[Show abstract][Hide abstract] ABSTRACT: A public health emergency of international concern regarding the 2014 West African Ebola epidemic was declared by the WorldHealth Organization on August 8, 2014, in view of its potential for further international spread. Based on historic traveller flightitinerary data between October and December 2013 from the International Air Transport Association, we assessed the potential risk ofEbola virus exportation from three West African Countries, Guinea, Liberia, and Sierra Leone, into China via commercial air travelbetween October 1, 2014 and December 31, 2014. We found 107,113 passengers departed from the three affected countries during thefourth quarter of 2013, with 3167 people (3.0%) arriving in mainland China after transfers at the international airports of eightcountries, including France, Belgium, and the U.A.E. The primary airports of entry into China for travelers from Guinea, Liberia, andSierra Leone are located in Beijing, Guangzhou, Shanghai, Hangzhou, Wuhan, Chongqing, and Dalian, whereas the main finaldestinations in China include Beijing, Guangzhou, Chongqing, Wuhan, Shanghai, Hangzhou, and Wenzhou. With the assumption thattravel behavior and mobility in the fourth quarter of 2014 will be the same as that of 2013, an average of 2235 international travellerswould need to be screened at the points of entry into China to capture one traveler with potential exposure to Ebola virus in the threeWest African countries. In total, our model projects only 0.54 travellers infected with Ebola virus departing the above three countriesentering China via commercial flights from October to December 2014 (0.35 infected travellers from Liberia, 0.16 from Sierra Leone,and 0.03 from Guinea). If the incidence of Ebola virus disease increases or the number of travellers to China decreases, the number oftravellers with Ebola virus infection would fluctuate accordingly. This study shows that the risk of Ebola imported from West Africa toChina via commercial air travel exists, although it is very low. China could support screening of departing international travellers fromWest Africa for the early detection of individuals with Ebola virus disease, screen high-risk traveller populations at the primary pointsof entry into China, and heighten surveillance in China's leading destination cities.
Chinese Science Bulletin (Chin Ver). 12/2014; 59(36).
[Show abstract][Hide abstract] ABSTRACT: Background
In China, the national malaria elimination programme has been operating since 2010. This study aimed to explore the epidemiological changes in patterns of malaria in China from intensified control to elimination stages.
Data on nationwide malaria cases from 2004 to 2012 were extracted from the Chinese national malaria surveillance system. The secular trend, gender and age features, seasonality, and spatial distribution by Plasmodium species were analysed.
In total, 238,443 malaria cases were reported, and the proportion of Plasmodium falciparum increased drastically from <10% before 2010 to 55.2% in 2012. From 2004 to 2006, malaria showed a significantly increasing trend and with the highest incidence peak in 2006 (4.6/100,000), while from 2007 onwards, malaria decreased sharply to only 0.18/100,000 in 2012. Males and young age groups became the predominantly affected population. The areas affected by Plasmodium vivax malaria shrunk, while areas affected by P. falciparum malaria expanded from 294 counties in 2004 to 600 counties in 2012.
This study demonstrated that malaria has decreased dramatically in the last five years, especially since the Chinese government launched a malaria elimination programme in 2010, and areas with reported falciparum malaria cases have expanded over recent years. These findings suggest that elimination efforts should be improved to meet these changes, so as to achieve the nationwide malaria elimination goal in China in 2020.
[Show abstract][Hide abstract] ABSTRACT: Closure of live poultry markets was implemented in areas affected by the influenza virus A(H7N9) outbreak in China during winter, 2013-14. Our analysis showed that closing live poultry markets in the most affected cities of Guangdong and Zhejiang provinces was highly effective in reducing the risk for H7N9 infection in humans.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the performance of China's infectious disease automated alert and response system in the detection of outbreaks of hand, foot and mouth (HFM) disease.
Bulletin of the World Health Organisation 09/2014; 92(9):656-63. · 5.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate human exposure to live poultry and changes in risk perception and behavior after the April 2013 influenza A(H7N9) outbreak in China, we surveyed 2,504 urban residents in 5 cities and 1,227 rural residents in 4 provinces and found that perceived risk for influenza A(H7N9) was low. The highest rate of exposure to live poultry was reported in Guangzhou, where 47% of those surveyed reported visiting a live poultry market >1 times in the previous year. Most (77%) urban respondents reported that they visited live markets less often after influenza A(H7N9) cases were first identified in China in March 2013, but only 30% supported permanent closure of the markets to control the epidemic. In rural areas, 48% of respondents reported that they raised backyard poultry. Exposure to live commercial and private poultry is common in urban and rural China and remains a potential risk factor for human infection with novel influenza viruses.
