dengue fever outbreaks in China, 2015-2018]

Objective: To analyze the epidemiological characteristics of outbreaks of dengue fever in China from 2015 to 2018, and provide evidence for the prevention and control of dengue fever. Methods: We extracted the incidence data of dengue fever from China Disease Prevention and Control Information System, Public Health Emergency Reporting Management Information System and Vector Biological Monitoring System, and explored the epidemiological characteristics of the outbreaks in the past four years. Excel 2010 software and SPSS 20.0 software were used for data processing and analysis, ArcGIS 10.5 software was used for mapping. Results: A total of 111 outbreaks of dengue fever were reported nationwide from 2015 to 2018, involving 12 490 cases, accounting for 73.7% of the total cases in China. These outbreaks occurred in 85 counties and districts of 4 provinces, namely Guangdong (77 outbreaks), Yunnan (14 outbreaks), Zhejiang (8 outbreaks) and Fujian (8 outbreaks). The outbreaks occurred during May-November. Small-scale outbreaks with no more than 10 cases ended within 30 days (28/34, 82.4%) and larger-scale outbreaks lasted for several months. Dengue virus type 1 and type 2 were the main epidemic pathogens of dengue fever outbreaks in China. The outbreaks mainly occurred in areas with high population density and poor sanitary environment. There were significant differences in the age and occupational composition of the cases in the main outbreak provinces. Conclusions: Outbreaks of dengue fever can been seen in more areas in China, even in high latitudes areas. The epidemiologic characteristics of the outbreaks were different among provinces, showing as port type, rural type and urban type. Each province should adjust the control strategies accordingly.

[Epidemiological characteristics of COVID-19 in Shaanxi province]

Objective: To understand the incidence trend and epidemiological characteristics of COVID-19 in Shaanxi province. Methods: The incidence data of COVID-19 reported in Shaanxi as of 22 February, 2020 were collected for an epidemiological descriptive analysis. Results: A total of 245 confirmed cases of COVID-19 were reported in Shaanxi. Most cases were mild (87.76%). As time passed, the areas where confirmed cases were reported continued to increase. The case number in Xi'an was highest, accounting for nearly half of the total reported cases in the province. The epidemic pattern in Shaanxi had gradually shifted from imported case pattern to local case pattern, and the transmission of local cases was mainly based on family cluster transmission. The confirmed cases from different sources had caused the secondary transmission in Shaanxi. After February 7, the number of reported cases began to fluctuate and decrease stably, indicating a decrease-to-zero period. Conclusions: At present, the overall epidemic of COVID-19 in Shaanxi has gradually been mitigated. However, considering the approaching of return to work and study and the increasing of imported cases from other countries, the prevention and control of COVIS-19 in Shaanxi will face new challenges.

[Epidemiological characteristics of COVID-19 in Gansu province]

Objective: To understand the epidemiological characteristics of COVID-19 cases in different epidemic stages in Gansu province. Methods: Epidemiological investigation was conducted to collect the information of confirmed COVID-19 cases, including demographic, epidemiological and clinical information. Results: As of 25 February 2020, a total of 91 confirmed COVID-19 cases had been reported in Gansu. The epidemic of COVID-19 in Gansu can be divided as three different stages, i.e. imported case stage, imported-case plus indigenous case stage, and indigenous case stage. A total of 63 cases were clustered cases (69.23%), 3 cases were medical staff infected with non-occupational exposure. The initial symptoms included fever (54.95%, 50/91), cough (52.75%, 48/91), or fatigue (28.57%, 26/91), the proportion of each symptom showed a decreasing trend along with the three epidemic stages, but only the differences in proportions of fever (trend χ2=2.20, P<0.05) and fatigue (trend χ2=3.18, P<0.05) among the three epidemic stages were statistically significant. The cases with critical severe symptoms accounted for 42.85% (6/14), 23.73% (14/59) and 16.67% (3/18), respectively, in three epidemic stages, showed a decreasing trend (H=6.45, P<0.05). Also, the incubation period prolonged along with the epidemic stage (F=51.65, P<0.01), but the intervals between disease onset and hospital visit (F=5.32, P<0.01), disease onset and diagnosis (F=5.25, P<0.01) became shorter along with the epidemic stage. Additionally, the basic reproduction number (R0) had decreased from 2.61 in imported case stage to 0.66 in indigenous case stage. Conclusions: The COVID-19 epidemic in Gansu was caused by the imported cases, and about 2/3 cases were clustered ones. No medical worker was observed to be infected by occupational exposure. With the progression of COVID-19 epidemic in Gansu, the change in initial symptom and incubation period suggests, the early screening cannot only depend on body temperature monitoring.

