The impact of preoperative biliary drainage on postoperative healthcare-associated infections and clinical outcomes following pancreaticoduodenectomy: a ten-year retrospective analysis.

BACKGROUND: Pancreaticoduodenectomy (PD) is a complex procedure and easily accompanied by healthcare-associated infections (HAIs). This study aimed to assess the impact of PBD on postoperative infections and clinical outcomes in PD patients. METHODS: The retrospective cohort study were conducted in a tertiary hospital from January 2013 to December 2022. Clinical and epidemiological data were collected from HAIs surveillance system and analyzed. RESULTS: Among 2842 patients who underwent PD, 247 (8.7%) were diagnosed with HAIs, with surgical site infection being the most frequent type (n = 177, 71.7%). A total of 369 pathogenic strains were detected, with Klebsiella pneumoniae having the highest proportion, followed by Enterococcu and Escherichia coli. Although no significant association were observed generally between PBD and postoperative HAIs, subgroup analysis revealed that PBD was associated with postoperative HAIs in patients undergoing robotic PD (aRR = 2.174; 95% CI:1.011-4.674; P = 0.047). Prolonging the interval between PBD and PD could reduce postoperative HAIs in patients with cholangiocarcinoma (≥4 week: aRR = 0.292, 95% CI 0.100-0.853; P = 0.024) and robotic PD (≤2 week: aRR = 3.058, 95% CI 1.178-7.940; P = 0.022). PBD was also found to increase transfer of patients to ICU (aRR = 1.351; 95% CI 1.119-1.632; P = 0.002), extended length of stay (P < 0.001) and postoperative length of stay (P = 0.004). CONCLUSION: PBD does not exhibit a significant association with postoperative HAIs or other outcomes. However, the implementation of robotic PD, along with a suitable extension of the interval between PBD and PD, appear to confer advantages concerning patients' physiological recuperation. These observations suggest potential strategies that may contribute to enhanced patient outcomes.

Epidemiology and risk factors of nosocomial infections in a Chinese tertiary-care hospital: a 10-year retrospective case-control study.

BACKGROUND: Nosocomial infections (NIs) are the most frequent adverse events among patients and cause a heavy burden on both health and economics. To investigate epidemiology of NIs and identify risk factors for NIs by integrating continuous long-term surveillance data. METHODS: We performed an observational study among inpatients at the Chinese People's Liberation Army General Hospital between January 1, 2010, and December 31, 2019. Infection rates, mortality rates and percentage of NIs were calculated. Trends of yearly infection rates by pathogens were assessed using Mann-Kendall trend test. Controls were matched to cases (2:1) by age (±2 years), sex, admission date (±1 year) and admission diagnosis, and conditional logistic regression was used to estimate odds ratios. RESULTS: A total of 1,534,713 inpatients were included among which 33,468 NIs cases occurred with an infection rate of 2.18%. The most common infections were respiratory system infection (52.22%), bloodstream infection (17.60%), and genitourinary system infection (15.62%). Acinetobacter. baumannii (9.6%), Klebsiella. pneumoniae (9.0%), Pseudomonas. aeruginosa (8.6%), Escherichia. coli (8.6%) and Enterococcus. faecium (5.0%) were the top five isolated pathogens. Infection rates of K. pneumoniae and carbapenems-resistant K. pneumoniae significantly increased. Prior ICU stay, surgery, any device placement (including central venous catheter, mechanical ventilation, urinary catheter, and tracheotomy), prior use of triple or more antibiotics combinations, carbapenem, and ß-Lactamase inhibitors were significantly associated with NIs. CONCLUSION: K. pneumoniae has the potential to cause a clinical crisis with increasing infection rates and carbapenem resistance. Clinical management of invasive operations and antibiotics use should be further strengthened.

Epidemiology of healthcare-associated infections and outcomes among open and robotic pancreatoduodenectomy: A retrospective study from 2013 to 2022.

