Enantioselective anti-Dihalogenation of Electron-Deficient Olefin: A Triplet Halo-Radical Pylon Intermediate.

The textbook alkene halogenation reaction establishes straightforward access to vicinal dihaloalkanes. However, a robust catalytic method for dihalogenizing electron-deficient olefins in an enantioselective manner is still under development, and its mechanism remains controversial. Herein, we disclose efficient regio-, anti-diastereo-, and enantioselective dibromination, bromochlorination, and dichlorination reactions of enones catalyzed by a chiral N,N'-dioxide/Yb(OTf)3 complex. With the combination of electrophilic halogen and halide salts as halogenating agents, an array of homo- and heterodihalogenated derivatives is achieved in moderate to good enantioselectivities. Moreover, DFT calculations reveal that a novel triplet halo-radical pylon intermediate is probable in accounting for the exclusive regio- and anti-diastereoselectivity.

Viruses Regulate Microbial Community Assembly Together with Environmental Factors in Acid Mine Drainage.

Viruses are widespread in various ecosystems, and they play important roles in regulating the microbial community via host-virus interactions. Recently, metagenomic studies showed that there are extremely diverse viruses in different environments from the ocean to the human gut, but the influences of viral communities on microbial communities are poorly understood, especially in extreme environments. Here, we used metagenomics to characterize microbial communities and viral communities in acid mine drainage (AMD) and evaluated how viruses shape microbial community constrained by the harsh environments. Our results showed that AMD viral communities are significantly associated with the microbial communities, and viral diversity has positive correlations with microbial diversity. Viral community explained more variations of microbial community composition than environmental factors in AMD of a polymetallic mine. Moreover, we found that viruses harboring adaptive genes regulate a relative abundance of hosts under the modulation of environmental factors, such as pH. We also observed that viral diversity has significant correlations with the global properties of microbial cooccurrence networks, such as modularity. In addition, the results of null modeling analyses revealed that viruses significantly affect microbial community phylogeny and play important roles in regulating ecological processes of community assembly, such as dispersal limitation and homogenous dispersal. Together, these results revealed that AMD viruses are critical forces driving microbial network and community assembly via host-virus interactions. IMPORTANCE Viruses as mobile genetic elements play critical roles in the adaptive evolution of their hosts in extreme environments. However, how viruses further influence microbial community structure and assembly is still unclear. A recent metagenomic study observed diverse viruses unexplored in acid mine drainage, revealing the associations between the viral community and environmental factors. Here, we showed that viruses together with environmental factors can constrain the relative abundance of host and microbial community assembly in AMD of copper mines and polymetallic mines. Our results highlight the importance of viruses in shaping the microbial community from the individual host level to the community level.

Optimizing SCND with carbon-rich hydrolysates from typical organic wastes: Material composition, augmentation performance, microbiome response, and life cycle impact.

The rapid growth of production and consumption has led to severe environmental pollution, creating a major challenge to achieving the United Nations' sustainable development goals (SDGs). To address it, recycling of organic wastes into value-added products is a possible solution. In this work, four typical organic wastes including sewage sludge (SS), chicken manure (CM), food waste (FW), and corn straw (CS) were employed to produce hydrolysates augmenting shortcut nitrification-denitrification (SCND) for nitrogen depletion in wastewater. The hydrolysates were carbon-rich, with total COD (TCOD), soluble COD (SCOD), and volatile fatty acids (VFA) concentrations ranging from 32.5 to 102.7, 5.7 to 48.4, and 2.0-16.5 mg/L, respectively. The most effective nitrogen depletion was obtained in units supplemented with CM and FW hydrolysates, which had reduced average NH3-N concentrations and near-zero TN removal failure rates under legal requirements. The microbial community analysis demonstrated that various functional bacteria from phylum to genus level were detected in all scenarios, which was corroborated by abundant genetic functions involved in nitrogen metabolism. Further, life cycle assessment revealed negative environmental impact on all categories, with an exception of eutrophication potential (EP) with negative values (∼-0.04 kg Phosphate eq.), allowing positive net environmental benefit (NEB). Operational cost analysis revealed that CM and FW are more effective but costlier than SS and CS. Together, these results indicate that, after hydrolysis, organic wastes can be efficient stimulant augmenting SCND performance for nitrogen depletion in wastewater, benefiting the overall environmental impact.