[Correlation analysis on meteorological factors regarding the incidence of hand, foot and mouth disease in Xinjiang Uygur Autonomous Region, 2011-2018]

Objective: To study the correlation between meteorological factors and the incidence of hand, foot and mouth disease (HFMD) in Xinjiang Uygur Autonomous Region (Xinjiang) so as to provide scientific evidence for the early warning, prediction, prevention and control of HFMD. Methods: Data on HFMD surveillance and related population was collected from the China Information System for Disease Control and Prevention from 2011 to 2018. Meteorological data was obtained from http://www.tianqihoubao.com. Correlation analysis on meteorological factors and the incidence of HFMD in Xinjiang was conducted, using the Excel 2007, SPSS 17.0, and Spatial Distribution Map by ArcGIS 10.2 software. Results: HFMD usually occurred between April and July. Numbers of patients reached the top in May and June. Temperature was positively correlated with the incidence of HFMD (r=0.370, P<0.01) while precipitation was positively correlated with the incidence of HFMD (r=0.747, P<0.01). The temperature threshold appeared as 5 ℃-35 ℃ for the incidence of HFMD. Interval period was one month between the peak of both the incidence of HFMD and the precipitation. A power function relationship (y=0.009 4x(2.332 9), R(2)=0.898 9) was noticed between the precipitation and the incidence of HFMD. Conclusions: The incidence of HFMD was closely related to the meteorological factors including temperature and precipitation in Xinjiang during 2011-2018. Our findings have provided evidence for the development of early warning system on HFMD in Xinjiang.

[Analysis of imported malaria cases in Leshan City from 2012 to 2018]

OBJECTIVE

To analyze the epidemiological characteristics of reported malaria cases in Leshan City, so as to provide insights into malaria control.

METHODS

The data pertaining to malaria cases and epidemiological individual information in Leshan City from 2012 to 2018 were captured from the National Notifiable Communicable Disease Reporting System and the Information System for Parasitic Diseases Control and Prevention, and a descriptive epidemiological analysis was performed.

RESULTS

A total of 34 malaria cases were reported in Leshan City from 2012 to 2018, and all cases were confirmed as imported malaria cases by Sichuan provincial malaria diagnosis reference laboratory. Of all 34 cases, there were 14 vivax malaria cases, 18 falciparum malaria cases, a malariae malaria case and an ovale malaria case. The sites where malaria parasite infections occurred mainly included African areas (accounting for 58.82%) and Southeastern Asian areas (accounting for 29.41%), and the malaria cases were mainly reported in January, February, June and July, which accounted for 65.63% of all cases. The cases included 33 men and a woman, and had ages of 21 to 59 years. The cases'occupations mainly involved overseas peasants, technical workers and businessmen. The duration from onset of malaria to diagnosis ranged from 0 to 31 days, and the percentage of definitive diagnosis was 85.29% at initial diagnosis.

CONCLUSIONS

There are no local malaria cases in Leshan City; however, imported malaria cases are reported. The monitoring, management and health education of overseas returners should be further strengthened and malaria training should be improved to enhance the diagnostic and treatment capability in professionals, so as to consolidate malaria control achievements.

[Genotype and evolution of hantavirus in Tiantai of Zhejiang province, 2011-2018]

Objective: By investigating the genotype and evolutionary variation of hantavirus (HV) in Tiantai county, a national surveillance site for hemorrhagic fever with renal syndrome (HFRS) was set in Zhejiang province, from 2011 to 2018, to reveal the molecular epidemiological characteristics of hantavirus (HV) in Tiantai. Methods: Total RNA was extracted from ultrasound treated HV antigen- positive rat lung samples in Tiantai from 2011 to 2018. After cDNA was prepared, nested PCR was used to amplify partial sequence of M fragments by using specific primers of HV. The sequences of HV in Tiantai from 2011 to 2018 were compared with other known HV sequences in order to identify the genotype and analyze the evolution and variation of the virus. Results: In 67 HV antigen-positive lung specimens, 31 were positive in nested PCR amplification with type-specific primers, including 30 Hantaan virus (HTNV) positive samples, 1 Seoul virus (SEOV) positive sample, and all the 31 samples were from Apodemus agrarius. The phylogenetic tree based on partial M segment was divided into monophyletic group, 30 strains were distributed in HTNV group and 1 was in SEOV group. The HTNV strain Tiantai T2018-130 was independently in one branch, sharing 84.8%-87.9% homology with other strains both at home and abroad, including 29 strains in HTNV group in Tiantai. The other 29 HTNV strains in Tiantai showed closer relationship. The SEOV strain T2016-31 from Apodemus agrarius showed closer relationship with previous strains of SEOV, Tiantai ZT71, ZT10 and Z37 strains of Wenzhou, Zhejiang province. Conclusions: HTNV, the main genotype of HV in Tiantai of Zhejiang province, showed obvious geographic clustering, but the strain T2018-130 was distinct from the others in Tiantai. Meanwhile, by sequence analysis, we confirmed that The SEOV strain T2016-31 existed in in Apodemus agrarius, indicating there was a phenomenon of "spillover" between virus and host in SEOV evolution.

[Epidemiological characteristics of imported malaria in Chenzhou City, Hunan Province from 2010 to 2017]

OBJECTIVE

To study the epidemiological characteristics of imported malaria in Chenzhou City, Hunan Province, so as to provide the reference for consolidating the malaria elimination and formulating the prevention and control strategies of imported malaria.

METHODS

The epidemiological characteristics of imported malaria were statistically analyzed in Chenzhou City from 2010 to 2017.

