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Scrub typhus, a miteborne rickettsiosis, has emerged in many areas globally. We analyzed the incidence and spatial-temporal distribution of scrub typhus in China during 1952-1989 and 2006-2016 using national disease surveillance data. A total of 133,623 cases and 174 deaths were recorded. The average annual incidence was 0.13 cases/100,000 population during 1952-1989; incidence increased sharply from 0.09/100,000 population in 2006 to 1.60/100,000 population in 2016. The disease, historically endemic to southern China, has expanded to all the provinces across both rural and urban areas. We identified 3 distinct seasonal patterns nationwide; infections peaked in summer in the southwest, summer-autumn in the southeast, and autumn in the middle-east. Persons >40 years of age and in nonfarming occupations had a higher risk for death. The changing epidemiology of scrub typhus in China warrants an enhanced disease control and prevention program.

Background: This study aimed to estimate influenza-like illness (ILI) prevalence, influenza-related healthcare seeking behaviors, and willingness for vaccination. Methods: A retrospective cross-sectional study based on a random dialing telephone survey was conducted from October 2017 through March 2018 to assess influenza-like illness prevalence and vaccination willingness among different demographic groups. Results: 10,045 individuals were enrolled and completed the survey. A total of 2834 individuals (28%) self-reported that they have suffered from influenza-like illness, especially children under 15 years of age. Overall willingness for influenza vaccination in the 2018/2019 influenza season was 45% and was positively associated with higher education level, recommendation from doctors, cost-free vaccination, and vaccination campaigns with employers&rsquo, support. Hospitalization and seeking medicine from pharmacies was less frequent in urban locations. People under 15 and over 60 years of age sought medical service more frequently. Conclusions: ILI prevalence differed significantly by age and geographical location/population density. Vaccination policy for motivating key populations at highest risk to vaccinate should take into consideration the awareness-raising of vaccination benefits, barriers reduction of vaccination such as cost, and recommendation via healthcare professionals.

Using fillers to toughen and reduce the brittleness of oil well cement (OWC) is very important for prolonging the service life of oil and gas wells. However, most studies have focused on investigating the reinforced mechanical properties of OWCs under static loads, which cannot be applied in predicting the service life of oil and gas wells because OWCs are usually exposed to dynamic loads in practice. In this study, the reinforced mechanical properties of OWCs under both dynamic and static loads are investigated for the first time, and microsphere rubber powders (MRPs) are adopted to reinforce G-class oil well cement. The results show that optimal mechanical properties and a maximum energy absorption rate exist under both dynamic and static loads, and the sample with MPR has the maximum impact resistance. In addition, blank cement is more prone to fracture under dynamic loading than under static loading. Under the dynamic load impact condition, the energy absorbed by the sample with MRP is much higher than that of blank cement, and the toughness of the sample increases. Based on the results of these tests and micromorphological observations, the energy dissipation mechanism of microsphere rubber powder for toughening and brittleness reduction is explained from three aspects: the long-range strain dispersion effects under loading, microcrack initiation and propagation effects, and peeling and tearing effects at the interface.

We compared the epidemiology of hepatitis A and hepatitis E cases in China from 1990-2014 to better inform policy and prevention efforts. The incidence of hepatitis A cases declined dramatically, while hepatitis E incidence increased. During 2004-2014, hepatitis E mortality rates surpassed those of hepatitis A.

Using national surveillance data for 120,111 human anthrax cases recorded during 1955-2014, we analyzed the temporal, seasonal, geographic, and demographic distribution of this disease in China. After 1978, incidence decreased until 2013, when it reached a low of 0.014 cases/100,000 population. The case-fatality rate, cumulatively 3.6% during the study period, has also decreased since 1990. Cases occurred throughout the year, peaking in August. Geographic distribution decreased overall from west to east, but the cumulative number of affected counties increased during 2005-2014. The disease has shifted from industrial to agricultural workers; 86.7% of cases occurred in farmers and herdsmen. Most (97.7%) reported cases were the cutaneous form. Although progress has been made in reducing incidence, this study highlights areas that need improvement. Adequate laboratory diagnosis is lacking; only 7.6% of cases received laboratory confirmation. Geographic expansion of the disease indicates that livestock control programs will be essential in eradicating anthrax.