Coinfections in hospitalized patients with severe fever with thrombocytopenia syndrome: A retrospective study.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease with a high case fatality rate. Few studies have been performed on bacterial or fungal coinfections or the effect of antibiotic therapy. A retrospective, observational study was performed to assess the prevalence of bacterial and fungal coinfections in patients hospitalized for SFTSV infection. The most commonly involved microorganisms and the effect of antimicrobial therapy were determined by the site and source of infection. A total of 1201 patients hospitalized with SFTSV infection were included; 359 (29.9%) had microbiologically confirmed infections, comprised of 292 with community-acquired infections (CAIs) and 67 with healthcare-associated infections (HAIs). Death was independently associated with HAIs, with a more significant effect than that observed for CAIs. For bacterial infections, only those acquired in hospitals were associated with fatal outcomes, while fungal infection, whether acquired in hospital or community, was related to an increased risk of fatal outcomes. The infections in the respiratory tract and bloodstream were associated with a higher risk of death than that in the urinary tract. Both antibiotic and antifungal treatments were associated with improved survival for CAIs, while for HAIs, only antibiotic therapy was related to improved survival, and no effect from antifungal therapy was observed. Early administration of glucocorticoids was associated with an increased risk of HAIs. The study provided novel clinical and epidemiological data and revealed risk factors, such as bacterial coinfections, fungal coinfections, infection sources, and treatment strategies associated with SFTS deaths/survival. This report might be helpful in curing SFTS and reducing fatal SFTS.

Investigation of exposure biomarkers in human plasma following differing levels of tobacco-specific N-nitrosamines and nicotine in cigarette smoke.

Tobacco-specific N-nitrosamines (TSNAs) are strong carcinogens widely found in tobacco products, environmental tobacco smoke, lake, and wastewater. The main objective of this study was to investigate the effects of cigarette smoke with different yields of TSNAs (NNK, NNN, NAT, NAB) and nicotine on the levels of biomarkers of exposure in smokers' plasma. Three hundred healthy volunteers were recruited comprising 60 smokers of each of 3 mg, 8 mg and 10 mg ISO tar yield cigarettes and 60 smokers who smoked 10 mg, 8 mg, and 3 mg for 14 days sequentially and 60 non-smokers. All study participants were male, aged from 21 to 45 years old, and were recruited from a same unit in Hebei, China. We measured the levels of NNAL, NAT, NNN, NAB and cotinine in plasma from 240 smokers and 60 non-smokers using a novel method established by online two-dimensional solid phase extraction-liquid chromatography-tandem mass spectrometry. The results showed that NNAL, NAT, NNN, NAB and cotinine in the plasma of smokers smoking cigarette with low TSNAs and nicotine were lower than that with high TSNAs and nicotine. When smokers switched from higher to lower TSNA yields of cigarettes, their plasma NNAL, NAT, NNN, NAB levels significantly decreased. The plasma concentrations of NNAL were significantly correlated with those of cotinine, NNN, NAT and NAB for smokers (p < 0.001). Similarly, the plasma concentrations of cotinine were significantly correlated with those of NNN, NAT and NAB for smokers (p < 0.001). The plasma NNAL, NAT, NNN, NAB and cotinine levels for smokers were significantly higher than those for non-smokers. These findings suggested that the total NNAL, NNN, NAT, NAB and cotinine in plasma were valid and reliable biomarkers for human exposure to TSNAs and nicotine.

Life cycle assessment and cost analysis for copper hydrometallurgy industry in China.

Understanding the environmental and economic impacts of copper hydrometallurgy throughout the whole life cycle is necessary for sustainable development of the copper industry. In this study, the environmental impacts and economic costs throughout the two major copper hydrometallurgical routes in China, including heap leaching and heap-agitation leaching, are analyzed and compared using the life cycle assessment (LCA) and life cycle cost (LCC) technique. The life cycle inventory compiled from the annual statistics of the Muliashi Copper Mine, and the data regarding energy and materials process are based on the GaBi databases. The environmental impacts are quantified into 12 indicators. The results show that compared with heap leaching route, heap-agitation leaching route reduces 36.8% of abiotic depletion potential (ADP elements), but increases over half of cumulative energy demand (CED), marine aquatic ecotoxicity potential (MAETP) and human toxicity potential (HTP). Furthermore, the stage of electrowinning and agitation leaching contributes the largest environmental impact to heap leaching and heap-agitation leaching route, respectively. This is mainly due to huge consumption of electricity and sulfuric acid. The analysis of economic cost reveals that heap leaching route needs internal cost of $3225/t Cu and external cost of $426/t Cu. Compared with heap leaching route, heap-agitation leaching route increased the internal and external cost by 18.9% and 54.2%, respectively. But the economic return from heap-agitation leaching is double that from heap leaching. Together, these results indicate heap-agitation leaching has a larger environmental impact and higher economic benefit than heap leaching, which is helpful for the government to design ecological compensation policies in the balance between ecological environment and economic development.