RESULTS

Totally 46 malaria cases, which were all imported, were reported in Chenzhou City from 2010 to 2017, with an average annual incidence of 0.12/10⁵. The reported malaria cases were mainly falciparum malaria, accounting for 60.87% of the total number of cases. There was no obvious seasonal distribution of malaria cases, but the top of reported cases were in June. Totally 73.91% of malaria cases were concentrated in Beihu District, Suxian District, Guiyang County and Zixing City. These cases were mainly the young and middle-aged and 69.57% of the cases were from 36 to 60 years old. There was a statistically significant difference in the distribution of malaria patients among the age groups (χ² = 47.80, P < 0.01). The median time from onset to diagnosis was 6 days, and the case confirmed institutions were dominated by municipal and above medical institutions, accounting for 52.17% of the total number of cases. There was a statistically significant difference in the proportion of confirmed cases among medical and health institutions at all levels ( χ² = 41.96, P < 0.01).

CONCLUSIONS

The importation of malaria in Chenzhou City is still severe. The awareness of malaria diagnosis and treatment in primary medical institutions, malaria patients' serum tests, and the health education of malaria control and prevention knowledge should be strengthened to consolidate the malaria elimination results.

[Analysis of schistosomiasis cases report in National Notifiable Disease Report System in China, 2015-2017]

OBJECTIVE

To understand the reporting situation of schistosomiasis cases in National Notifiable Disease Report System (NNDRS) in China from 2015 to 2017, and to seek current deficiencies on case reporting as well as to analyze the epidemiological characteristics of schistosomiasis cases.

METHODS

The data of schistosomiasis cases in China from 2015 to 2017 were collected from NNDRS, and the reporting situation and epidemiological characteristics of schistosomiasis cases were analyzed.

RESULTS

From 2015 to 2017, totally 59 981 schistosomiasis cases were reported in China, among which, 1 460 cases were deleted, and 58 521 were censored cases. The statistics and analysis showed that a part of the case reporting had been carried out in nonstandard ways, mainly involving the random deletion of cases, reporting time not compliance with regulations, incorrect classification, and severe omission of cases. Among the 58 521 censored cases, the sex ratio of the male to the female was 1.83∶1, the average age of the cases was (51.91 ± 11.30) years, and farmers and fishermen accounted for 93.26% (54 577 cases) and 3.46% (2 022 cases), respectively. The reported cases mainly concentrated in Anhui, Hunan, Hubei and Jiangxi provinces, accounting for 99.73% of the total number in China. During this period, Beijing, Zhejiang and other provinces (cities and regions) reported 11 imported schistosomiasis cases, all of them were schistosomiasis mansoni cases or schistosomiasis haematobia cases.

CONCLUSIONS

From 2015 to 2017, the reported cases of schistosomiasis are mainly clinically diagnosed cases. Compared with the annual report of the national schistosomiasis control, the number of confirmed cases in NNDRS is seriously missed. Therefore, the endemic provinces should strengthen the supervision on confirmed cases and reporting quality of schistosomiasis cases in accordance with the relevant law and regulation.

[Epidemiological characteristics of outbreaks of norovirus-GⅡ.2, GⅡ.17 and GⅡ.4/Sydney in Guangdong province, 2013-2017]

Objective: To understand the epidemiologic characteristics of outbreaks, caused by norovirus-GⅡ.2、GⅡ.17 and GⅡ.4/Sydney in Guangdong Province from 2013 to 2017 and to provide scientific evidence for epidemic prevention and control. Methods: Incidence data of norovirus outbreaks in Guangdong from January 1(st) 2013 to November 30(th) 2017 were collected from Public Health Emergency Management Information System. RT-PCR was performed for every case of each outbreak to detect norovirus nucleic acid and gene sequencing was conducted to identify the genotype of norovirus. Characteristics of norovirus GⅡ.2, GⅡ.17 and GⅡ.4/Sydney outbreaks were analyzed. Directly standardized method was used to calculate the proportion of symtoms as diarrhea and vomitting. Results: From January 1(st) 2013 to November 30(th) 2017, a total of 167 norovirus outbreaks were reported in Guangdong, and 115 outbreaks were caused by norovirus GⅡ.2, GⅡ.17 and GⅡ.4/Sydney respectively. The outbreaks caused by norovirus GⅡ.2 accounted for 39.68% (25/63) in primary schools, 28.57% (18/63) in child care settings, 25.40% (16/63) in middle schools and 6.35% (4/63) in universities. Outbreaks caused by norovirus GⅡ.17 accounted for 41.03% (16/39) in middle schools, 20.51% (8/39) at workplaces, 15.38% (6/39) in primary schools, 12.82% (5/39) in universities, 5.13% (2/39) in communities and child care settings respectively. The outbreaks caused by norovirus GⅡ.4/Sydney accounted for 53.85% (7/13) in universities, 15.38% (2/13) in child care settings and at workplaces respectively, 7.69%(1/13) in primary schools and middle schools respectively. The outbreaks caused by norovirus GⅡ.2 had 77.78% (49/63) of contact transmission, 17.46% (11/63) of food-borne transmission. The outbreaks caused by norovirus GⅡ.17 showed 53.85% (21/39) of food-borne transmission, 15.38% (6/39) of contract transmission, 12.82% (5/39) of water-borne transmission. The outbreaks caused by norovirus GⅡ.4/Sydney had 53.85% (7/13) of food-borne transmission, 38.46% (5/13) of the contact transmission. In terms of the clinical manifestations, the standardized proportion of vomit was 73.76% and the proportion of diarrhea was 42.85% in cases infected with norovirus GⅡ.2, the proportion of standardized of vomit was 76.37% and the proportion of diarrhea was 51.40% in cases infected with norovirus GⅡ.17, with the standardized proportion of vomit was 54.10% and the proportion of diarrhea was 55.95% in cases infected with norovirus GⅡ.4/Sydney. Conclusions: The outbreaks caused by norovirus GⅡ.2 through contact transmission mainly occurred in primary schools, child care settings and middle schools. The outbreaks caused by norovirus GⅡ.17 through food-borne transmission mainly occurred in middle schools and at workplaces. The outbreaks caused by norovirus GⅡ.4/Sydney food-borne transmission and contact mainly occurred in universities.

