Global research landscape and trends of lung cancer immunotherapy: A bibliometric analysis.

​Background: Immunotherapy for lung cancer has been a hot research area for years. This bibliometric analysis aims to present the research trends on lung cancer immunotherapy. Method: On 1 July, 2022, the authors identified 2,941 papers on lung cancer immunotherapy by the Web of Science and extracted their general information and the total number of citations. A bibliometric analysis was carried out to present the research landscape, demonstrate the research trends, and determine the most cited papers (top papers) as well as major journals on lung cancer immunotherapy. After that, recent research hotspots were analyzed based on the latest publications in major journals. Results: These 2,941 papers were cited a total of 122,467 times. "Nivolumab vs. docetaxel in advanced non-squamous non-small-cell lung cancer" published in 2015 by Borghaei H et al. was the most cited paper (5,854 citations). Among the journals, New England Journal of Medicine was most influential. Corresponding authors represented China took part in most articles (904) and papers with corresponding authors from the USA were most cited (139.46 citations per paper). Since 2015, anti-PD-(L)1 has become the hottest research area. Conclusions: This bibliometric analysis comprehensively and quantitatively presents the research trends and hotspots based on thousands of publications, and further suggests future research directions. Moreover, the results can benefit researchers to select journals and find potential collaborators. This study can help researchers get a comprehensive impression of the research landscape, historical development, and recent hotspots in lung cancer immunotherapy and provide inspiration for further research.

Directional growth of quasi-2D Cu2O monocrystals on rGO membranes in aqueous environments.

The preparation technology of unconventional low-dimensional Cu2O monocrystals, which exhibit specific crystal planes and present significantly unique interfacial and physicochemical properties, is attracting increasing attention and interest. Herein, by integrating a high-temperature oxidation process under vacuum and a pure-water incubation process under ambient conditions, we propose the self-assembled growth and synthesis of quasi-two-dimensional Cu2O monocrystals on reduced graphene oxide (rGO) membranes. The prepared Cu2O crystals have a single (110) crystal plane, regular rectangular morphology, and potentially well conductivity. Experimental and theoretical results suggest that this assembly is attributed to the pre-nucleation clusters aggregation and directional attachment of Cu and O on the rGO membranes in aqueous environment and cation-π interactions between the (110) crystal plane of Cu2O and rGO surface. Our findings offer a potential avenue for the discovery and design of advanced low-dimensional single-crystal materials with specific interfacial properties in a pure aqueous environment.

Dramatic response to local radiotherapy in a refractory metastatic mediastinal yolk sac tumor patient harboring a germline BRCA2 frameshift mutation: a case report.

Mediastinal yolk sac tumors (YSTs) are highly aggressive germ cell tumors with an extremely poor prognosis. Radiotherapy plays an important role in the treatment of mediastinal YSTs. To maximize benefit from radiotherapy in patients with mediastinal YSTs, exploring functionally relevant biomarkers is essential. Previous studies have demonstrated that mutations in DNA-damage repair (DDR) genes, including BRCA1/2, potentially enhance sensitivity to radiotherapy in solid tumors. However, DDR-gene mutations, as possible predictive biomarkers for radiotherapy in primary mediastinal YSTs, have not yet been reported. Herein, we report a 29-year-old male patient with a refractory metastatic primary YST involving a germline frameshift mutation in the BRCA2 gene (NM_000059.3: exon11: c.4563_4564delAT: L1522fs). During treatment alternation, the patient was found to respond poorly to chemotherapy with or without an immune checkpoint inhibitor but well to radiotherapy. Finally, the patient achieved approximately 17 months of overall survival. To the best of our knowledge, this case report is the first to describe a remarkable response to local radiotherapy in a patient with a refractory metastatic mediastinal YST involving a DDR-gene mutation (germline BRCA2 frameshift variation). This case report provides insightful clues for precision radiotherapy in clinical practice.