Objective To determine morbidity and mortality from notifiable infectious diseases in China in 2015. Methods Descriptive analysis was used to analyze morbidity and mortality from notifiable diseases in China in 2015. Results In 2015, the morbidity rate for national notifiable diseases was 470.35 per 100,000 population, a decrease of 7.11% compared with the average for 2012–2014. The mortality rate was 1.23 per 100,000 population, a decrease of 1.27% compared with the average for 2012–2014. The percentage of laboratory diagnoses was 38.22%, an increase of 5.32% compared with 2012–2014. The five diseases with the highest reported incidences were hand, foot, and mouth disease, other infectious diarrhea, hepatitis B, tuberculosis, and syphilis. The diseases with the highest mortality reported were AIDS, tuberculosis, and rabies. Diseases transmitted by direct contact/fecal–oral transmission accounted for the largest proportion, 49.89%, of all reported cases, followed by blood-borne/sexually transmitted diseases, respiratory transmitted diseases, and zoonotic/vector-borne diseases. Pathogenic descriptive analysis showed that viral infectious diseases accounted for 68.48% of all cases, followed by bacterial infectious diseases and zoonotic/vector-borne diseases. Conclusion Epidemics of tuberculosis, dengue fever, brucellosis, AIDS, and rabies remain public health concerns in China. In addition, the proportion of laboratory-confirmed diagnoses of notifiable disease cases was low in 2015.

In recent years, the incidence of human brucellosis (HB) in the Shanxi province has ranked to be the top five among the 31 China provinces. HB data in Shanxi province between 2011 and 2016 were collected from the Centers for Disease Control and Prevention. Spatial and temporal distribution of HB was evaluated using spatial autocorrelation analysis and space-time scan analysis. The global Moran’s I index ranged from 0.37 to 0.50 between 2011 and 2016 (all P 0.05), and the “high-high” clusters of HB were located at the northern Shanxi, while the “low-low” clusters in the central and southeastern Shanxi. The high-incidence time interval was between March and July with a 2-fold higher risk of HB compared to the other months in the same year. One most likely cluster and three secondary clusters were identified. The radius of the most likely cluster region was 158.03 km containing 10,051 HB cases. Compared to the remaining regions, people dwelling in the most likely region were reported 4.50-fold ascended risk of incident HB. HB cases during the high-risk time interval of each year were more likely to be younger, to be males or to be farmers or herdsman than that during the low-risk time interval. The HB incidence had a significantly high correlation with the number of the cattle or sheep especially in the northern Shanxi. HB in Shanxi showed unique spatio-temporal clustering. Public health concern for HB in Shanxi should give priority to the northern region especially between the late spring and early summer.

To clarify the protective effect of one-dose mumps-containing vaccines (MuCV) in mainland China, the antigenic variations of HN gene and cross-neutralization capacities between MuCV and wild type genotype F MuVs were studied. In total, 70 HN gene sequences of genotype F MuV representative strains obtained from 2001 to 2015, two types of MuCV strains, 139 pairs of pre- and post-vaccination serum samples from infants receiving one dose of MuCV vaccination were analyzed. Genotype-specific amino acid variations were observed in the potential antigenic epitopes between MuCV and wild-type genotype F MuVs circulating in mainland China. The mumps neutralization antibody titers induced by one-dose MuCV were found to be generally low. Moreover, significant differences in neutralization titers were observed between vaccine and wild-type strains. It could be concluded that one-dose MuCV had a cross-protective effect against the wild-type genotype F MuVs, but its effectiveness was limited, which might be caused by insufficient doses of MuCV vaccination and the genotype-specific antigenic differences between vaccine and wild-type MuVs as well. In addition, a poor linear correlation between mumps-specific IgG concentrations and neutralization titers was observed in this study, indicating the concentration of MuV-specific IgG could not fully reflect the neutralizing antibody titer in serum. Therefore, it is highly recommended to provide a second dose of MuCV to preschool children to increase MuV neutralizing antibody titers and use MuV cross-neutralization test as preferred tool for assessment of mumps-containing vaccine effectiveness on wild-type MuVs. This is the first report to assess the effectiveness of one-dose Chinese MuCV against wild-type genotype F MuVs, which would be benefit for the development of mumps vaccination strategy.

