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Plant-soil interactions have bottom-up and top-down effects within a plant community. Heavy metal pollution can change plant-soil interactions, directly influence bottom-up effects and indirectly affect herbivores within the community. In turn, herbivores can affect plant-soil interactions through top-down effects. However, the combined effects of heavy metals and herbivores on soil enzymes, plants and herbivores have rarely been reported. Therefore, the effects of lead (Pb), Spodoptera litura and their combined effects on soil enzyme activities, pakchoi nutrition, defence compounds and S. litura fitness were examined here. Results showed that Pb, S. litura and their combined effects significantly affected soil enzymes, pakchoi and S. litura. Specifically, exposure to double stress (Pb and S. litura) decreased soil urease, phosphatase and sucrase activities compared with controls. Furthermore, the soluble protein and sugar contents of pakchoi decreased, and the trypsin inhibitor content and antioxidant enzyme activity increased. Finally, the S. litura development period was extended, and survival, emergence rates and body weight decreased after exposure to double stress. The combined stress of Pb and S. litura significantly decreased soil enzyme activities. Heavy metal accumulation in plants may create a superposition or synergistic effect with heavy metal-mediated plant chemical defence, further suppressing herbivore development. Pb, S. litura and their combined effects inhibited soil enzyme activities, improved pakchoi resistance and reduced S. litura development. The results reveal details of soil-plant-herbivore interactions and provide a reference for crop pest control management in the presence of heavy metal pollution.
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Chumbo , Solo , Spodoptera , Animais , Spodoptera/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento , Spodoptera/enzimologia , Chumbo/toxicidade , Solo/química , Herbivoria , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/enzimologiaRESUMO
Oxidative stress (OS) is a key factor in the generation of various pathophysiological conditions. Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is a major transcriptional regulator of antioxidant reactions. Heme oxygenase-1 (HO-1), a gene regulated by Nrf2, is one of the most critical cytoprotective molecules. In recent years, Nrf2/HO-1 has received widespread attention as a major regulatory pathway for intracellular defense against oxidative stress. It is considered as a potential target for the treatment of inflammatory bowel disease (IBD). This review highlights the mechanism of action and therapeutic significance of Nrf2/HO-1 in IBD and IBD complications (intestinal fibrosis and colorectal cancer (CRC)), as well as the potential of phytochemicals targeting Nrf2/HO-1 in the treatment of IBD. The results suggest that the therapeutic effects of Nrf2/HO-1 on IBD mainly involve the following aspects: (1) Controlling of oxidative stress to reduce intestinal inflammation and injury; (2) Regulation of intestinal flora to repair the intestinal mucosal barrier; and (3) Prevention of ferroptosis in intestinal epithelial cells. However, due to the complex role of Nrf2/HO-1, a more nuanced understanding of the exact mechanisms involved in Nrf2/HO-1 is the way forward for the treatment of IBD in the future.
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BACKGROUND: Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. Ginsenoside may be an ideal agent for UC treatment. However, its efficacy and safety are unknown. We aim to conduct a systematic evaluation to assess the effects and potential mechanisms of ginsenosides in animal models of UC. METHODS: Six electronic databases will be searched (PubMed, Embase, Web of Science, China Knowledge Network (CNKI), China Science and Technology Journal Database (CQVIP), and Wanfang Data Knowledge). SYRCLE list will be used to assess the quality of literature, and STATA 15.1 for data analysis. Time-dose effects analysis will be used to reveal the time-dosage response relations between ginsenosides and UC. RESULTS: Ultimately, fifteen studies involving 300 animals were included. Preliminary evidence was shown that ginsenosides could reduce Disease Activity Index (DAI) scores, weight loss, histological colitis score (HCS), spleen weight, Malondialdehyde (MDA), Myeloperoxidase (MPO) activity, interleukin-1ß (IL-1ß), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and increase colon length (CL), myeloperoxidase (GSH), interleukin 4 (IL-4), interleukin 10 (IL-10), Zonula Occludens-1 (ZO-1) and occludin. Results of time-dose interval analysis indicated that ginsenosides at a dosage of 5-200 mg/kg with an intervention time of 7-28 days were relatively effective. CONCLUSIONS: Preclinical evidence suggests that ginsenoside is a novel treatment for UC. And the mechanisms of ginsenosides in treating UC may involve anti-inflammatory, antioxidant, barrier protection, intestinal flora regulation, and immune regulation. Although, due to the high heterogeneity, further large-scale and high-quality preclinical studies are needed to examine the protection of ginsenosides against UC.