[A Case Report of Checkpoint Inhibitor Pneumonitis Caused by PD-1
Antibody-Safety and Effectiveness of Pirfenidone].

BACKGROUND: Immune checkpoint inhibitor associated pneumonia (CIP) is a serious side effect of immune checkpoint inhibitors. There is a consensus on the treatment of acute phase of CIP, but the treatment of pulmonary interstitial fibrosis after the acute phase is still a clinical problem to be solved. METHODS: The diagnosis and treatment of a non-small cell lung cancer (NSCLC) patient with immune checkpoint inhibitor associated pneumonia in the Stereotactic Radiotherapy Department of Qingdao Central Hospital were retrospectively analyzed, and literatures were reviewed. RESULTS: A 70-year-old male patient was diagnosed with Poorly differentiated squamous cell carcinoma of left lung with mediastinal lymph node metastasis T3N3M0 stage IIIc, EGFR/ALK/ROS1/RAF negative, PD-L1 (22c3) immunohistochemistry negative. After the progression of first-line chemotherapy, the patient was diagnosed as immune checkpoint inhibitor associated pneumonia grade 3 during second-line monotherapy with Nivolumab. After initial high-dose glucocorticoid pulse therapy, the lung computed tomography (CT) imaging and clinical symptoms of the patients were partially relieved, and then pirfenidone (300 mg tid) was given orally for more than 11 months. During the treatment of pirfenidone, the CT imaging and clinical symptoms of the patients were significantly improved, and there were no other adverse reactions except grade 1 nausea. During this period, chemotherapy and Anlotinib was given concurrently with pirfenidone and showed good safety profile. CONCLUSIONS: This case report is the first report of pirfenidone in the treatment of CIP, which provides a new idea for the clinical practice and research of CIP treatment.

A case report of complete pathological remission after chemotherapy in a patient with primary renal squamous cell carcinoma.

This is the first case report of the outcomes of systemic chemotherapy in a patient with locally advanced renal squamous cell carcinoma, a rare tumor, as well as the first next generation sequencing study of this rare tumor. The patient's main symptoms were fever and low back pain. Initial positron emission tomography and computed tomography (PET-CT) suggested a malignant renal tumor at onset, but biopsy confirmed renal squamous cell carcinoma. Next generation sequencing showed a low level of microsatellite instability (MSI-L), a high tumor mutational burden (TMB-H), a high neoantigen burden (TNB-H), and a strong loss of heterozygosity (LOH) for human leukocyte antigen (HLA), with 67 deleterious mutations. The patient achieved partial radiological remission after a cycle of systemic chemotherapy with albumin-bound paclitaxel combined with nedaplatin. After radical resection of the left renal tumor, postoperative pathology confirmed complete tumor remission and tumor-like xanthogranulomatous pyelonephritis. Conclusion: This renal squamous cell carcinoma patient responded to systemic chemotherapy with paclitaxel combined with platinum, providing a reference for the future treatment of similar cases. Pathology and gene sequencing indicated that renal squamous cell carcinoma occurred in a background of active inflammation and that the tumor evolved immune escape mechanisms such as loss of HLA heterozygosity, with gene repair defects and TMB-H.

Co2+-Tuned Tin Oxide Interfaces for Enhanced Stability of Organic Solar Cells.

The electron transport layers (ETLs) are one of the crucial factors for realizing the high performance of inverted organic solar cells (OSCs). In inverted OSCs, zinc oxide (ZnO) is a widely used n-type semiconductor as the ETL material. However, when exposed to ultraviolet (UV) light, ZnO induces decomposition of organic materials. Tin dioxide (SnO2) has higher conductivity, higher electron mobility, wider bandgap, and weaker absorption of UV light, which is thought to be one of the promising ETLs. Unfortunately, a SnO2 ETL is suffering from high work function (WF), which greatly decreases the ability of charge transport and collection. Here, we induce a facile strategy to reduce the WF of SnO2 by Co2+ tuning. The Co2+-tuned SnO2 exhibits a low WF of 3.64 eV, holding high transmittance and high conductivity. The OSCs based on PM6:Y6 with a Co2+-SnO2 ETL show a notable power conversion efficiency of 15.3%, which is superior to those of the OSCs with ZnO and SnO2 ETLs. The OSCs with a Co2+-SnO2 ETL under continuous UV light and light-emitting diode irradiation exhibit a more robust photostability relative to OSCs with pristine SnO2 ETLs. The trap densities of Co2+-SnO2 films are lower than that of the SnO2 film, which may contribute to enhanced stability of OSCs.