Brucellosis, a zoonotic disease, was made statutorily notifiable in China in 1955. We analyzed the incidence and spatialtemporal distribution of human brucellosis during 1955-2014 in China using notifiable surveillance data: aggregated data for 1955-2003 and individual case data for 2004-2014. A total of 513,034 brucellosis cases were recorded, of which 99.3% were reported in northern China during 1955-2014, and 69.1% (258, 462/374, 141) occurred during February-July in 1990-2014. Incidence remained high during 1955-1978 (interquartile range 0.42-1.0 cases/100,000 residents), then decreased dramatically in 1979-1994. However, brucellosis has reemerged since 1995 (interquartile range 0.11-0.23 in 1995-2003 and 1.48-2.89 in 2004-2014); the historical high occurred in 2014, and the affected area expanded from northern pastureland provinces to the adjacent grassland and agricultural areas, then to southern coastal and southwestern areas. Control strategies in China should be adjusted to account for these changes by adopting a One Health approach., SCOPUS: ar.j, info:eu-repo/semantics/published

To learn the characteristics of morbidity and mortality of notifiable diseases reported in China in 2013.Descriptive analysis method was used to analyze the morbidity and mortality of notifiable diseases in China in 2013, with Microsoft Excel 2010 and ArcGIS 10.0 used to develop statistical charts.In 2013, the morbidity of the nationwide notifiable diseases was 473.87/100 000, a decrease of 3% below the average of the recent 3 years, while the mortality was 1.23/100 000, an increase of 2% over the average of the recent 3 years. The rate of laboratory diagnosis of the reported cases was 38.4%. Top 5 diseases of the reported incidence were hand foot and mouth disease, other infectious diarrhea, hepatitis B, tuberculosis and syphilis. The death cases reported were mainly AIDS, tuberculosis and rabies. As classified by the transmission route analysis, intestinal infectious diseases accounted for 49% of the total incidence reported for the year, followed by the blood and sexually transmitted infectious diseases, respiratory infectious diseases, animal and vector borne infectious diseases. According to the pathogenic analysis, virus infectious diseases accounted for 68% of the total cases, higher than bacterial infectious diseases and animal-borne/vector-borne infectious diseases. In Shanghai, Zhejiang and Jiangsu, human infection with avian influenza A (H7N9) virus was emerging, as epidemic situation of measles, dengue fever and brucellosis were on the rise significantly nationwide, while the morbidity of infectious diseases decreased, namely pulmonary tuberculosis, hepatitis B among others. Morbidity of the top 5 provinces for notifiable infectious diseases were Hainan, Guangxi, Guangdong, Xinjiang and Zhejiang, respectively.The proportion of laboratory confirmed cases among totals was still low in 2013. The morbidity of the infectious diseases was higher in western provinces and parts of south-eastern province, the mortality was higher in western provinces. The emerging human infection with avian influenza A (H7N9) virus, and the high epidemic of measles, dengue fever and brucellosis in some areas had caught the society concerns.

BACKGROUND The novel influenza A(H7N9) virus has caused 2013 spring and 2013-2014 winter waves of human infections since its first emergence in China in March 2013. Exposure to live poultry is a risk factor for H7N9 infection. Public psychobehavioral responses often change during progression of an epidemic. METHODS We conducted population-based surveys in southern China to examine human exposure to live poultry, and population psychological response and behavioral changes in the two waves. In Guangzhou, an urban area of Guangdong province, we collected data using telephone surveys with random digit dialing in May-June 2013 and again in December 2013 to January 2014. In Zijin county, a rural area of the same province, we used door-to-door surveys under a stratified sampling design in July 2013 and again in December 2013 to January 2014. All responses were weighted by age and sex to the respective adult populations. FINDINGS Around half of the urban respondents (53.8%) reported having visited LPMs in the previous year in the first survey, around double that reported in the second survey (27.7%). In the rural surveys, around half of the participants reported raising backyard poultry in the past year in the first survey, increasing to 83.2% participants in the second survey. One third of urban subjects supported the permanent closure of LPMs in the first and second surveys, and factors associated with support for closure included female sex, higher level of worry towards H7N9, and worry induced by a hypothetical influenza-like illness. CONCLUSIONS Our study indicated high human exposure to live poultry and low support for permanent closure of markets in both urban and rural residents regardless of increased worry during the epidemic.