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Colite Ulcerativa , Ginsenosídeos , Colite Ulcerativa/tratamento farmacológico , Ginsenosídeos/farmacologia , Animais , Humanos , Substâncias Protetoras/farmacologia , Modelos Animais de DoençasRESUMO
Photons with high generation rate is one of the essential resources for quantum communication, quantum computing and quantum metrology. Due to the naturally memory-built-in feature, the memory-based photon source is a promising route towards large-scale quantum information processing. However, such photon sources are mostly implemented in extremely low-temperature ensembles or isolated systems, limiting its physical scalability. Here we realize a single-photon source based on a far off-resonance Duan-Lukin-Cirac-Zoller quantum memory at broadband and room-temperature regime. By harnessing high-speed feedback control and repeat-until-success write process, the photon generation rate obtains considerable enhancement up to tenfold. Such a memory-enhanced single-photon source, based on the broadband room-temperature quantum memory, suggests a promising way for establishing large-scale quantum memory-enabled network at ambient condition.
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BACKGROUND: Anemia is a common disorder among pregnant women; however, the effect of anemia on hemoglobin A1c (HbA1c) levels has not been adequately explored. We aim to examine the influence of anemia on the HbA1c concentration and investigate the relationship between erythrocyte indices and HbA1c levels during pregnancy. METHODS: We performed a retrospective analysis of 1369 pregnant Chinese women. The clinical and analytical data were collected. Independent t-test and Analysis of Variance were used for comparative studies, and multiple linear regression analysis was used to identify the association between erythrocyte indices and HbA1c. RESULTS: The differences in HbA1c between non-anemia and mild anemia were negligible, and the differences in HbA1c between non-anemia and moderate anemia were well within the allowable variability for clinical practice (≥0.5% absolute changes). Mean corpuscular hemoglobin (MCH) correlated with HbA1c significantly, independent of pregnancy, trimester, and anemia. The distinction of HbA1c levels between grades of Hb became no significant (P = 0.955), while differences between trimesters persisted after adjusting for MCH. CONCLUSION: Mild and moderate anemia should not be the primary concern when using HbA1c to monitor blood glucose in pregnancy. MCH showed negative correlations with HbA1c independently, suggesting a previously unknown mechanism affecting HbA1c levels.
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Anemia , Índices de Eritrócitos , Anemia/diagnóstico , Feminino , Hemoglobinas Glicadas/análise , Humanos , Gravidez , Gestantes , Estudos RetrospectivosRESUMO
The current strategy to detect acute injury of kidney tubular cells relies on changes in serum levels of creatinine. Yet serum creatinine (sCr) is a marker of both functional and pathological processes and does not adequately assay tubular injury. In addition, sCr may require days to reach diagnostic thresholds, yet tubular cells respond with programs of damage and repair within minutes or hours. To detect acute responses to clinically relevant stimuli, we created mice expressing Rosa26-floxed-stop uracil phosphoribosyltransferase (Uprt) and inoculated 4-thiouracil (4-TU) to tag nascent RNA at selected time points. Cre-driven 4-TU-tagged RNA was isolated from intact kidneys and demonstrated that volume depletion and ischemia induced different genetic programs in collecting ducts and intercalated cells. Even lineage-related cell types expressed different genes in response to the 2 stressors. TU tagging also demonstrated the transient nature of the responses. Because we placed Uprt in the ubiquitously active Rosa26 locus, nascent RNAs from many cell types can be tagged in vivo and their roles interrogated under various conditions. In short, 4-TU labeling identifies stimulus-specific, cell-specific, and time-dependent acute responses that are otherwise difficult to detect with other technologies and are entirely obscured when sCr is the sole metric of kidney damage.
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Injúria Renal Aguda , RNA , Animais , Perfilação da Expressão Gênica , Camundongos , RNA/metabolismoRESUMO
A new species of Goodyera (Orchidaceae) from Tibet, China, G.medogensis, is described and illustrated here. Molecular phylogenetic results based on one nuclear (ITS) and two plastid markers (matK and trnL-F) support the recognition of G.medogensis as a new species in GoodyerasubsectionReticulum. Morphologically, the novelty is most similar to G.biflora, G.vittata and especially to G.hemsleyana, but differs by the thick grid lines of the reticulations with a diffused margin on the adaxial surface of the leaf blades, the inflorescence with more flowers, the obliquely obovate-rhombic petals, the yellow or yellowish labellum without a lamella on the blade, and the shorter trichomes on the floral bracts, sepals and ovary. Finally, a key to the species of Goodyerasubsect.Reticulum in China is also provided.