Intestine-targeted delivery potency of the O-carboxymethyl chitosan-gum Arabic coacervate: Effects of coacervation acidity and possible mechanism.

The potential of the glutaraldehyde-crosslinked O-carboxymethyl chitosan (O-CMC)-gum Arabic (GA) coacervate as an intestine-targeted delivery system for hydrophobic compounds was concerned. OCMC-GA coacervates and emulsified bovine serum albumin (BSA)-loaded microcapsules were prepared in pH3.0, 4.5, and 6.0 and their swelling behaviors as well as BSA release profiles in simulated gastrointestinal fluids were measured. All the coacervates showed higher swelling ratios in the simulated gastric solution than in the simulated intestine and colon solutions and the values increased as the coacervation pH increased from 3.0 to 6.0, but a reversed trend was observed for the BSA release profile. SEM, TEM, and CLSM analysis revealed that the coacervation acidity influenced the swelling and BSA release behavior by changing the matrix density and O-CMC content of the coacervates. It was concluded that the O-CMC-GA coacervate could be used to deliver hydrophobic compounds to the intestine and its delivery performance could be tailored by selecting appropriate coacervation acidity and crosslinking degree.

Competitive adsorption desulfurization performance over K - Doped NiY zeolite.

NiY and KNiY were successfully prepared by impregnation method and characterized by X-ray diffraction (XRD), N2 sorption (BET), scanning electron microscope (SEM), infrared spectrum (IR) and X-ray Photoelectron Spectroscopy (XPS). The competitive adsorption mechanisms of adsorbents were studied by in situ FTIR to explain different desulfurization performance which was evaluated in a miniature fixed-bed flow by gasoline model compounds with 1-hexene or toluene. NiY and KNiY adsorbents showed better desulfurization performance than HY zeolite due to the high selectivity of loaded active metals. Especially, KNiY adsorbent showed its advantages in desulfurization performance with 5vol% olefins or 5vol% aromatics involvement. It could be assigned that introduced K cation enhanced dispersion and content of active Ni species on the surface which made Ni species reduce easily. On the other hand, adsorption mechanisms showed that the protonation reactions of thiophene and 1-hexene occurred on the Brönsted acid sites of NiY, which resulted in pore blockage and the coverage of adsorption active centers. By doping K cation on NiY, the amount of the Brönsted acid sites of NiY was decreased and protonation reactions were weaken. Therefore, the negative effects of Brönsted acid sites were reduced.

Genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate as a pH-sensitive delivery system and microstructure characterization.

The possibility of genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate as a pH-sensitive delivery vehicle was investigated. O-carboxymethyl chitosan-gum Arabic coacervates separated in pH 3.0, 4.5, and 6.0 were crosslinked by genipin for different durations and the crosslinked products were subjected to crosslinking degree, swelling behavior, bovine serum albumin release profile, and microstructure characterization. Genipin-crosslinking greatly improved the stability of the coacervates against the simulated gastric solution and created certain pH-sensitivity. The coacervates displayed higher swelling ratios in the simulated gastric solution than in the simulated intestine and colon solutions; meanwhile, the coacervates prepared in pH 4.5 and 6.0 swelled more severely than the complex separated in pH 3.0. Nevertheless, the bovine serum albumin release in the simulated gastric solution from the microcapsules prepared in pH 6.0 was much lower than those prepared in pH 4.5 and 3.0, whose cumulative release percentages in the three simulated solutions were 17.14%, 55.23%, and 79.79%, respectively, in crosslinking duration 2 h. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analysis revealed that genipin-crosslinking improved the regularity and compactness of coacervate structure, whereas confocal laser scanning microscopy observation indicated that O-carboxymethyl chitosan content was possibly the major reason for the different swelling and bovine serum albumin release behavior of the coacervates. It was concluded that the genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate was a potential intestine-targeted delivery system and its delivery performance could be tailored by varying the crosslinking degree and coacervation acidity.