Exposure was common in urban and rural areas and remains a potential risk factor for human infection., 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.

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.We collected the amount of MPM signals, response results of signals in CIDARS, cases data in nationwide Notifiable Infectious Diseases Reporting Information System, and outbreaks data in Public Health Emergency Reporting System of 16 infectious diseases in 31 provinces in Chinese mainland from January 2011 to October 2013. The threshold with the optimal sensitivity, the shortest time to detect outbreak and the least number of signals was considered as the best threshold of each disease in Chinese mainland and in each province.Among all the 16 diseases, the optimal thresholds of 10 diseases, including dysentery, dengue, hepatitis A, typhoid and paratyphoid, meningococcal meningitis, Japanese encephalitis, scarlet fever, leptospirosis, hepatitis, typhus in country level were the 90(th) percentile (P90), which was the same as provincial level for those diseases.For the other 6 diseases, including other infectious diarrhea, influenza, acute hemorrhagic conjunctivitis, mumps, rubella and epidemic hemorrhagic fever, the nationwide optimal thresholds were the 80th percentile (P80), which was different from that by provinces for each disease. For these 6 diseases, the number of signals generated by MPM with the optimal threshold for each province was decreased by 23.71% (45 557), 15.59% (6 124), 14.07% (1 870), 9.44% (13 881), 8.65% (1 294) and 6.03% (313) respectively, comparing to the national optimal threshold, while the sensitivity and time to detection of CIDARS were still the same.Optimizing the threshold by different diseases and provinces for MPM in CIDARS could reduce the number of signals while maintaining the same sensitivity and time to detection.

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.The amount of signals, response situation and verification outcome of signals related to 32 infectious diseases of 31 provinces in mainland China in CIDARS were investigated from 2011 to 2013, the changes by year on the proportion of responded signals and timeliness of signal response were descriptively analyzed.A total of 960 831 signals were generated nationwide on 32 kinds of infectious diseases in the system, with 98.87% signals (949 936) being responded, and the median (the 25(th) percentile to the 75(th) percentile (P25-P75) ) of time to response was 1.0 (0.4-3.3) h. Among all the signals, 242 355 signals were generated by the fixed-value detection method, the proportion of responded signals was 96.37% (62 349/64 703), 98.75% (68 413/69 282) and 99.37% (107 690/108 370), respectively, and the median (P25-P75) of time to response was 1.3 (0.3-9.7), 0.8(0.2-4.9) and 0.7 (0.2-4.2) h, respectively. After the preliminary data verification, field investigation and laboratory test by local public health staffs, 100 232 cases (41.36%) were finally confirmed.In addition, 718 476 signals were generated by the temporal aberration detection methods, and the average amount of signal per county per week throughout the country were 1.53, and 8 155 signals (1.14%) were verified as suspected outbreaks. During these 3 years, the proportion of signal response was 98.89% (231 149/233 746), 98.90% (254 182/257 015) and 99.31% (226 153/227 715), respectively, and the median (P25-P75) of time to response was 1.1 (0.5-3.3), 1.0 (0.5-2.9) and 1.0 (0.5-2.6) h, respectively.From 2011 to 2013, the proportion of responded signals and response timeliness of CIDARS maintained a rather high level, and further presented an increasing trend year by year. But the proportion of signals related to suspected outbreaks should be improved.

An item parameter estimation procedure is cedure was pro-developed using an EM algorithm for Samejima's (1973) continuous item response model. The potential usefulness of this model is examined, including the density function and the practical meaning of the item parameters and statistical properties of the model. The expected a posteriori and maximum likelihood estimates of the person (0) parameters and their associated standard errors are also described. The item parameter estimation pro grammed and evaluated using simulated data. The results show that the estimation procedure performs well in estimating item and 0 parameters. These estimation procedures should permit the application of the continuous response model to many measurement problems.