[Show abstract][Hide abstract] ABSTRACT: Clostridium difficile is a well-known nosocomial infectious pathogen. Research on C. difficile infection has primarily focused on strains, such as the hypervirulent PCR ribotype 027 (ST1) emerging in Europe and North America. However, other new emerging ribotypes have become arrestive in some countries, such as PCR ribotype 17 (ST37) in Asia and Latin America. Here we collected seventy strains, and their toxin genes, tcdA and tcdB, were sequenced; multi-locus sequence typing was used to study their population structure. In addition, tcdA and/or tcdB sequences of 25 further isolates were obtained from GenBank. Single nucleotide polymorphisms were identified and analyzed. Phylogenetics were performed to study toxin gene evolution. All tcdA and tcdB sequences could be divided into 16 types denoted A01-16 and B01-16, respectively. Hypervirulent strain RT027 is A13B12 and RT078 is A14B10, whereas the newly epidemic strain RT017 is A15B13. SNP analysis suggests the possibility of recombination in tcdB, perhaps through horizontal gene transfer. SNPs were also found in the sequences corresponding to the PCR primers widely used for toxin detection. Our study shows, the ST037 shares few genotypic features in its tcdA and tcdB genes with some known hypervirulent strains, for their falling into a unique clade. And our findings can be used to more finely map the relationships among C. difficile strains, than less sensitive methods such as toxinotyping or even MLST, to reveal their inherent epidemiology characteristics.
[Show abstract][Hide abstract] ABSTRACT: To analyze the viral etiologies of hospitalized pneumonia patients aged less than five years in six provinces during 2009-2012, and to describe the seasonality of the detected viral etiologies.
[Show abstract][Hide abstract] ABSTRACT: To analyze the implement performance of China Infectious Diseases Automated-alert and Response System (CIDARS) of 31 provinces in mainland China, and to provide the evidences for further promoting the application and improvement of this system.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 04/2014; 48(4):252-8.
[Show abstract][Hide abstract] ABSTRACT: Providing evidences for further modification of China Infectious Diseases Automated-alert and Response System (CIDARS) via analyzing the outbreak detection performance of Moving Percentile Method (MPM) by optimizing thresholds in different provinces.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 04/2014; 48(4):265-9.
[Show abstract][Hide abstract] ABSTRACT: Objective For better application of spatial scan statistic method in early warning of infectious disease outbreak,we need to choose different parameters for spatial scan statistic method. Methods We took the cases and outbreaks of hand-foot-and-mouth disease( HFMD) and dysentery reported by Shandong and Hunan provinces in 2009 as data source. Taking sensitivity and positive prediction ratio as evaluation indices,w e compared the performance of thirty groups of parameters on these tw o diseases. Results For the dysentery cases in Hunan province,taking the sum of cases in four days w ith 1-rank coefficients,w e could get the best performance. For the hand-foot-and-mouth disease( HFMD) cases in Shandong province,taking the sum of cases in three days directly,w e could get the best performance. Conclusion When applying spatial scan statistic method in early w arning of infectious disease outbreak,w e ought to choose different parameters for different kinds of infectious disease in order to get the best results. In next steps,w e out to choose the best parameters based on the different incidence rates.
Chinese Journal of Health Statistics. 04/2014; 31(2):236-239.
[Show abstract][Hide abstract] ABSTRACT: For providing evidences for further modification of China Infectious Diseases Automated-alert and Response System (CIDARS) by comparing the early-warning performance of the temporal model and temporal-spatial model in CIDARS.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 04/2014; 48(4):259-64.
[Show abstract][Hide abstract] ABSTRACT: Acute lower respiratory infections (ALRIs) are an important cause of acute illnesses and mortality worldwide and in China. However, a large-scale study on the prevalence of viral infections across multiple provinces and seasons has not been previously reported from China. Here, we aimed to identify the viral etiologies associated with ALRIs from 22 Chinese provinces.
PLoS ONE 01/2014; 9(6):e99419. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An outbreak detection and response system, using time series moving percentile method based on historical data, in China has been used for identifying dengue fever outbreaks since 2008. For dengue fever outbreaks reported from 2009 to 2012, this system achieved a sensitivity of 100%, a specificity of 99.8% and a median time to detection of 3 days, which indicated that the system was a useful decision tool for dengue fever control and risk-management programs in China.