miRNAs derived from circulating small extracellular vesicles as diagnostic biomarkers for nasopharyngeal carcinoma.

The microRNAs (miRNAs) in circulating small extracellular vesicles (sEVs) have been suggested as potential biomarkers in cancer diagnosis. This study was designed to evaluate the circulating sEV-derived miRNAs as biomarkers for the diagnosis of nasopharyngeal carcinoma (NPC). We compared the miRNA profiles in plasma-derived sEVs between 16 patients with NPC and 5 healthy controls (HCs). A distinct set of miRNAs that were differentially expressed between patients with NPC and HCs was determined by means of integrative bioinformatics approaches. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis revealed that the target genes of the differentially expressed miRNAs (DEMs) were mainly involved in cancer-associated signaling pathways. Seven representative DEMs were selected and further validated in an additional 60 patients with NPC and 40 HCs using quantitative reverse-transcription PCR analysis (qRT-PCR). Receiver operating characteristic (ROC) curve analysis was used to assess the accuracy of the sEV-miRNA-based model for diagnosis. The 3 miRNA-based model, comprising miR-134-5p, miR-205-5p, and miR-409-3p, showed good discriminating power with an area under the curve (AUC) value of 0.88 in the training set and 0.91 in the validation set. Furthermore, the diagnostic model had an excellent classification ability to distinguish patients with NPC at different clinical stages or Epstein-Barr virus infection status from HCs. In conclusion, our findings indicated that sEV-derived miRNA levels were altered in the plasma of patients with NPC in comparison with those in HCs. The model based on the 3 sEV-derived miRNAs could potentially act as an alternative or complementary approach for diagnosing NPC.

Mobile genetic elements mediate the mixotrophic evolution of novel Alicyclobacillus species for acid mine drainage adaptation.

Alicyclobacillus species inhabit diverse environments and have adapted to broad ranges of pH and temperature. However, their adaptive evolutions remain elusive, especially regarding the role of mobile genetic elements (MGEs). Here, we characterized the distributions and functions of MGEs in Alicyclobacillus species across five environments, including acid mine drainage (AMD), beverages, hot springs, sediments, and soils. Nine Alicyclobacillus strains were isolated from AMD and possessed larger genome sizes and more genes than those from other environments. Four AMD strains evolved to be mixotrophic and fell into distinctive clusters in phylogenetic tree. Four types of MGEs including genomic island (GI), insertion sequence (IS), prophage, and integrative and conjugative element (ICE) were widely distributed in Alicyclobacillus species. Further, AMD strains did not possess CRISPR-Cas systems, but had more GI, IS, and ICE, as well as more MGE-associated genes involved in the oxidation of iron and sulfide and the resistance of heavy metal and low temperature. These findings highlight the differences in phenotypes and genotypes between strains isolated from AMD and other environments and the important role of MGEs in rapid environment niche expansions.

Carbon Nanofibers with Embedded Sb2 Se3 Nanoparticles as Highly Reversible Anodes for Na-Ion Batteries.

As a promising candidate for large-scale energy storage, sodium-ion batteries (SIBs) have superiority due to their low cost and abundance as a resource. Herein, homogeneous Sb2 Se3 nanocrystallites embedded in carbon nanofibers (Sb2 Se3 /CNFs) by electrospinning and selenization treatment are prepared. The obtained Sb2 Se3 /CNFs exhibit good cycling performance, high reversible capacity, and excellent rate capability as anodes for SIBs. The outstanding performances are attributed to a combination of Na+ intercalation, conversion reaction, and alloying with Sb2 Se3 , disclosed through in-situ X-ray diffraction. Meanwhile, unique nanostructures provide large contact surface and tolerant accommodation to volume expansion which bring high reversibility and long cycle durability. This distinctive material shows prospective applications of SIBs especially under high current density.