[Systematic review on the characteristics of acute gastroenteritis outbreaks caused by sapovirus]

Objective: To understand the epidemiological and etiological characteristics of outbreaks on acute gastroenteritis caused by sapovirus (SaV) worldwide. Methods: Literature about the outbreaks on acute gastroenteritis caused by SaV were retrieved from the databases including WanFang, CNKI, PubMed and Web of Science after evaluation. Time, geography, setting and population distributions of outbreaks, transmission mode, SaV genotype and clinical characteristics of the patients were analyzed. Results: A total of 34 papers about SaV were included, involving 146 outbreaks occurred between October 1976 and April 2016. In these papers, 138 outbreaks were reported on the related months. All these outbreaks occurred in northern hemisphere. SaV outbreaks occurred all year around, but mainly in cold season, the incidence was highest in December (25 outbreaks) and lowest in in August (2 outbreaks). Most outbreaks were reported by Japan, followed by Canada, the United States of America and the Netherlands. There were 141 outbreaks for which the occurring settings were reported, child-care settings were most commonly reported setting (48/141, 34.04%), followed by long-term care facility (41/141, 29.08%) and hospital (16/141, 11.35%). Clinical symptoms of 1 704 cases in 31 outbreaks were reported, with the most common symptom was diarrhea (1 331/1 704, 78.12%), followed by nausea (829/1 198, 69.20%), abdominal pain (840/1 328, 63.25%), vomiting (824/1 704, 48.36%) and fever (529/1 531, 34.53%). Genotypes of SaV were determined for 119 outbreaks. GⅠ(51/119, 42.86%) and GⅣ (45/119, 37.82%) were predominant. The outbreaks of GⅣ SaV increased suddenly in 2007, and the outbreaks of GⅠ SaV mainly occurred in 2008 and during 2011-2013. Conclusions: SaV outbreaks were reported mainly by developed countries, with most outbreaks occurred in cold season, in child-care settings and long term care facility. GⅠ and GⅣ were the most common genotypes of SaV. Prevention and control of SaV outbreak in China seemed relatively weak, and it is necessary to conduct related training and to strengthen the SaV outbreak surveillance in areas where service is in need.

[Epidemiological and pathogenic characteristics of mumps in Fujian province, 2005-2017]

Objective: To understand the epidemiological and etiological characteristics of mumps in Fujian province, 2005-2017. Methods: All the reported mumps cases were collected through the National Notifiable Disease Information Management System, 2005-2017. Active search and interviews were conducted to collect the information on vaccination of mumps. Throat swab specimens were collected for cells culture, genotyping and gene sequence analysis on mumps virus (MuV). Results: A total of 83 959 cases of mumps were reported in Fujian province from 2005 to 2017, with an average annual incidence of 17.6 per 100 000. Since 2007, the incidence appeared increasing but then decreasing, reaching the lowest level (7.5 per 100 000), after the setup of a monitoring program. Annually, the onset time of mumps showed an obvious two seasonal peaks, one from April to July, with a weakening trend, and the other from October to January with a rising trend. Most of the mumps cases occurred among students, kindergarten and scattered children (89.2%, 5 814/6 517), children aged 5-9 years (38.8%, 2 527/6 517), with cases reported from every region. Program from the pathogen surveillance showed that the transmission chain of G genotype mumps virus did exist in Fujian. Data from the sequence analysis revealed that mutations in the nucleotide of G genotype strain in 2015 had led to mutation of 6 amino acid sites in the SH gene coding region, resulting in the differences appearing in both nucleotide and amino acid homology with type A vaccine strain. Conclusions: The incidence of mumps decreased annually, in Fujian. Prevention programs should focus on primary and secondary school students. In Fujian province, we also noticed the transmission chain of mumps G genotype with some amino acid mutations in the SH gene coding region. Monitor programs on both epidemiologic and etiology, should be strengthened.

[Epidemic status of malaria in Zhenjiang City from 2004 to 2017]

OBJECTIVE

To analyze the epidemic situation and epidemiological characteristics of malaria in Zhenjiang City from 2004 to 2017, so as to provide the evidence for formulating the reasonable strategies and measures for malaria prevention and control.