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Sterol regulatory element-binding protein 1 (SREBP-1), a master transcription factor in lipogenesis and lipid metabolism, is critical for disease progression and associated with poor outcomes in prostate cancer (PCa) patients. However, the mechanism of SREBP-1 regulation in PCa remains elusive. Here, we report that SREBP-1 is transcriptionally regulated by microRNA-21 (miR-21) in vitro in cultured cells and in vivo in mouse models. We observed aberrant upregulation of SREBP-1, fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC) in Pten/Trp53 double-null mouse embryonic fibroblasts (MEFs) and Pten/Trp53 double-null mutant mice. Strikingly, miR-21 loss significantly reduced cell proliferation and suppressed the prostate tumorigenesis of Pten/Trp53 mutant mice. Mechanistically, miR-21 inactivation decreased the levels of SREBP-1, FASN, and ACC in human PCa cells through downregulation of insulin receptor substrate 1 (IRS1)-mediated transcription and induction of cellular senescence. Conversely, miR-21 overexpression increased cell proliferation and migration; as well as the levels of IRS1, SREBP-1, FASN, and ACC in human PCa cells. Our findings reveal that miR-21 promotes PCa progression by activating the IRS1/SREBP-1 axis, and targeting miR-21/SREBP-1 signaling pathway can be a novel strategy for controlling PCa malignancy.
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Proteínas Substratos do Receptor de Insulina/genética , MicroRNAs/genética , Neoplasias da Próstata/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Acetil-CoA Carboxilase/genética , Animais , Proliferação de Células/genética , Progressão da Doença , Ácido Graxo Sintase Tipo I/genética , Regulação Neoplásica da Expressão Gênica/genética , Xenoenxertos , Humanos , Masculino , Camundongos , Neoplasias da Próstata/patologia , Transdução de SinaisRESUMO
To better control the quality of synthetic vanillin obtained by using the guaiacol synthesis method, the olfactory impacts of byproducts on the aroma of the synthetic vanillin samples were evaluated and their optimum concentration ranges were determined. Four byproducts (guaiacol, ortho-vanillin, 5-methyl-vanillin, and 5-formyl-vanillin) were identified by gas chromatography-mass spectrometry (GC-MS) and quantified by gas chromatography-flame ionization detection (GC-FID) in the synthetic vanillin samples with different degrees of purity. The aroma intensities (AIs) of the four byproducts obtained by gas chromatography-olfactometry (GC-O) were: guaiacol (AI: 3.5-4.0, smoke), ortho-vanillin (AI: 1.6-2.5, almond), 5-methyl-vanillin (AI: 2.5-3.3, aldehyde), and 5-formyl-vanillin (AI: 3.2-3.8, green). The aroma perceptual interactions of the four byproducts and the vanillin in the synthetic vanillin samples were determined by S-curve analysis. Guaiacol and 5-methyl-vanillin showed synergistic effects by Feller's additive model. Combined with the results of an addition experiment, when the contents of guaiacol, ortho-vanillin, 5-methyl-vanillin, and 5-formyl-vanillin were within 50, 10, 400, and 1,000 mg/kg respectively, the byproducts had no effects on the aroma quality of the synthetic vanillin samples. PRACTICAL APPLICATION: Synthetic vanillin is one of the most commonly used food additives. Currently, the purity of synthetic vanillin can reach 99.9%, but trace byproducts are still present. Continuing to improve the purity of synthetic vanillin will significantly increase its production costs. Therefore, it is necessary to determine whether the presence of these byproducts affects the aroma quality of the synthetic vanillin samples or not. If they have a negative effect on its aroma, it will be important to reduce their content. If they have no influence or positive role, there is no need to control the content of these byproducts to very low levels. This study determined the content of the byproducts produced during the synthesis of vanillin by guaiacol glyoxylic acid method, judged the perceptual interaction between the byproducts and the vanillin in the synthetic vanillin samples, and determined the optimum range within which the byproducts had no effects on the aroma quality. This study provides a theoretical basis for improving the aroma quality of synthetic vanillin while controlling the production costs.