BACKGROUND AND AIM: Healthcare-associated infections (HAIs) after pancreaticoduodenectomy (PD) are one of the common postoperative complications. This study aims to investigate the epidemiology of postoperative HAIs in patients with open pancreaticoduodenectomy (OPD) and robotic pancreaticoduodenectomy (RPD). METHODS: This retrospective cohort study described the trend of HAIs in patients undergoing PD from January 2013 to December 2022 at a tertiary hospital. Patients were divided into OPD and RPD, and the HAIs and outcomes were compared. RESULTS: Among 2632 patients who underwent PD, 230 (8.7%, 95% confidence interval [CI] 7.7-9.9%) were diagnosed with HAIs, with a decreasing trend from 2013 to 2022 (P < 0.001 for trend). The incidence of postoperative HAIs was significantly higher in patients with OPD than RPD (9.6% vs 5.8%; P = 0.003). The incidence of HAIs for patients with OPD showed a decreasing trend (P = 0.001 for trend), and the trend for RPD was not significant (P = 0.554 for trend). Logistic regression showed that RPD was significantly associated with postoperative HAIs after adjusting for covariates (adjusted odds ratio = 0.654; 95% CI 0.443-0.965; P = 0.032), especially in the subgroup of patients without preoperative biliary drainage (adjusted odds ratio = 0.486; 95% CI 0.292-0.809; P = 0.006). Regarding clinical outcomes, RPD has a shorter length of stay and a more expensive charge than OPD (all P < 0.05). CONCLUSION: Postoperative HAIs in patients with PD showed a decreasing trend in recent years, especially in OPD. RPD was significantly associated with reduced postoperative HAIs and length of stay, although the charge is more expensive. Attention should be paid to postoperative HAIs in OPD, and it is imperative to continue reducing the costs of RPD.

Development of Woolly Hair and Hairlessness in a CRISPR-Engineered Mutant Mouse Model with KRT71 Mutations.

Hypotrichosis simplex (HS) and woolly hair (WH) are rare and monogenic disorders of hair loss. HS, characterized by a diffuse loss of hair, usually begins in early childhood and progresses into adulthood. WH displays strong coiled hair involving a localized area of the scalp or covering the entire side. Mutations in the keratin K71(KRT71) gene have been reported to underlie HS and WH. Here, we report the generation of a mouse model of HS and WH by the co-injection of Cas9 mRNA and sgRNA, targeting exon6 into mouse zygotes. The Krt71-knockout (KO) mice displayed the typical phenotypes, including Krt71 protein expression deletion and curly hair in their full body. Moreover, we found that mice in 3-5 weeks showed a new phenomenon of the complete shedding of hair, which was similar to nude mice. However, we discovered that the mice exhibited no immune deficiency, which was a typical feature of nude mice. To our knowledge, this novel mouse model generated by the CRISPR/Cas9 system mimicked woolly hair and could be valuable for hair disorder studies.

Retrospective Analysis of Epidemiology, Risk Factors, and Outcomes of Health Care-Acquired Carbapenem-Resistant Klebsiella pneumoniae Bacteremia in a Chinese Tertiary Hospital, 2010-2019.