Candidatus Rickettsia xinyangensis as Cause of Spotted Fever Group Rickettsiosis, Xinyang, China, 2015.

In 2015, we evaluated 221 patients with undifferentiated fever and tick bite or animal exposure in Xinyang, China, for Rickettsia infection. Three with mild disease were infected with Candidatus R. xinyangensis, which clustered with R. fournieri and R. vini in phylogenetic analyses. Field investigations suggest Haemaphysalis longicornis ticks might be involved in transmission.

Rickettsia japonica Infections in Humans, Xinyang, China, 2014-2017.

During 2014-2017, we screened for Rickettsia japonica infection in Xinyang, China, and identified 20 cases. The major clinical manifestations of monoinfection were fever, asthenia, myalgia, rash, and anorexia; laboratory findings included thrombocytopenia and elevated hepatic aminotransferase concentrations. Physicians in China should consider R. japonica infection in at-risk patients.

"HOT" Alkaline Hydrolysis of Amorphous MOF Microspheres to Produce Ultrastable Bimetal Hydroxide Electrode with Boosted Cycling Stability.

Nickel/cobalt hydroxide is a promising battery-type electrode material for supercapacitors. However, its low cycle stability hinders further applications. Herein, Ni0.7 Co0.3 (OH)2 core-shell microspheres exhibiting extreme-prolonged cycling life are successfully synthesized, employing Ni-Co-metal-organic framework (MOF) as the precursor/template and a specific hydrolysis strategy. The Ni-Co-MOF and KOH aqueous solution are separated and heated to 120 °C before mixing, rather than mixing before heating. Through this hydrolysis strategy, no MOF residual exists in the product, contributing to close stacking of the hydroxide nanoflakes to generate Ni0.7 Co0.3 (OH)2 microspheres with a robust core-shell structure. The electrode material exhibits high specific capacity (945 C g-1 at 0.5 A g-1 ) and unprecedented cycling performance (100% after 10 000 cycles). The fabricated asymmetric supercapacitor delivers an energy density of 40.14 Wh kg-1 at a power density of 400.56 W kg-1 and excellent cycling stability (100% after 20 000 cycles). As far as is known, it is the best cycling performance for pure Ni/Co(OH)2 .

MicroRNA-1225-5p acts as a tumor-suppressor in laryngeal cancer via targeting CDC14B.

This study aimed to investigate the role of miRNA-1225-5p (miR-1225) in laryngeal carcinoma (LC). We found that the expression of miR-1225 was suppressed in human LC samples, while CDC14B (cell division cycle 14B) expression was reinforced in comparison with surrounding normal tissues. We also demonstrated that enhanced expression of miR-1225 impaired the proliferation and survival of LC cells, and resulted in G1/S cell cycle arrest. In contrast, reduced expression of miR-1225 promoted cell survival. Moreover, miR-1225 resulted in G1/S cell cycle arrest and enhanced cell death. Further, miR-1225 targets CDC14B 3'-UTR and recovery of CDC14B expression counteracted the suppressive influence of miR-1225 on LC cells. Thus, these findings offer insight into the biological and molecular mechanisms behind the development of LC.

Monolithic radio frequency SiN x self-rolled-up nanomembrane interdigital capacitor modeling and fabrication.

Monolithic capacitors operating at radio frequencies (RF) serve as critical components in integrated circuits for wireless communication. Design and fabrication innovations for high capacitance density RF capacitors are highly desired for the miniaturization of RFIC chips. However, practical and simple solutions are limited by existing capabilities in three-dimensional (3D) structure construction and the effective configuration of electrodes. We report a unique route to achieve unprecedentedly high capacitance density at a high operating frequency through a capacitor configuration of 3D coil interdigital electrodes using planar semiconductor processing compatible materials and fabrication methods. A systematic mechanical-electrical design principle is demonstrated, and fabricated devices show a maximum 21.5 pF capacitance, which is 17.2× larger after rolling up. The corresponding capacitance density is as large as 371 pF mm-2, with resonant frequency of 1.5 GHz. The performance could be improved significantly by simply rolling up more turns with minimal change to the area footprint.