Item parameter estimation for the threeparameter logistic model (3PLM) is sometimes problematic. The estimation algorithm of the 3PLM maximum likelihood estimation procedure often fails, which results in invalid parameter estimates. A procedure based on the marginal Bayesian estimation method introduced by Bock & Aitkin (1981), Swaminathan & Gifford (1985, 1986), and Mislevy & Bock (1990) is proposed here to improve the item parameter estimates for the 3PLM. Four-parameter beta distributions are used as prior distributions for estimating item parameters. A computer simulation study suggested that implementing the marginal Bayesian estimation algorithm with four-parameter beta prior distributions and then updating the priors with empirical means of the updated intermediate estimates can improve item parameter estimation when accurate prior information about the unknown parameters is not available.

An IRT method for estimating conditional standard errors of measurement of scale scores is presented, where scale scores are nonlinear transformations of number-correct scores. The standard errors account for measurement error that is introduced due to rounding scale scores to integers. Procedures for estimating the average conditional standard error of measurement for scale scores and reliability of scale scores are also described. An illustration of the use of the methodology is presented, and the results from the IRT method are compared to the results from a previously developed method that is based on strong true-score theory.

Large-sample standard errors of linear equating for the counterbalanced design are derived using the general delta method. Computer simulations were conducted to compare the standard errors derived by Lord under the normality assumption with those derived in this article without such an assumption. The standard errors derived without the normality assumption were found to be more accurate than those derived with the normality assumption in an example using large sample size and moderately skewed score distributions. In an example using nearly symmetric distributions, the standard errors computed with the normality assumption were found to be at least as accurate as those derived without the normality assumption.

An alternative approach for item response theory observed-score equating is described. The number- correct score distributions needed in equating are found by numerical integration over the theoretical or empiri cal distributions of examinees' traits. The item response theory true-score equating method and the observed- score equating method described by Lord, in which the number-correct score distributions are summed over a sample of trait estimates, are compared in a real test example. In a computer simulation, the observed-score equating methods based on numerical integration and summation were compared using data generated from standard normal and skewed populations. The method based on numerical integration was found to be less biased, especially at the two ends of the score distribu tion. This method can be implemented without the need to estimate trait level for individual examinees, and it is less computationally intensive than the method based on summation.

A general delta method is described for computing the standard error (SE) of a chain of linear equatings. The general delta method derives the SEs directly from the moments of the score distributions obtained in the equating chain. The partial derivatives of the chain equating function needed for computing the SEs are de rived numerically. The method can be applied to equatings using the common-items nonequivalent populations design. Computer simulations were con ducted to evaluate the SEs of a chain of two equatings using the Levine and Tucker methods. The general delta method was more accurate than a method that as sumes the equating processes in the chain are statisti cally independent. Index terms: chain equating, delta method, equating, linear equating, standard error of equating.

The delta method was used to derive standard errors (SEs) of the Levine observed score and Levine true score linear equating methods. SEs with a normality assumption as well as without a nor mality assumption were derived. Data from two forms of a test were used as an example to evalu ate the derived SEs of equating. Bootstrap SEs also were computed for the purpose of comparison. The SEs derived without the normality assumption and the bootstrap SEs were very close. For the skewed score distributions, the SEs derived with the normality assumption differed from the SEs derived without the normality assumption and the boot strap SEs.

A numerical approach for computing standard errors (SES) of a linear equating is described. In the proposed approach, the first partial derivatives of the equating function needed to compute the SES are derived numerically. Thus, the difficulty of deriving the analytical formulas of the partial derivatives for a complicated equating method is avoided. The numerical and analytical approaches were compared using the Tucker equating method. The SES derived numerically were found to be indistinguishable from the SES derived analytically. In a computer simulation of the numerical approach using the Levine equating method, the SES based on the normality assumption were found to be less accurate than those derived without the normality assumption when the score distributions were skewed.