INTRODUCTION: In the present study, we aimed to describe the proportion of carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) in KP-BSI in one Chinese tertiary hospital over 10 years and determine the risk factors and outcomes of CRKP-BSI. METHODS: We retrospectively analyzed clinical and microbiological data of patients with KP-BSI from January 2010 to December 2019 to identify risk factors, clinical features, and outcomes using multivariate logistic regression analysis. KP-BSI only included monomicrobial BSI and health care-acquired BSI. RESULTS: Among the total 687 isolates of KP-BSI in this study, the rate of CRKP was 39.0% (268/687); this rate in the intensive care unit (ICU) was 65.6% and that in seven high-risk departments (including four ICUs, respiratory medicine, gastroenterology medicine, and hepatobiliary surgery) was 74.6%. The annual rate of CRKP in KP-BSI ranged from 0.0% in 2010 to 54.5% in 2019. The 28-day mortality was 36.2% in patients with CRKP-BSI and 11.7% in those with carbapenem-susceptible K. pneumoniae (CSKP) BSI. Multivariable logistic regression analysis showed that prior ICU stay (odds ratio [OR] 2.485, P < 0.001), hospital stay ≥ 30 days prior to BSI (OR 1.815, P = 0.007), prior mechanical ventilation (OR 2.020, P = 0.014), prior urinary catheter (OR 1.999, P = 0.003), prior carbapenem use (OR 3.840, P < 0.001), hepatobiliary disease (OR 2.943, P < 0.001), pancreatitis (OR 2.700, P = 0.026), and respiratory disease (OR 2.493, P = 0.009) were risk factors of CRKP-BSI. Patients with a first admission (OR 0.662, P = 0.046) had a lower percentage of CRKP-BSI. CONCLUSION: The rapidly rising rate of CRKP-BSI in KP with high mortality requires increased attention. Exposure to carbapenems, ICU stay, invasive mechanical ventilation or urinary catheter, prolonged hospital stay, hepatobiliary disease, pancreatitis, and respiratory disease were found to be risk factors for CRKP-BSI. Strict control measures should be implemented to prevent the emergence and spread of CRKP, especially in high-risk departments.

Epidemiological Characteristics and Drug Resistance of Fungemia in General Hospitals from 2010 to 2019.

OBJECTIVE: This study intends to analyze the data of fungemia in a large tertiary hospital from 2010 to 2019, and is aimed at understanding its epidemic characteristics and drug resistance. METHODS: The "Hospital Infection Real-Time Monitoring System" was used to retrieve the case information of patients who were hospitalized for more than 48 hours from 2010 to 2019. The questionnaire was designed to collect patients' basic information, infection situation, drug resistance, and other related information. Statistical software was used for analysis. RESULTS: The fungi detection rate was in the range of 0.19%~0.75% in ten years, the average rate was 0.29%, and the rate 0.2%~0.3% since 2013, which was lower than that from 2010 to 2012. Non-Candida albicans was the main fungus, accounting for 62.50%. The drug resistance of non-C. albicans was higher than that of C. albicans, among which C. glabrata had the highest resistance rate. Data analysis showed that the patients with more serious basic diseases, combined with infection of other sites, surgery, long hospital stay, combination of antibiotics, and invasive catheterization, were more likely to occur fungemia. CONCLUSION: We should pay more attention to the patients with high-risk factors of fungemia and focus on the drug resistance of non-C. albicans, choose the right antifungal drugs, so as to improve the level of diagnosis and treatment.

Epidemic Changes and Spatio-Temporal Analysis of Japanese Encephalitis in Shaanxi Province, China, 2005-2018.

Japanese encephalitis (JE) is a mosquito-borne viral disease, which is the most serious viral encephalitis in China and other countries of the Asia-Pacific region. Since 2005, the epidemic patterns of JE have changed dramatically in China because of the vaccination of children younger than 15 years old, and JE is expanding geographically along with global warming. This retrospective epidemiological study analyzed dynamic environmental factors and the spatio-temporal distribution of human cases of JE in Shaanxi Province-one of the most severely affected areas of China-from 2005 to 2018. The results demonstrated that the high-risk population changed rapidly as the annual rate of JE cases increased by more than 40% in the age group >60 years during the study period, and endemic areas expanded northward in Shaanxi. Hotspot analysis detected four hotspots accounting for 52.38% the total cases, and the panel negative binomial regression model revealed that the spatio-temporal distribution of JE was significantly affected by temperature, relative humidity, wind velocity, El Niño-Southern Oscillation, coniferous forest coverage, and urban areas. These findings can provide useful information for improving current strategies and measures to reduce disease incidence.

Estimating length of stay and inpatient charges attributable to hospital-acquired bloodstream infections.