Comprehensive Understanding of High Polar Polyacrylonitrile as an Effective Binder for Li-Ion Battery Nano-Si Anodes.

Well-defined polyacrylonitriles (PANs) with different molecular weights were synthesized through an activator regenerated by electron-transfer atom-transfer radical polymerization method and employed as binders in silicon negative electrode for lithium-ion batteries. Compared with poly(vinylidene fluoride) and carboxyl methyl cellulose as binders, the electrode performance of PANs is well-improved. Specifically, at 100 mA g(-1) from 0.01 to 1.5 V, the initial discharge capacity of PAN100-based electrode is 4147.8 mA h g(-1) and still remains about 1639.6 mA h g(-1) over 50 cycles. A comprehensive understanding on the improvement mechanism is preliminarily discussed. The results indicate that the superior performance largely depends on the higher lithium ion diffusion efficiency in PAN which results from the weak interaction between lithium ions and PAN polymer chain, and the hydrogen bonds among the nitrile group (C≡N) of PAN, Si nanoparticles, and the current collector, which will lead to an efficient coating of PAN with the Si particles and well-improved adhesion strength, synergistically depressing the structural deterioration of silicon electrodes.

Up-regulated miR-155-5p promotes cell proliferation, invasion and metastasis in colorectal carcinoma.

BACKGROUND AND OBJECTIVE: Emerging evidences indicate that miR-155-5p is associated with some cancer tumorigenesis, but their specific effects on proliferation, invasion and metastasis of colorectal carcinoma (CRC) are still poorly understood. The aim of the study is to investigate miR-155-5p effect on proliferation and invasion metastasis of CRC. METHODS: Retrospectively analyzed clinicopathological parameters and fresh tissue samples of 372 colon cancer patients receiving radical surgery. HT-29 cells were transfected with mimics and inhibitors of miR-155-5p, respectively. Real-time reverse transcription-PCR was performed to measure miR-155-5p relative levels of tissues and cells. RESULTS: miR-155-5p expression in cancer group was higher than that in normal group, with statistical differences (P<0.05). miR-155-5p expression was associated with tumor location, tumor grade, TNM staging and distant metastasis (P<0.05 for all parameters). Cell number of mimics group was higher than control group (P<0.01), and that of inhibitor group was lower than control group (P<0.05). Invasion and metastasis effect of mimics group were the highest and those of inhibitor group were the lowest. CONCLUSIONS: miR-155-5p expression is up-regulated in most CRC and promotes proliferation, invasion and metastasis of CRC cells. It may play an essential role in tumorigenesis and tumor progression of CRC.

Prognostic significance of preoperative fibrinogen in patients with colon cancer.