Isolation and Identification of Rickettsia raoultii in Human Cases: A Surveillance Study in 3 Medical Centers in China.

Background: Rickettsia raoultii is frequently detected in multiple tick species, whereas human infection remains scarcely studied. Methods: A surveillance study was performed at 3 sentinel hospitals in China, to recruit participants with suspected tick exposure. Rickettsia raoultii infection was identified through polymerase chain reaction, followed by sequencing, and confirmed serologically. Isolation by cell culture was performed and the isolates were genome sequenced. Results: Twenty-six subjects were determined to have R. raoultii infection, including 7 with asymptomatic infection, 15 with mild to moderate illness, and 4 with severe illness. Common nonspecific manifestations in the 19 patients with mild to moderate or severe illness included fever (100%), malaise (95%), myalgia (58%), lymphadenopathy (53%), and nausea (42%). Only 5% of them had rash, and 16% had eschar. Scalp eschar and neck lymphadenopathy after a tick bite syndrome was only seen in 2 patients. Of the 4 patients with severe complications, 3 developed pulmonary edema, and 1 developed clouding of consciousness and lethargy. Frequent abnormalities of laboratory testing included leukopenia, thrombocytopenia, lymphopenia, neutropenia, hypoproteinemia, and elevated levels of total bilirubin, hepatic aminotransferases, lactate dehydrogenase, and creatine kinase. All the 19 patients recovered without sequelae after receiving doxycycline treatment. Two R. raoultii strains were isolated, and a significantly less degraded genome was observed than other more virulent Rickettsia strains, indicating a low pathogenicity of the current strain. Conclusions: Human infection with R. raoultii has a wide clinical spectrum that ranged from subclinical infection to severe complications. Physicians need to be aware of the high potential and clinical complexity of R. raoultii infection, to ensure appropriate testing and treatment in endemic regions.

Transmission of Severe Fever with Thrombocytopenia Syndrome Virus by Haemaphysalis longicornis Ticks, China.

We demonstrate maintenance and transmission of severe fever with thrombocytopenia syndrome virus by Haemaphysalis longicornis ticks in the larva, nymph, and adult stages with dissemination in salivary gland, midgut, and ovarian tissues. The H. longicornis tick is a competent vector to transmit this virus in both transovarial and transstadial modes.

In Situ CVD Derived Co-N-C Composite as Highly Efficient Cathode for Flexible Li-O2 Batteries.

To promote the development of high energy Li-O2 batteries, it is important to design and construct a suitable and effective oxygen-breathing cathode. Herein, activated cobalt-nitrogen-doped carbon nanotube/carbon nanofiber composites (Co-N-CNT/CNF) as the effective cathodes for Li-O2 batteries are prepared by in situ chemical vapor deposition (CVD). The unique architecture of these electrodes facilitates the rapid oxygen diffusion and electrolyte penetration. Meanwhile, the nitrogen-doped carbon nanotube/carbon nanofiber (N-CNT/CNF) and Co/CoNx serve as reaction sites to promote the formation/decomposition of discharge product. Li-O2 batteries with Co-N-CNT/CNF cathodes exhibit superior electrochemical performance in terms of a positive discharge plateau (2.81 V) and a low charge overpotential (0.61 V). Besides, Li-O2 batteries also present a high discharge capacity (11512.4 mAh g-1 at 100 mA g-1 ), and a long cycle life (130 cycles). Meanwhile, the Co-N-CNT/CNF cathode also has an excellent flexibility, thus the assembled flexible battery with Co-N-CNT/CNF can work normally and hold a wonderful capacity rate under various bending conditions.

Pharmacological analysis of dexmedetomidine hydrochloride in pediatric anesthesia during magnetic resonance imaging.