BACKGROUND: Hospital-acquired bloodstream infection (BSI) is associated with high morbidity and mortality and increases patients' length of stay (LOS) and hospital charges. Our goals were to calculate LOS and charges attributable to BSI and compare results among different models. METHODS: A retrospective observational cohort study was conducted in 2017 in a large general hospital, in Beijing. Using patient-level data, we compared the attributable LOS and charges of BSI with three models: 1) conventional non-matching, 2) propensity score matching controlling for the impact of potential confounding variables, and 3) risk set matching controlling for time-varying covariates and matching based on propensity score and infection time. RESULTS: The study included 118,600 patient admissions, 557 (0.47%) with BSI. Six hundred fourteen microorganisms were cultured from patients with BSI. Escherichia coli was the most common bacteria (106, 17.26%). Among multi-drug resistant bacteria, carbapenem-resistant Acinetobacter baumannii (CRAB) was the most common (42, 38.53%). In the conventional non-matching model, the excess LOS and charges associated with BSI were 25.06 days (P < 0.05) and US$22041.73 (P < 0.05), respectively. After matching, the mean LOS and charges attributable to BSI both decreased. When infection time was incorporated into the risk set matching model, the excess LOS and charges were 16.86 days (P < 0.05) and US$15909.21 (P < 0.05), respectively. CONCLUSION: This is the first study to consider time-dependent bias in estimating excess LOS and charges attributable to BSI in a Chinese hospital setting. We found matching on infection time can reduce bias.

Bloodstream Infection and Its Clinical Characteristics and Relevant Factors Associated with Interventional Therapy in a Large Tertiary Hospital: A Six Years Surveillance Study.

BACKGROUND: Interventional therapy has been widely used in the medical field as its advantages of minimally invasive, safe and quick recovery. Bloodstream infection (BSI) is the most common healthcare-associated infections (HAIs) after interventional therapy, but there are few reports about it. This study intends to analyze the clinical characteristics and relevant factors of BSI after six years of interventional therapy in a large tertiary teaching hospital, in order to provide guidances for the prevention and control of BSI after interventional operations. METHODS: The case information of patients with BSI after interventional therapy from 2013 to 2018 were collected through the "real-time monitoring system of healthcare-associated infections". All BSI was determined by the infection control full-time staff and clinicians. Questionnaires were designed to review case by case and register the relevant patient information into a database. A total of 18 relevant factors were counted. Statistical software was used for analysis. RESULTS: 174 cases of BSI occurred in 25401 patients, the incidence was 0.69%, and BSI accounted for 50% of all infected sites. Gram-positive bacteria accounted for 56.05%, coagulase-negative Staphylococcus was the main infectious bacteria. Relevant risk factor analysis showed that hepatocellular carcinoma, had undergone surgery, biliary complications, prophylactic antibiotic, replacement of antibiotics, number of interventional operations, days of prophylactic antibiotic use were the related risk factors associated with BSI (P < 0.05). Multivariate analysis showed that days of prophylactic antibiotic use (OR = 1.586, P < 0.05) and replacement of antibiotics (OR = 13.349, P < 0.05) were the main risk factors associated with the development of BSI. CONCLUSIONS: BSI is the main infection site after interventional surgery. For patients with the risk factors as hepatocellular carcinoma/biliary complications/had undergone surgery etc., the time of prophylactic antibiotic use can be prolonged properly before interventional surgery, and selection of single antibiotic appropriate for use could significantly aid preventive measures to avoid occurrence of BSI.

Incidence of healthcare-associated infections in a tertiary hospital in Beijing, China: results from a real-time surveillance system.