PLoS ONE 01/2014; 9(8):e106144. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The novel influenza A H7N9 virus emerged recently in mainland China, whereas the influenza A H5N1 virus has infected people in China since 2003. Both infections are thought to be mainly zoonotic. We aimed to compare the epidemiological characteristics of the complete series of laboratory-confirmed cases of both viruses in mainland China so far.
An integrated database was constructed with information about demographic, epidemiological, and clinical variables of laboratory-confirmed cases of H7N9 (130 patients) and H5N1 (43 patients) that were reported to the Chinese Centre for Disease Control and Prevention until May 24, 2013. We described disease occurrence by age, sex, and geography, and estimated key epidemiological variables. We used survival analysis techniques to estimate the following distributions: infection to onset, onset to admission, onset to laboratory confirmation, admission to death, and admission to discharge.
The median age of the 130 individuals with confirmed infection with H7N9 was 62 years and of the 43 with H5N1 was 26 years. In urban areas, 74% of cases of both viruses were in men, whereas in rural areas the proportions of the viruses in men were 62% for H7N9 and 33% for H5N1. 75% of patients infected with H7N9 and 71% of those with H5N1 reported recent exposure to poultry. The mean incubation period of H7N9 was 3·1 days and of H5N1 was 3·3 days. On average, 21 contacts were traced for each case of H7N9 in urban areas and 18 in rural areas, compared with 90 and 63 for H5N1. The fatality risk on admission to hospital was 36% (95% CI 26-45) for H7N9 and 70% (56-83%) for H5N1.
The sex ratios in urban compared with rural cases are consistent with exposure to poultry driving the risk of infection-a higher risk in men was only recorded in urban areas but not in rural areas, and the increased risk for men was of a similar magnitude for H7N9 and H5N1. However, the difference in susceptibility to serious illness with the two different viruses remains unexplained, since most cases of H7N9 were in older adults whereas most cases of H5N1 were in younger people. A limitation of our study is that we compared laboratory-confirmed cases of H7N9 and H5N1 infection, and some infections might not have been ascertained.
Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease and University Grants Committee, Hong Kong Special Administrative Region, China; and the US National Institutes of Health.
[Show abstract][Hide abstract] ABSTRACT: Characterisation of the severity profile of human infections with influenza viruses of animal origin is a part of pandemic risk assessment, and an important part of the assessment of disease epidemiology. Our objective was to assess the clinical severity of human infections with avian influenza A H7N9 virus, which emerged in China in early 2013.
We obtained information about laboratory-confirmed cases of avian influenza A H7N9 virus infection reported as of May 28, 2013, from an integrated database built by the Chinese Center for Disease Control and Prevention. We estimated the risk of fatality, mechanical ventilation, and admission to the intensive care unit for patients who required hospital admission for medical reasons. We also used information about laboratory-confirmed cases detected through sentinel influenza-like illness surveillance to estimate the symptomatic case fatality risk.
Of 123 patients with laboratory-confirmed avian influenza A H7N9 virus infection who were admitted to hospital, 37 (30%) had died and 69 (56%) had recovered by May 28, 2013. After we accounted for incomplete data for 17 patients who were still in hospital, we estimated the fatality risk for all ages to be 36% (95% CI 26-45) on admission to hospital. Risks of mechanical ventilation or fatality (69%, 95% CI 60-77) and of admission to an intensive care unit, mechanical ventilation, or fatality (83%, 76-90) were high. With assumptions about coverage of the sentinel surveillance network and health-care-seeking behaviour for patients with influenza-like illness associated with influenza A H7N9 virus infection, and pro-rata extrapolation, we estimated that the symptomatic case fatality risk could be between 160 (63-460) and 2800 (1000-9400) per 100 000 symptomatic cases.
Human infections with avian influenza A H7N9 virus seem to be less serious than has been previously reported. Many mild cases might already have occurred. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection.
Chinese Ministry of Science and Technology; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; US National Institute of Allergy and Infectious Disease; and the US National Institutes of Health.
[Show abstract][Hide abstract] ABSTRACT: We investigated a cluster of five cases of severe pneumonia from one village in Yunnan Province, China. We searched for severe pneumonia in the village and hospitals. We interviewed patients and family members about exposures. We tested acute and convalescent sera for antigen and antibody of severe acute respiratory syndrome, avian influenza, and plague. The only common exposure of the five patients was riding together in the enclosed cab of a truck for 1.5 hours while taking the first patient to the hospital. Seroconversion to plague F1 antigen confirmed plague in three survivors. Unfamiliarity of clinicians with plague and lack of sputum examination, blood culture, or postmortem examination delayed the diagnosis. No plague cases occurred among family and village contacts and health care workers. High infectivity in this cluster was limited to a crowded, poorly ventilated truck.