Dexmendetomidine hydrochloride (DEX) is a new common adrenergic receptor agonist, which not only keeps children calm but also has analgesic effect. Dexmedetomidine hydrochloride will enable children to maintain the natural non-REM sleep, which can be stimulated sedation or language arousal. The aim of this study is to observe the sedative effect and adverse drug reactions of dexmedetomidine hydrochloride injection and propofol injection in MRI examination. In this study, no children in the experimental group were required to add sedative drugs, and 2 cases in the control group were treated with sedative drugs. In experimental group, it used dexmedetomidine hydrochloride as (1.64±0.91) g/kg; in control group, dosage of narcotic drugs as (5.26±1.82) g/kg, and the total complication rate of the children in the experimental group was lower than that of the control group (P<0.05). After returning to the ward, the doses of phenobarbital sedation were dexmedetomidine group (4.28±1.53) mg/kg and propofol group (6.40±1.71) mg/kg. There was significant difference between the two groups. The total complication rate in the experimental group was lower than that in the control group (P<0.05). The quality of MRI in the test group was significantly higher than that in the control group, which showed that dexmedetomidine hydrochloride could provide a satisfactory sedative effect in the MRI examination of children. To sum up, dexmedetomidine hydrochloride is a wide range of clinical applications. It is an effective drug for the maintenance of sedation in clinical disease treatment. It is flexible in the way of administration and with less adverse reactions. It is suitable for popularization and application in clinical practice.

Development and validation of a real-time reverse transcriptase PCR assay for sensitive detection of SFTSV.

BACKGROUND: Severe fever with thrombocytopenia syndrome bunyavirus (sftsv) is an emerging tick-borne rna virus recently identified as the pathogen that causes severe fever with thrombocytopenia syndrome (sfts) in china. the existing commercial nucleic acid testing (comnat) assay with a relatively high claimed limit of quantitative detection (loqd) is not capable of sensitive detection and quantitation of sftsv. Thus, a new real-time reverse transcriptase (rt)-pcr assay with improved sensitivity is needed for clinical diagnosis; it could also be used to screen blood donors if necessary. MATERIALS AND METHODS: We developed a new sftsv rt-pcr nat assay (newnat). About 129 plasma samples from 93 suspected sfts patients with typical clinical symptoms were tested using an anti-sftsv total antibody elisa and both comnat and newnat. The test performance of the two nat assays was evaluated and compared. RESULTS: The newnat had a lower limit for quantitative testing compared to comnat. Twelve samples were comnat negative but newnat positive. Out of 35 suspected sfts patients who were comnat negative and anti-sftsv total antibody negative, four tested positive by the newnat assay and one of these four seroconverted within 2-4 days after testing newnat positive. A high correlation was observed between the cts of the newnat and comnat assays. CONCLUSION: The newnat assay was sensitive for quantitative detection of sftsv and may be applicable to clinical diagnosis and studies of the need for blood donor screening.

Candidatus Rickettsia tarasevichiae Infection in Eastern Central China: A Case Series.

BACKGROUND: Human infection with Candidatus Rickettsia tarasevichiae (CRT) was first reported in northeastern China in 2012. OBJECTIVE: To describe the clinical spectrum and laboratory findings of patients infected with CRT in eastern central China. DESIGN: Case series. SETTING: A sentinel hospital for severe fever with thrombocytopenia syndrome (SFTS) in eastern central China in 2014. PARTICIPANTS: Hospitalized patients with SFTS-like illness. MEASUREMENTS: Molecular and serologic tests were performed to diagnose CRT infection. Data about clinical manifestations and laboratory findings were retrieved from medical records. RESULTS: 56 of 733 assessed patients had CRT based on polymerase chain reaction and sequencing. All patients presented with nonspecific manifestations, including fever (96%), malaise (88%), myalgia (57%), cough (25%), and dizziness (14%). Only 2 patients had rash. Further, 16% had eschar, 29% had lymphadenopathy, 100% had gastrointestinal symptoms, 34% had neurologic symptoms, 43% had hemorrhagic manifestations, and 23% had signs of plasma leakage. Thrombocytopenia was observed in 70%, leukopenia in 59%; lymphopenia in 45%; and elevated levels of lactate dehydrogenase in 82%, aspartate aminotransferase in 70%, alanine aminotransferase in 54%, and creatinine kinase in 46%. Co-infection with SFTS virus was documented in 66% patients, and 8 of the 56 patients died. LIMITATIONS: Patients with CRT were not treated for infection because they were retrospectively identified. This was not a population-based study, and the results cannot be generalized to all patients with CRT. CONCLUSION: Candidatus R tarasevichiae infection should be considered in the differential diagnosis of febrile patients with SFTS-like illness in endemic areas. PRIMARY FUNDING SOURCE: National Natural Science Foundation of China.