AIM: To investigate the prognostic significance of preoperative fibrinogen levels in colon cancer patients. METHODS: A total of 255 colon cancer patients treated at the Affiliated Tumor Hospital of Xinjiang Medical University from June 1(st) 2005 to June 1(st) 2008 were enrolled in the study. All patients received radical surgery as their primary treatment method. Preoperative fibrinogen was detected by the Clauss method, and all patients were followed up after surgery. Preoperative fibrinogen measurements were correlated with a number of clinicopathological parameters using the Student t test and analysis of variance. Survival analyses were performed by the Kaplan-Meier method and Cox regression modeling to measure 5-year disease-free survival (DFS) and overall survival (OS). RESULTS: The mean preoperative fibrinogen concentration of all colon cancer patients was 3.17 ± 0.88 g/L. Statistically significant differences were found between preoperative fibrinogen levels and the clinicopathological parameters of age, smoking status, tumor size, tumor location, tumor-node-metastasis (TNM) stage, modified Glasgow prognostic scores (mGPS), white blood cell (WBC) count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and carcinoembryonic antigen (CEA) levels. Univariate survival analysis showed that TNM stage, tumor cell differentiation grade, vascular invasion, mGPS score, preoperative fibrinogen, WBC, NLR, PLR and CEA all correlated with both OS and DFS. Alpha-fetoprotein (AFP) and body mass index correlated only with OS. Kaplan-Meier analysis revealed that both OS and DFS of the total cohort, as well as of the stage II and III patients, were higher in the hypofibrinogen group compared to the hyperfibrinogen group (all P < 0.05). In contrast, there was no significant difference between OS and DFS in stage I patients with low or high fibrinogen levels. Cox regression analysis indicated preoperative fibrinogen levels, TNM stage, mGPS score, CEA, and AFP levels correlated with both OS and DFS. CONCLUSION: Preoperative fibrinogen levels can serve as an independent prognostic marker to evaluate patient response to colon cancer treatment.

New triterpenoids and other constituents from the fruits of Benincasa hispida (Thunb.) Cogn.

Benincasa hispida (Thunb.) Cogn. fruits are widely consumed in China and tropical countries. This study identifies three new triterpenoids, 3α,29-O-di-trans-cinnamoyl-D:C-friedooleana-7,9(11)-diene (1), oleanolic acid 28-O-ß-d-xylopyranosyl-[ß-d-xylopyranosyl-(1→4)]-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (2), and oleanolic acid 28-O-ß-d-glucopyranosyl-(1→3)-ß-d-xylopyranosyl-[ß-d-xylopyranosyl-(1→4)]-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (3), together with 12 known compounds, multiflorenol (4), isomultiflorenyl acetate (5), stigmasterol (6), stigmasterol 3-O-ß-d-glucopyranoside (7), α-spinasterol (8), α-spinasterol 3-O-ß-d-glucopyranoside (9), ß-sitosterol (10), daucosterol (11), arbutin (12), nicotinic acid (13), (+)-pinonesinol (14), and ethyl ß-d-glucopyranoside (15). The structures of compounds 1-15 were determined by spectroscopic and chemical methods. All the compounds with the exception of 4, 5, and 9-11 were isolated from B. hispida for the first time. The anticomplement activities of compounds 1-15 were assessed by Mayer's modified method. Compounds 1-15 showed no significant cytotoxic activity against HeLa human cervical, HL-60 human hepatoma, and SMMC-7721 human hepatoma cell lines.

No evidence of over-reporting of SARS in mainland China.

OBJECTIVE: To find out whether there was over-reporting of SARS patients in mainland China in view of the relatively low case fatality ratio in mainland China, in comparison with other affected countries and areas. METHODS: We searched PubMed for all SARS antibody detection papers (in English or Chinese language) using the keywords 'SARS' and 'antibody'. Then the resulting articles were further read through to select the SARS detection results using ELISA methods of serum samples collected at least 1 month after disease onset. A multi-level logistic regression was applied to test for possible differences in the proportions positive between locations of the study. RESULTS: A total of 48 studies were identified, including 39 from mainland China and nine from elsewhere (Hong Kong, Taiwan, Canada and Vietnam). For mainland China, there was no difference between Guangdong, Beijing and other provinces in the proportions testing positive (83.0%, 85.8% and 85.4% respectively). The grand average of 84.2% seropositive was lower than the 95.1% for the countries and areas outside of mainland China combined. However, this difference was far from significant after correcting for dependency of individual tests within the same study. CONCLUSIONS: Our study showed no evidence of over-reporting of SARS in mainland China, nor in Guangdong, where the SARS epidemic started. Even if the lower seroprevalence in mainland China, relative to other affected areas, does represent actual over-reporting, then this factor can only explain a modest 10% of the lower case fatality in mainland China.