METHODS

The epidemiological data of malaria in Zhenjiang City from 2004 to 2017 were collected and analyzed for the epidemic situation, epidemiological characteristics, species of Plasmodium, blood test status for febrile patients.

RESULTS

A total of 182 malaria cases were reported in Zhenjiang City between 2004 and 2017, 123 cases (67.58%) were infected with P. vivax, and 55 cases (30.22%) were infected with P. falciparum. Among all the reported cases, 41 (22.53%) were local cases, 66 (36.26%) were imported cases from other provinces in China, 75 (41.21%) were imported cases from abroad. Most of the cases were male (133 cases), and 59.89% of them concentrated in the age groups of 20-50 years. These cases were mainly farmers (24.73%, 45/182) and workers (24.18%, 44/182), and most of the cases occurred from July to September. From 2004 to 2017, the blood tests were conducted for 258 879 febrile patients, with a positive detection rate of 0.007% in the local population and 0.724% in floating population, and there was a statistically significant difference between them (P<0.01).

CONCLUSIONS

Since 2011, no indigenous cases have been reported in Zhenjiang City, and therefore, the control of imported malaria from abroad has become the key of malaria prevention and control in this city.

[Epidemiological analysis and control strategy discussion for overseas imported malaria cases reported in Chongqing City from 2011 to 2015]

OBJECTIVE

To analyze the epidemiological characteristics of overseas imported malaria reported in Chongqing City from 2011 to 2015, so as to provide the evidence for improving the imported malaria control strategies.

METHODS

The epidemiological data of overseas imported malaria cases were collected and analyzed descriptively for the species, original countries, diagnosis and treatment in Chongqing City from 2011 to 2015.

RESULTS

A total of 148 overseas imported malaria cases were reported in Chongqing City from 2011 to 2015, in which 96 (65.54%) cases were falciparum malaria, and 37 (24.32%) cases were vivax malaria; 125 (84.46%) cases were infected in Africa, and the rest of 23 (15.54%) cases were infected in Southeast Asia. Most of the patients were 30 to 50 years old male workmen, and the ratio of male to female was 11.42:1. There was no obvious seasonal distribution among the reported timelines of the cases; however, there were two small peaks from June to August and from January to February. The median interval time of imported malaria cases from malaria onset to see a doctor was 1 day and from seeing the doctor to get malaria diagnosis was 2 days. The patients' first selected institutions were county medical institutions (50 cases, 33.78%), then provincial medical institutions (36 cases, 24.325%) and private doctors (20 cases, 13.51%), and only 79 (53.38%) patients got malaria diagnoses in their first selected institutions. The standard treatment were provided to 142 (95.54%) cases. There were 43 (29.05%) patients had serious complications and three patients were dead.

CONCLUSIONS

It is very important to enhance the multi-sector's collaboration to establish the collaborative investigation mechanism for screening malaria patients, and strengthen malaria health education for overseas workers and training courses in primary care medical institutions.

[Epidemiological analysis of imported malaria cases in 20 counties at border region of Yunnan Province from 2012 to 2014]

OBJECTIVE

To analyze the epidemiological characteristics of the imported malaria cases in 20 counties at the border region of Yunnan Province from 2012 to 2014, so as to provide the evidence-based proof for adjusting the strategies in the elimination stage.

METHODS

The malaria epidemic data of the 20 border counties in Yunnan Province from 2012 to 2014 were collected and analyzed by using Microsoft Excel 2010.

RESULTS

From 2012 to 2014, a total of 1 558 malaria cases were reported in the 20 border counties in Yunnan Province, among which, 1 336 were imported cases, accounting for 85.75% (1 336/1 558), and 222 were indigenous cases, accounting for 14.25% (222/1 558). The number of the imported cases in the above years took up 80.00% (544/680), 89.10% (425/477) and 91.52% (367/401) of the total reported cases in the whole year, respectively. Among all the 1 336 imported cases, 1 045 (78.22%) were infected with Plasmodium vivax, 284 (21.26%) were infected with P. falciparum, 3 were infected with P. malariae, 3 were mixed infection and 1 was an unclassified case; 2 patients died. And 95.58% of the cases were mainly infected in Myanmar (1 277 cases). Young and middle-aged adult of 20-40 years who worked overseas were the predominant (802 cases, 60.03%) and most of the cases occurred from April to June of the year (679 cases, 50.82%). Those cases mainly distributed in Tengchong (459 cases), Ruili (366 cases), Yingjiang (191 cases) and Mangshi (78 cases).

CONCLUSIONS

The epidemic situation of imported malaria is serious in the border region of Yunnan Province. Therefore, the surveillance system of malaria control needs to be well planned and managed to ensure timely case detection and prompt response at the elimination and post-elimination stage.

[Epidemiological characteristics of echinococcosis death cases in China from 2008 to 2016]

OBJECTIVE

To understand the epidemiological characteristics of death cases of echinococcosis in China from 2008 to 2016, so as to provide an important reference for the prevention and control of echinococcosis.