The American journal of tropical medicine and hygiene 03/2013; · 2.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND:: Acute diarrhea is a leading cause of childhood morbidity and mortality worldwide, but there have been few reports on the causative viruses associated with acute diarrhea among outpatient children in developing countries. This study was conducted to identify the viral agents in outpatient children with acute diarrhea in southeastern China. METHODS:: 811 outpatient children 5 years of age or younger with acute diarrhea were enrolled. Five enteric viruses were determined by ELISA and Multiplex RT-PCR for each stool specimen. RESULTS:: At least one virus was detected in 353 (43.5%) of the subjects. The proportions of rotavirus, norovirus, sapovirus, adenovirus and astrovirus were 25.5%, 18.1%, 4.4%, 2.7% and 1.2%, respectively. G3P was the most prevalent rotavirus strain. Mixed infections were observed in 65 cases, among which the most prevalent co-infection was rotavirus with other viruses (58 cases, 89.2%). Rotavirus and norovirus infections showed marked and opposing seasonal patterns. Mixed infection was significantly more common in children greater than 1 year old (12.2%) than in those less than 1 year old (7.1%) (P=0.026). Clinically, rotavirus infection presented with a longer duration (4.3± 6.7 days) and higher frequency (5.9± 2.0 times/day) of diarrhea than any other viral infection. Vomiting was more common for mixed infections than for single infections (P=0.010). CONCLUSIONS:: All the five common etiologies were detected in this study, with rotavirus and norovirus being the two leading agents. Mixed viral infections were common in outpatient children with acute diarrhea, and rotavirus seemed to play a major role in mixed infections.
The Pediatric Infectious Disease Journal 02/2013; · 3.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We evaluated a novel strategy to improve the performance of outbreak detection algorithms, namely setting the alerting threshold separately in each region according to the disease incidence in that region. By using data on hand, foot and mouth disease in Shandong province, China, we evaluated the impact of disease incidence on the performance of outbreak detection algorithms (EARS-C1, C2 and C3). Compared to applying the same algorithm and threshold to the whole region, setting the optimal threshold in each region according to the level of disease incidence (i.e., high, middle, and low) enhanced sensitivity (C1: from 94.4% to 99.1%, C2: from 93.5% to 95.4%, C3: from 91.7% to 95.4%) and reduced the number of alert signals (the percentage of reduction is C1∶4.3%, C2∶11.9%, C3∶10.3%). Our findings illustrate a general method for improving the accuracy of detection algorithms that is potentially applicable broadly to other diseases and regions.
PLoS ONE 01/2013; 8(8):e71803. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dengue fever has been a major public health concern in China since it re-emerged in Guangdong province in 1978. This study aimed to explore spatiotemporal characteristics of dengue fever cases for both indigenous and imported cases during recent years in Guangdong province, so as to identify high-risk areas of the province and thereby help plan resource allocation for dengue interventions.
Notifiable cases of dengue fever were collected from all 123 counties of Guangdong province from 2005 to 2010. Descriptive temporal and spatial analysis were conducted, including plotting of seasonal distribution of cases, and creating choropleth maps of cumulative incidence by county. The space-time scan statistic was used to determine space-time clusters of dengue fever cases at the county level, and a geographical information system was used to visualize the location of the clusters. Analysis were stratified by imported and indigenous origin.
1658 dengue fever cases were recorded in Guangdong province during the study period, including 94 imported cases and 1564 indigenous cases. Both imported and indigenous cases occurred more frequently in autumn. The areas affected by the indigenous and imported cases presented a geographically expanding trend over the study period. The results showed that the most likely cluster of imported cases (relative risk = 7.52, p < 0.001) and indigenous cases (relative risk = 153.56, p < 0.001) occurred in the Pearl River Delta Area; while a secondary cluster of indigenous cases occurred in one district of the Chao Shan Area (relative risk = 471.25, p < 0.001).
This study demonstrated that the geographic range of imported and indigenous dengue fever cases has expanded over recent years, and cases were significantly clustered in two heavily urbanised areas of Guangdong province. This provides the foundation for further investigation of risk factors and interventions in these high-risk areas.