Mathematical modelling of SARS and other infectious diseases in China: a review.

OBJECTIVE: To give an overview of the recent history of publications on mathematical modelling of infectious diseases in the Chinese literature, and a more detailed review of the models on severe acute respiratory syndrome (SARS). METHOD: Literature review through the Chinese CAJ full-text database. RESULTS: The number of Chinese publications on mathematical modelling has at least quadrupled since the SARS epidemic in 2003. This increase not only included papers on SARS, but also on various other infectious diseases, indicating a substantial expansion of modelling experience in China. Typical problems of most studies were poor availability of data and lack of involvement of disease experts and decision-makers rendering the studies less useful for policies on control. CONCLUSIONS: We expect that the recent experience on modelling and current better access to and exchange of epidemiological data have paved the way for a more substantial role of this discipline during possible future outbreaks of infectious diseases. By making Chinese modelling initiatives more visible to non-Chinese readers, we hope to attract more international collaborators.

Duration of symptom onset to hospital admission and admission to discharge or death in SARS in mainland China: a descriptive study.

OBJECTIVE: To describe and analyse factors associated with the duration of disease onset to hospital admission, admission to discharge and admission to death for severe acute respiratory syndrome (SARS), using the recently developed comprehensive database covering all regions of mainland China, and compare the results within and outside China. METHODS: The database included all probable 5327 SARS cases, of whom 343 died. Linear regression (uni- and multivariate analysis) was performed for all three durations to test the impact of the following variables: sex, age, occupation, geographic location and period of the SARS epidemic (time since the first case, i.e. 16 November 2002). RESULTS: The average duration of onset of symptoms to hospital admission was 3.8 days, of admission to discharge for those who survived was 29.7 days, while admission to death for casualties was 17.4 days. Health care workers, patients from Tianjin and patients infected towards the end of the epidemic had the shortest duration of onset to admission. Regarding admission to discharge, particularly young patients and patients from Guangdong had the shortest duration. Older age was the sole factor associated with shorter duration of admission to death. CONCLUSIONS: The average duration and pattern (with time of epidemic and age) of onset of symptoms to hospital admission of SARS patients in mainland China were comparable to other affected areas. The duration of hospital admission to discharge was shorter than elsewhere, possibly because of different hospitalisation policies. The duration of hospital admission to death in mainland China, however, appeared to be shorter than in other areas, which is in striking contrast to the much lower case fatality in mainland China.

Case fatality of SARS in mainland China and associated risk factors.

OBJECTIVE: To analyse the case fatality ratio (CFR) and its risk factors for severe acute respiratory syndrome (SARS) in mainland China by using a comprehensive dataset of all probable cases. METHODS: The data of all probable SARS cases were derived from the Infectious Disease Reporting System of the Center of Diseases Control and Hospital Information Systems, during the 2003 epidemic in mainland China. The definition of probable SARS case was consistent with the definition for clinically confirmed SARS issued by the Ministry of Health of the People's Republic of China. We performed univariate and multivariate logistic regression analysis to determine the association of CFR with age, sex, residence location, occupation, the period of the epidemic and the duration from symptom onset to admission into hospital. RESULTS: The overall CFR was 6.4% among 5327 probable SARS cases in mainland China. Old age, being a patient during the early period of a local outbreak, and being from Tianjin led to a relatively higher CFR than young age, late stage of a local outbreak and cases from Beijing. Guangdong Province resulted in an even lower CFR compared with Beijing. CONCLUSIONS: Because of their deteriorated health status and apparent complications, SARS patients aged >60 years had a much higher risk of dying than younger patients. At the early stage of local outbreaks, lack of experience in patient care and perhaps treatment also led to a relatively higher CFR. The Tianjin SARS outbreak happened mainly within a hospital, leading to a high impact of co-morbidity. The relatively young age of the cases partly explains the low CFR in mainland China compared with other countries and areas affected by SARS.