METHODS

The death information registration and management system data were selected to analyze the epidemiological characteristics of the death cases of echinococcosis. The data were analyzed by SPSS 21.0 and the map was drawn by ArcGIS 10.1 software.

RESULTS

From 2008 to 2016, a total of 367 death cases of echinococcosis were reported in China, and the number of deaths in turn was 33, 30, 21, 32, 35, 54, 55, and 81 in each year, with an annual average crude mortality of 129.29 /10⁵. The average age of death was (56 ± 18) years; the sex ratio of male to female was 100∶94. There was no statistical difference between the male and female death cases (χ² = 0.33, P > 0.05).The death cases of echinococcosis were mainly distributed in endemic areas of Qinghai, Sichuan, Ningxia, Xinjiang, Gansu, Inner Mongolia, Yunnan and non-endemic areas of Heilongjiang, Jiangsu, Henan and Shandong. The death cases in the first eleven provinces accounted for 87.5% (321/367) of the total death cases, among which the highest proportions of the nationality, occupation, educational level, highest diagnostic units, and the place of death were Han (52.0%, 191/367), farmer (46.6%, 171/367), junior high school or below (57.2%, 210/367), provincial or three-level hospitals (46.6%, 171/367), and at home (59.9%, 220/367).

CONCLUSIONS

Since 2014, the death cases of echinococcosis in China have been increasing year by year, indicating that the prevention and treatment of echinococcosis is still very serious. The causes for the rise of the fatality rate remain to be further studied.

[The effects of closure to live poultry markets on Avian influenza A (H7N9) epidemics in China]

Since March 2013, China had experienced five seasonal epidemics related to Avian influenza A (H7N9). An unprecedented outbreak of H7N9 epidemic started from September 2016, with 730 cases reported till June 30(th) 2017, in mainland China that caused profound influences on both social development and health of the people. As an emerging infectious disease, information on pathogenic characteristics, transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear. Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated, mutated, spread and thus infected the human beings. Hence, closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China. However, the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial. This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies, aiming to provide references for developing a better program on H7N9 control and prevention in the country.

[Epidemiological characteristics of newly reported HIV infections in Chinese and Burmese residents, during 2012-2016 in Dehong Dai and Jingpo Autonomous Prefecture, Yunnan province]

Objective: To understand the epidemiological characteristics of newly reported HIV infections in Chinese and Burmese residents during 2012-2016 in Dehong Dai and Jingpo Autonomous Prefecture of Yunnan province (Dehong) and to provide evidence for the development of related programs on prevention and control. Methods: All the HIV infections who were newly reported during 2012-2016 in Dehong, were recruited as the study subjects, with epidemiological characteristics of the cases analyzed by using the software SPSS 22.0. Results: A total of 5 692 HIV infections were newly reported between 2012 and 2016 (including 5 592 in this study), in which the Chinese patients accounted for 43.3% (2 419) and the rest 56.7% (3 173) were Burmese. Differences in age, gender and other social characteristics of these newly reported HIV infections were statistically significant between the Chinese and the Burmese (all p-values <0.05). Most cases were males and between the age of 20-49 years old. Other characteristics of the patients would include: having had primary school education, married, being farmers, and with CD(4)(+)T cells counts ≥350 cells/μl. HIV infection was mainly transmitted through sexual contact among the Chinese patients but through injecting drug use among the Burmese patients. Conclusions: Epidemiological characteristics of the newly reported HIV infections were different between the Chinese and the Burmese, between 2012 and 2016 in Dehong. Targeted prevention and control programs should be taken.

[Epidemiological characteristics of malaria prevalence in Danyang City from 2004 to 2015]

OBJECTIVE

To analyze the epidemiological characteristics of malaria prevalence in Danyang City from 2004 to 2015, so as to provide the evidence for formulating the strategy of prevention and control of malaria.

METHODS

The data of malaria serum tests, the reported malaria cases from the Internet Reporting System, and the epidemiological case survey from 2004 to 2015 as well as the mosquito monitoring data from 2008 to 2015 were collected and analyzed.

RESULTS

From 2004 to 2015, 58 malaria cases were reported in Danyang City, with an average annual incidence rate of 0.6/10⁵. Among the cases reported, vivax malaria accounted for 65.52% (38/58), falciparum malaria accounted for 5.17% (3/58), oval malaria accounted for 1.72% (1/58), and unclassified subtype accounted for 27.59% (16/58). The local infection cases accounted for 31.03% (18/ 58), and the imported cases accounted for 68.97% (40/58). There were no local infections since 2011. Anopheles sinensis, the only malaria vector in Danyang City, was still prevalent, but its density was low.

CONCLUSIONS

Imported malaria poses a serious threat to the malaria elimination achievements in Danyang City, and the surveillance and disposal of imported malaria need to be strengthened.

[Analysis of epidemiological characteristics of imported malaria cases in Chongqing Municipality in 2015]

OBJECTIVE

To analyze the laboratory diagnosis results and epidemiological characteristics of imported malaria cases in Chongqing Municipality in 2015.