Background: To quantify the five year incidence trend of all healthcare-associated infections (HAI) using a real-time HAI electronic surveillance system in a tertiary hospital in Beijing, China. Methods: The real-time surveillance system scans the hospital's electronic databases related to HAI (e.g. microbiological reports and antibiotics administration) to identify HAI cases. We conducted retrospective secondary analyses of the data exported from the surveillance system for inpatients with all types of HAIs from January 1st 2013 to December 31st 2017. Incidence of HAI is defined as the number of HAIs per 1000 patient-days. We modeled the incidence data using negative binomial regression. Results: In total, 23361 HAI cases were identified from 633990 patients, spanning 6242375 patient-days during the 5-year period. Overall, the adjusted five-year HAI incidence rate had a marginal reduction from 2013 (4.10 per 1000 patient days) to 2017 (3.62 per 1000 patient days). The incidence of respiratory tract infection decreased significantly. However, the incidence rate of bloodstream infections and surgical site infection increased significantly. Respiratory tract infection (43.80%) accounted for the most substantial proportion of HAIs, followed by bloodstream infections (15.74%), and urinary tract infection (12.69%). A summer peak in HAIs was detected among adult and elderly patients. Conclusions: This study shows how continuous electronic incidence surveillance based on existing hospital electronic databases can provide a practical means of measuring hospital-wide HAI incidence. The estimated incidence trends demonstrate the necessity for improved infection control measures related to bloodstream infections, ventilator-associated pneumonia, non-intensive care patients, and non-device-associated HAIs, especially during summer months.

The Minimum Data Set and Quality Indicators for National Healthcare-Associated Infection Surveillance in Mainland China: Towards Precision Management.

The magnitude and scope of the healthcare-associated infections (HCAIs) burden are underestimated worldwide, and have raised public concerns for their adverse effect on patient safety. In China, HCAIs still present an unneglected challenge and economic burden in recent decades. With the purpose of reducing the HCAI prevalence and enhancing precision management, China's National Nosocomial Infection Management and Quality Control Center (NNIMQCC) had developed a Minimum Data Set (MDS) and corresponding Quality Indicators (QIs) for establishing national HCAI surveillance system, the data elements of which were repeatedly discussed, investigated, and confirmed by consensus of the expert team. The total number of data elements in MDS and QIs were 70 and 64, and they were both classified into seven categorical items. The NNIMQCC also had started two pilot projects to inspect the applicability, feasibility, and reliability of MDS. After years of hard work, more than 400 health facilities in 14 provinces have realized the importance of HCAI surveillance and contributed to developing an ability of exporting automatically standardized data to meet the requirement of MDS and participate in the regional surveillance system. Generally, the emergence of MDS and QIs in China indicates the beginning of the national HCAI surveillance based on information technology and computerized process data. The establishment of MDS aimed to use electronic health process data to ensure the data accuracy and comparability and to provide instructive and ongoing QIs to estimate and monitor the burden of HCAIs, and to evaluate the effects of interventions and direct health policy decision-making.

The scrub typhus in mainland China: spatiotemporal expansion and risk prediction underpinned by complex factors.

In mainland China, a geographic northward expansion of scrub typhus has been seen, highlighting the need to understand the factors and identify the risk for disease prevention. Incidence data from 1980 to 2013 were used. A Cox proportional hazard model was used to identify drivers for spatial spread, and a boosted regression tree (BRT) model was constructed to predict potential risk areas. Since the 1980s, an invasive expansion from South Natural Foci towards North Natural Foci was clearly identified, with the epidemiological heterogeneity observed between two regions, mainly in spatial distribution, seasonality, and demographic characteristics. Survival analysis disclosed significant factors contributing to the spatial expansion as following: being intersected by freeway (HR = 1.31, 95% CI: 1.11-1.54), coverage percentage of broadleaf forest (HR = 1.10, 95% CI: 1.06-1.15), and monthly average temperature (HR = 1.27, 95% CI: 1.25-1.30). The BRT models showed that precipitation, sunshine hour, temperature, crop field, and relative humidity contributed substantially to the spatial distribution of scrub typhus. A county-scale risk map was created to predict the regions with high probability of the disease. The current study enabled a comprehensive overview of epidemiological characteristics of scrub typhus in mainland China.

Wide Distribution and Genetic Diversity of Babesia microti in Small Mammals from Yunnan Province, Southwestern China.