The SARS epidemic in mainland China: bringing together all epidemiological data.

OBJECTIVE: To document and verify the number of cases of severe acute respiratory syndrome (SARS) during the 2002-2003 epidemic in mainland China. METHOD: All existing Chinese SARS data sources were integrated in one final database. This involved removing non-probable and duplicate cases, adding cases at the final stage of the outbreak, and collecting missing information. RESULTS: The resulting database contains a total of 5327 probable SARS cases, of whom 343 died, giving a case fatality ratio (CFR) of 6.4%. While the total number of cases happens to be equal to the original official reports, there are 5 cases overall which did not result in death. When compared with Hong Kong Special Administrative Region of China, China Taiwan, and Singapore, the SARS epidemic in mainland China resulted in a considerably lower CFR, involved relatively younger cases and included fewer health care workers. CONCLUSIONS: To optimise future data collection during large-scale outbreaks of emerging or re-emerging infectious disease, China must further improve the infectious diseases reporting system, enhance collaboration between all levels of disease control, health departments, hospitals and institutes nationally and globally, and train specialized staff working at county centres of disease control.

Spatial analysis of hemorrhagic fever with renal syndrome in China.

BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) is endemic in many provinces with high incidence in mainland China, although integrated intervention measures including rodent control, environment management and vaccination have been implemented for over ten years. In this study, we conducted a geographic information system (GIS)-based spatial analysis on distribution of HFRS cases for the whole country with an objective to inform priority areas for public health planning and resource allocation. METHODS: Annualized average incidence at a county level was calculated using HFRS cases reported during 1994-1998 in mainland China. GIS-based spatial analyses were conducted to detect spatial autocorrelation and clusters of HFRS incidence at the county level throughout the country. RESULTS: Spatial distribution of HFRS cases in mainland China from 1994 to 1998 was mapped at county level in the aspects of crude incidence, excess hazard and spatial smoothed incidence. The spatial distribution of HFRS cases was nonrandom and clustered with a Moran's I = 0.5044 (p = 0.001). Spatial cluster analyses suggested that 26 and 39 areas were at increased risks of HFRS (p < 0.01) with maximum spatial cluster sizes of < or = 20% and < or = 10% of the total population, respectively. CONCLUSION: The application of GIS, together with spatial statistical techniques, provide a means to quantify explicit HFRS risks and to further identify environmental factors responsible for the increasing disease risks. We demonstrate a new perspective of integrating such spatial analysis tools into the epidemiologic study and risk assessment of HFRS.

[Studies on the spatial distribution and environmental factors of highly pathogenic avian influenza in Mainland China, using geographic information system technology].

OBJECTIVE: To analyze the spatial distribution of highly pathogenic avian influenza (HPAI) and to explore environmental factors associated with HPAI using geographic information system (GIS) techniques in Mainland China. METHODS: Databases were set up using the information of HPAI during epidemics in 2004, and linked to digital maps at provincial and county administrative layers in the country through the ArcGIS 8.3 software. Spatial cluster analyses, spatial statistics analyses and tracking analyses on epidemic situation of HPAI were implemented. Environmental factors associated with HPAI were also analyzed on data related to weather, vegetation and migratory birds etc. RESULTS: Findings from spatial cluster analyses showed that high incidence area was centralized in 113.261 degrees ordm; east longitude and 23. 119 degrees ordm; north latitude with a radius of 1090.52 kilometers (relative risk= 2.646, P value= 0.001). Spatial statistical analyses showed that HPAI took place mainly in capital cities of provinces and surrounding areas as well as in the circumference areas of arterial rivers, lakes and seacoasts. Results also showed that HPAI occurrences were associated with low air temperature, high relative humidity and high air pressure as well as with east & central migration routes of migratory birds. The average normalized difference vegetation index was 0.36 +/- 0.11 in epidemic areas of HPAI. CONCLUSION: HPAI was unrandomly distributed and geographically clustered in China.