METHODS

According to the Standard Operating Procedures of Malaria Diagnosis Reference Laboratory Manual, all the blood samples collected from the imported malaria patients were detected by microscopy, RDT and nest PCR. Meanwhile, the epidemiological data of the malaria cases were collected from the Parasitic Diseases Information Management System and analyzed.

RESULTS

Totally 31 cases of imported malaria were reported in Chonqing Municipality in 2015, among which, there were 2 vivax malaria cases (6.45%), 23 falciparum malaria cases (74.19%), 5 ovale malaria cases (16.13%), 1 malariae malaria case (3.22%). For the 5 ovale cases, three of them were confirmed as Plasmodium ovale wallikeri infection. Among all the cases, 30 cases (96.77%) were from African countries, 1(3.33%) was from Southeast Asia. Thirty patients were male, and 1 was female. All the patients were aged from 23-61 years. There was no obvious seasonality in the case distribution. Both the medians of duration from malaria attack to first visiting a doctor and from first visiting a doctor to diagnosis were 2 days. The medical care units that the patients first visited were mainly county-level units, while those that made the diagnosis were mainly provincial level institutes.

CONCLUSIONS

All the malaria cases in Chongqing in 2015 are imported, no local cases have been found, which suggests that this municipality still maintain the malaria elimination state. However, the monitoring and management of imported malaria cases as well as the training on malaria control for related medical staff still need to be strengthened.

[Epidemiological analysis of malaria prevalence in Nanjing City from 2010 to 2015]

OBJECTIVE

To analyze the epidemiological characteristics of malaria in Nanjing City, so as to provide the evidence for further formulating and adjusting the malaria prevention and control strategy.

METHODS

The data of malaria situation, malaria cases and epidemiological investigations were collected from the Internet Reporting System in Nanjing City from 2010 to 2015 and analyzed statistically.

RESULTS

A total of 137 confirmed malaria cases were reported in Nanjing City from 2010 to 2015, including 102 falciparum malaria cases (74.45%), 33 vivax malaria cases (24.09%), one ovale malaria case (0.73%) and one quartan malaria case (0.73%). Among the 137 malaria cases, 126 cases (91.97%) were imported from foreign countries, 2 cases (1.46%) were infected locally, and nine cases (6.57%) were imported from other provinces in China. Among the 126 overseas imported cases, 117 cases were imported from African countries and 9 from Asian countries. These malaria cases were majorly young men working as migrant workers, laborers and technical persons. About 19.30% of the cases went to hospital on onset day, and 55.65% were confirmed by medical institutions as malaria in the same day. The majority of diagnosis institutions were municipal hospitals (74.45%).

CONCLUSIONS

The number of malaria cases in Nanjing City is declining year by year. The local infections are eliminating gradually. However, the situation of imported malaria from overseas is still serious. Therefore, the surveillance work and health education still should be strengthened, so as to reduce the risk of imported malaria.

[Analysis of malaria epidemiological characteristics in Hechi City, Guangxi Zhuang Autonomous Region from 2005 to 2015]

OBJECTIVE

To analyze the epidemiological characteristics of malaria in Hechi City, Guangxi Zhuang Autonomous Region from 2005 to 2015, so as to provide the evidence for formulating and adjusting measures of malaria elimination.

METHODS

The data of malaria cases in 11 counties of Hechi City from 2005 to 2015 were collected and analyzed by using Micro-soft Office Excel 2003 and SPSS 17.0.

RESULTS

A total of 160 malaria cases were reported in Hechi City from 2005 to 2015, and the annual average malaria incidence was 3.6 per million. There were 10 local recurrence cases (accounting for 6.25％, 10/160) and 150 imported cases (accounting for 93.75％, 150/160). For the etiology, Plasmodium vivax accounted for 51.87% (83/160) in these cases, P. falciparum accounted for 34.38% (55/160), P. ovale accounted for 1.25% (2/160), P. malariae accounted for 5.00% (8/160), and the indeterminate accounted for 7.50% (12/160). During the period of 11 years, the malaria incidence first dropped and then rose. There were no local cases after 2009. However, an imported falciparum malaria death case was reported in 2010, a severe imported falciparum malaria case was reported in 2013 and another in 2015. A severe case of maternal-neonatal vivax malaria was reported in 2014. These cases were mainly distributed in 10 counties of Hechi City, with more young male adults who engaged in digging mining. More cases concentrated from April to August. Most of the reported malaria cases were imported, 60.00% (96/160) of them returned from Africa and Southeast Asia, and 33.75% (54/160) from other domestic provinces. The median of the interval from symptom appearance to diagnosis was 5 d, and there was a significant difference among the above years (χ²= 33.40, P＜0.05).

CONCLUSIONS

Malaria is still an important public health problem in Hechi City, and the appropriate control measures and effective tools should be strengthened for malaria elimination. The key to consolidate the achievements of malaria control is strengthening the malaria monitoring management of the floating population.

[Epidemiological analysis of imported malaria in Hailing District, Taizhou City from 2010 to 2015]

OBJECTIVE

To investigate the epidemiological characteristics of imported malaria in Hailing District, Taizhou City, so as to provide the evidence for formulating the effective prevention and control strategy.