BACKGROUND: Babesia, usually found in wild and domestic mammals worldwide, have recently been responsible for emerging malaria-like zoonosis in infected patients. Human B. microti infection has been identified in China, primarily in the Southwest along the Myanmar border but little direct surveillance of B. microti infection in rodents has been carried out here (Yunnan province). In this region, a diverse topographic range combined with tropical moisture sustains a high biodiversity of small mammals, which might play important role on Babesia transmission. METHODS: Small mammals were captured in 141 sample locations from 18 counties located Yunnan Province, and screened for B. microti-like parasites infection by a nested PCR to target 18S rRNA gene of Babesia, plus directly sequencing for positive samples. Univariate and multivariate forward stepwise logistic regression analysis was used to access the association between infections and some related risk factors. RESULTS: Infection with Babesia microti was confirmed in 2.4% (53/ 2204) of small mammals. Significant differences in prevalence rates of B. microti were observed based on variations in forest, agricultural, and residential landscapes. Furthermore, adult small mammals had higher prevalence rates than younger, pubertal mammals. The near full-length 18S rRNA gene revealed that there were two types of B. microti, Kobe and Otsu, which demonstrate the genetic diversity and regional distribution. CONCLUSIONS: There exists a wide distribution and genetic diversity of endemic B. microti in Southwestern China, warranting further investigations and monitoring of clinical disease in individuals presenting with Babesia like symptoms in these areas.

Mapping the clinical outcomes and genetic evolution of Ebola virus in Sierra Leone.

Sierra Leone was the most severely affected country in Western Africa during the 2013-2016 outbreak of Ebola virus disease (EVD). Previous genome surveillance studies have revealed the origin, diversity, and evolutionary dynamics of the Ebola virus (EBOV); however, the information regarding EBOV sequences is insufficient, especially the clinical outcomes, given that the correlation between the clinical outcomes and the genetic evolution of EBOV is still not clear. Here, we collected and curated a comprehensive data set that includes 514 EBOV genome sequences from patients with confirmed EVD (including 60 sequences not previously studied), >87.5% of which have residence information and definitive clinical outcomes. Phylogenetic reconstruction revealed 11 lineages of EBOV in Sierra Leone. The median-joining haplotype network showed that haplotypes that are associated with lethal outcomes tend to contribute more to the spread of the EBOV in Sierra Leone than those with live outcomes. Analyses of the spatial-temporal distribution unraveled the lineage-distinctive distribution patterns. Different viral lineages have different case fatality rates (CFRs) during the same stage of the outbreak, implying that several lineages featuring SNPs may correlate with increased/decreased CFRs. This study provides invaluable data sets of EBOV infection and highlights the potential SNPs for further in-depth investigation.

Mapping the distribution of tick-borne encephalitis in mainland China.

Tick-borne encephalitis (TBE) has become an increasing public health threat in recent years, ranging from Europe, through far-eastern Russia to Japan and northern China. However, the neglect of its expansion and scarce analyses of the dynamics have made the overall disease burden and the risk distribution of the disease being unclear in mainland China. In this study, we described epidemiological characteristics of 2117 reported human TBE cases from 2006 to 2013 in mainland China. About 99% of the cases were reported in forest areas of northeastern China, and 93% of reported infections occurred during May-July. Cases were primarily male (67%), mostly in 30-59 years among all age-gender groups. Farmers (31.6%), domestic workers (20.1%) and forest workers (17.9%) accounted for the majority of the patients, and the proportions of patients from farmers and domestic workers were increasing in recent years. The epidemiological features of TBE differed slightly across the affected regions. The distribution and features of the disease in three main endemic areas of mainland China were also summarized. Using the Boosted Regression Trees (BRT) model, we found that the presence of TBE was significantly associated with a composite meteorological index, altitude, the coverage of broad-leaved forest, the coverage of mixed broadleaf-conifer forest, and the distribution of Ixodes persulcatus (I. persulcatus) ticks. The model-predicted probability of presence of human TBE cases in mainland China was mapped at the county level. The spatial distribution of human TBE in China was largely driven by the distributions of forests and I. persulcatus ticks, altitude, and climate. Enhanced surveillance and intervention for human TBE in the high-risk regions, particularly on the forest areas in north-eastern China, is necessary to prevent human infections.