METHODS

The network reports, questionnaires and epidemic reports of imported malaria cases in Hailing District from 2010 to 2015 were collected and analyzed retrospectively.

RESULTS

From 2010 to 2015, totally 46 cases of imported malaria were reported, including 40 cases of falciparum malaria (86.96%), 4 cases of ovale malaria (8.70%), 1 case of quartan malaria (2.17%) and 1 case of multi-infection of falciparum malaria and tertian malaria (2.17%). No seasonal trend of time of the disease onset was observed. All the patients were return abroad with clear residence histories in malaria epidemic areas. The average time from disease onset to definite diagnosis was 2 d and 8 patients were definitely diagnosed within 24 h. All the 46 patients were cured.

CONCLUSIONS

All the malaria cases reported were imported cases in Hailing District in the last five years. Effective prevention and control measures are the key to the malaria elimination.

The first human infection with severe fever with thrombocytopenia syndrome virus in Shaanxi Province, China

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease discovered in China in 2009. In July 2013, the first human infection with SFTS virus (SFTSV) was detected in Shaanxi Province, Western China.

METHODS

A seroprevalence study among humans was carried out in an SFTS endemic village; specifically, serum samples were collected from 363 farmers in an SFTS endemic village in Shaanxi Province. The presence of SFTSV antibodies in serum was determined using an ELISA.

RESULTS

SFTSV antibodies were found in a total of 20 people (5.51%), with no significant difference between males and females (6.93% and 4.42%, respectively; Chi-square=1.29, p=0.25). Moreover, the SFTSV antibody positive rate was not significantly different across different age groups (Chi-square=2.23, p=0.69).

CONCLUSIONS

SFTSV readily infects humans with outdoor exposure. The results of the serological study indicate that the virus circulates widely in Shaanxi Province. SFTSV represents a public health threat in China.

Epidemiological characteristics of severe fever with thrombocytopenia syndrome in Zhejiang Province, China

OBJECTIVES

To summarize the epidemiological characteristics of severe fever with thrombocytopenia syndrome (SFTS) in Zhejiang Province, China.

METHODS

A standardized questionnaire was used to collect information on demographic features, exposure history, clinical symptoms, and timelines of medical visits. Descriptive statistics were used to analyze the characteristics of SFTS.

RESULTS

A total of 65 cases of SFTS were identified in Zhejiang Province from 2011 to 2013, of whom 34 were male and 31 were female. The median age was 66 years and 60 cases occurred in persons aged ≥ 50 years. The majority (91%) of SFTS cases occurred between May and August. With regard to exposure history, patients had pursued outdoor activities (63%), had a history of exposure to a tick (68%) or tick bite (29%), bred domestic animals (31%), or had a history of exposure to a mouse (57%), and some patients had a multi-exposure history. Approximately 98.46% of patients were hospitalized, and symptoms of the illness included fever (98%), fatigue (71%), chills (51%), etc. Two family clusters occurred, although there was no person-to-person transmission.

CONCLUSIONS

In Zhejiang Province, SFTS is prevalent between May and August among elderly persons who live in hilly areas, and clinical features are not specific. More emphasis should be given to this disease and further training of medical personnel should be carried out to prevent misdiagnosis.

Epidemiological characteristics of imported shigellosis in Korea, 2010-2011

Shigellosis is a global disease as food poisoning by infection of Shigella spp (S. dysenteriae, S. flexneri, S. boydii and S. sonnei). In Korea, approximately 500 cases of shigellosis have reported every year since 2004, and imported shigellosis is increasing gradually from 2006 in particular. According to increase of numbers of overseas travelers, the numbers of patients diseased with imported shigellosis is also increasing. We need continuous surveillance studies network (SSN) for control of imported shigellosis. We studied epidemiological characteristic of imported shigellosis by using database of Korea Centers for Disease Control and Prevention (KCDC) from 2010 to 2011. The imported shigellosis is analyzed on correlation with variable factors such as sex, age, symptom, visited country as well as Shigella spp in the database. Total 399 patients diseased with shigellosis have been reported between 2010 and 2011, The 212 patients (53.1%) among them were disease with imported shigellosis and the 205 patients (96.7%) were diagnosed as definite shigellosis. Shigella sonnei (65.6%) and Shigella flexneri (20.3%) were isolated in order. Clinical symptoms of the shigellosis were diarrhea (96.5%), abdominal pain (54.7%), fever (52.8%), chill (31.6%), and weakness (21.7% etc) in order. Duration of diarrhea was 1 to 5 days, the number of diarrhea was mostly more than 10 times, and type of stool was almost yellow stool. Almost shigellosis was occurred in the travelers visited to Asia (98.1%). Particularly, the occurrence rate of shigellosis was highest in traveler visited to Southeast Asia which is India (21.7%), Cambodia (19.8%), Philippines (17.9%), and Vietnam (9.0%) in order. According to increase of traveler to Southeast Asia, imported Shigellosis also increased. We need to strengthen the public health and hygiene, which is infection prevention rules, eating properly-cook food, washing hands, drinking boiled water, for traveler to Asia. The quarantine and surveillance system to control imported shigellosis is need continually in Korea.