Rapid increase of scrub typhus incidence in Guangzhou, southern China, 2006-2014.

BACKGROUND: In the last decade, scrub typhus (ST) has been emerging or re-emerging in some areas of Asia, including Guangzhou, one of the most affected endemic areas of ST in China. METHODS: Based on the data on all cases reported in Guangzhou from 2006 to 2014, we characterized the epidemiological features, and identified environmental determinants for the spatial distribution of ST using a panel negative binomial model. RESULTS: A total of 4821 scrub typhus cases were reported in Guangzhou during 2006-2014. The annual incidence increased noticeably and the increase was relatively high and rapid in rural townships and among elderly females. The majority of cases (86.8%) occurred during May-October, and farmers constituted the majority of the cases, accounting for 33.9% in urban and 61.6% in rural areas. The number of housekeeper patients had a rapid increment in both rural and urban areas during the study period. Atmospheric pressure and relative humidity with lags of 1 or 2 months, distributions of broadleaved forest and rural township were identified as determinants for the spatiotemporal distribution of scrub typhus. CONCLUSION: Our results indicate that surveillance and public education need to be focused on the elderly farmers in rural areas covered with broadleaf forest in southern China.

Transmission dynamics of Ebola virus disease and intervention effectiveness in Sierra Leone.

Sierra Leone is the most severely affected country by an unprecedented outbreak of Ebola virus disease (EVD) in West Africa. Although successfully contained, the transmission dynamics of EVD and the impact of interventions in the country remain unclear. We established a database of confirmed and suspected EVD cases from May 2014 to September 2015 in Sierra Leone and mapped the spatiotemporal distribution of cases at the chiefdom level. A Poisson transmission model revealed that the transmissibility at the chiefdom level, estimated as the average number of secondary infections caused by a patient per week, was reduced by 43% [95% confidence interval (CI): 30%, 52%] after October 2014, when the strategic plan of the United Nations Mission for Emergency Ebola Response was initiated, and by 65% (95% CI: 57%, 71%) after the end of December 2014, when 100% case isolation and safe burials were essentially achieved, both compared with before October 2014. Population density, proximity to Ebola treatment centers, cropland coverage, and atmospheric temperature were associated with EVD transmission. The household secondary attack rate (SAR) was estimated to be 0.059 (95% CI: 0.050, 0.070) for the overall outbreak. The household SAR was reduced by 82%, from 0.093 to 0.017, after the nationwide campaign to achieve 100% case isolation and safe burials had been conducted. This study provides a complete overview of the transmission dynamics of the 2014-2015 EVD outbreak in Sierra Leone at both chiefdom and household levels. The interventions implemented in Sierra Leone seem effective in containing the epidemic, particularly in interrupting household transmission.

Mapping the Distribution of Anthrax in Mainland China, 2005-2013.

BACKGROUND: Anthrax, a global re-emerging zoonotic disease in recent years is enzootic in mainland China. Despite its significance to the public health, spatiotemporal distributions of the disease in human and livestock and its potential driving factors remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Using the national surveillance data of human and livestock anthrax from 2005 to 2013, we conducted a retrospective epidemiological study and risk assessment of anthrax in mainland China. The potential determinants for the temporal and spatial distributions of human anthrax were also explored. We found that the majority of human anthrax cases were located in six provinces in western and northeastern China, and five clustering areas with higher incidences were identified. The disease mostly peaked in July or August, and males aged 30-49 years had higher incidence than other subgroups. Monthly incidence of human anthrax was positively correlated with monthly average temperature, relative humidity and monthly accumulative rainfall with lags of 0-2 months. A boosted regression trees (BRT) model at the county level reveals that densities of cattle, sheep and human, coverage of meadow, coverage of typical grassland, elevation, coverage of topsoil with pH > 6.1, concentration of organic carbon in topsoil, and the meteorological factors have contributed substantially to the spatial distribution of the disease. The model-predicted probability of occurrence of human cases in mainland China was mapped at the county level. CONCLUSIONS/SIGNIFICANCE: Anthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections.

Risk Distribution of Human Infections with Avian Influenza H7N9 and H5N1 virus in China.

It has been documented that the epidemiological characteristics of human infections with H7N9 differ significantly between H5N1. However, potential factors that may explain the different spatial distributions remain unexplored. We use boosted regression tree (BRT) models to explore the association of agro-ecological, environmental and meteorological variables with the occurrence of human cases of H7N9 and H5N1, and map the probabilities of occurrence of human cases. Live poultry markets, density of human, coverage of built-up land, relative humidity and precipitation were significant predictors for both. In addition, density of poultry, coverage of shrub and temperature played important roles for human H7N9 infection, whereas human H5N1 infection was associated with coverage of forest and water body. Based on the risks and distribution of ecological characteristics which may facilitate the circulation of the two viruses, we found Yangtze River Delta and Pearl River Delta, along with a few spots on the southeast coastline, to be the high risk areas for H7N9 and H5N1. Additional, H5N1 risk spots were identified in eastern Sichuan and southern Yunnan Provinces. Surveillance of the two viruses needs to be enhanced in these high risk areas to reduce the risk of future epidemics of avian influenza in China.

Nosocomial transmission of avian influenza A (H7N9) virus in China: epidemiological investigation.

STUDY QUESTION: Can avian influenza A (H7N9) virus be transmitted between unrelated individuals in a hospital setting? METHODS: An epidemiological investigation looked at two patients who shared a hospital ward in February 2015, in Quzhou, Zhejiang Province, China. Samples from the patients, close contacts, and local environments were examined by real time reverse transcriptase (rRT) polymerase chain reaction (PCR) and viral culture. Haemagglutination inhibition and microneutralisation assays were used to detect specific antibodies to the viruses. Primary outcomes were clinical data, infection source tracing, phylogenetic tree analysis, and serological results. STUDY ANSWER AND LIMITATIONS: A 49 year old man (index patient) became ill seven days after visiting a live poultry market. A 57 year old man (second patient), with a history of chronic obstructive pulmonary disease, developed influenza-like symptoms after sharing the same hospital ward as the index patient for five days. The second patient had not visited any poultry markets nor had any contact with poultry or birds within 15 days before the onset of illness. H7N9 virus was identified in the two patients, who both later died. Genome sequences of the virus isolated from both patients were nearly identical, and genetically similar to the virus isolated from the live poultry market. No specific antibodies were detected among 38 close contacts. Transmission between the patients remains unclear, owing to the lack of samples collected from their shared hospital ward. Although several environmental swabs were positive for H7N9 by rRT-PCR, no virus was cultured. Owing to delayed diagnosis and frequent hospital transfers, no serum samples were collected from the patients, and antibodies to H7N9 viruses could not be tested. WHAT THIS STUDY ADDS: Nosocomial H7N9 transmission might be possible between two unrelated individuals. Surveillance on patients with influenza-like illness in hospitals as well as chickens in live poultry markets should be enhanced to monitor transmissibility and pathogenicity of the virus. FUNDING, COMPETING INTERESTS, DATA SHARING: Funding support from the Program of International Science and Technology Cooperation of China (2013DFA30800), Basic Work on Special Program for Science and Technology Research (2013FY114600), National Natural Science Foundation of China (81402730), Special Program for Prevention and Control of Infectious Diseases in China (2013ZX10004218), US National Institutes of Health (1R01-AI108993), Zhejiang Province Major Science and Technology Program (2014C03039), and Quzhou Science and Technology Program (20111084). The authors declare no other interests and have no additional data.