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Guaiacol , Compostos Orgânicos Voláteis , Benzaldeídos , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Olfatometria , Compostos Orgânicos Voláteis/análiseRESUMO
The inevitable noise and decoherence in the quantum circuit hinder its scalable development, so quantum error correction and quantumness protection for multiple controllable qubits system are necessary. The flatband in the dispersion relation, based on its inherent locality and high degenerate energy band structure, shows non-diffractive transport properties in the line spectrum and has the potential possibility to protect quantum resources in special lattices. The pioneer work has proved that the topologically boundary state is robust to protect the quantumness from disorder and perturbation, which inspires that quantumness can be protected anywhere in a periodic structure, including the boundary state and bulk state. Here, we show the topological protection of quantum resources with different state combinations in a sawtooth lattice. Photons can be localized at any degenerate eigenmode, and the localized effect is determined by only one parameter, without additional modulations. We show a high violation of Cauchy-Schwarz inequality up to 35 standard deviations by measuring cross correlation and auto-correlation of correlated photons. We verify that the topological protection is robust to different wavelengths of correlated photons. Our results suggest an alternative way of exploring topological protection in flatband and bulk state, demonstrating the powerful ability of topological photonics to protect quantum resources.
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Though it is still a big challenge to unify general relativity and quantum mechanics in modern physics, the theory of quantum field related with the gravitational effect has been well developed and some striking phenomena are predicted, such as Hawking radiation. However, the direct measurement of these quantum effects under general relativity is far beyond present experiment techniques. Fortunately, the emulation of general relativity phenomena in the laboratory has become accessible in recent years. However, up to now, these simulations are limited either in classical regime or in flat space whereas quantum simulation related with general relativity is rarely involved. Here we propose and experimentally demonstrate a quantum evolution of fermions in close proximity to an artificial black hole on a photonic chip. We successfully observe the acceleration behavior, quantum creation, and evolution of a fermion pair near the event horizon: a single-photon wave packet with positive energy escapes from the black hole while negative energy is captured. Our extensible platform not only provides a route to access quantum effects related with general relativity, but also has the potentiality to investigate quantum gravity in future.
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The effects of the natural ingredients Angelica sinensis (AS) and Codonopsis pilosula (CP) on the shelf life of chicken seasoning were investigated. Color differences and sensory evaluation were used to indicate sensory differences. Changes in volatiles were monitored. The rate of increase in the color value a* of the AS and CP samples was lower than that in the control. Rancid flavor appeared later in the AS and CP samples than in the control. The levels of aldehydes, ketones, and alkenes increased during storage. A kinetic model was built based on the proportion of aldehydes (main marker), to predict shelf life. The predicted shelf life at room temperature was 60â¯days for the control, 114â¯days for AS, and 89â¯days for CP. The shelf life of chicken seasoning could be prolonged with AS and CP. This kinetic model can be used to predict the shelf life of chicken seasoning.
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Aromatizantes/química , Aldeídos/química , Aldeídos/metabolismo , Alcenos/química , Alcenos/metabolismo , Angelica sinensis/química , Angelica sinensis/metabolismo , Animais , Galinhas , Codonopsis/química , Codonopsis/metabolismo , Cor , Aromatizantes/metabolismo , Armazenamento de Alimentos , Cetonas/química , Cetonas/metabolismo , Cinética , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismoRESUMO
Goodyerinae are one of the most species-rich and widespread subtribes of Orchidaceae but notorious for their taxonomic difficulty. Here, a comprehensive molecular phylogenetic study of the subtribe is presented based on two nuclear (ITS, Xdh) and five plastid (matK, psaB, rbcL, trnL, trnL-F) regions. A total of 119 species were included representing all clades recovered by previous phylogenetic analyses as well as seven outgroups. Maximum parsimony, maximum likelihood and Bayesian inference methods were used to infer the phylogenetic relationships. The results show that the Goodyerinae subdivided into three major subdivisions and six groupings: Pachyplectron, Goodyera clade (including Goodyera procera, Microchilus subclade and Goodyera subclade) and Cheirostylis clade (including Gonatostylis, Cheirostylis subclade and Ludisia subclade). Four genera, Erythrodes, Goodyera, Myrmechis and Odontochilus, are not monophyletic. The results support Odontochilus s. l. to include Myrmechis and Kuhlhasseltia. The systematic positions of Goodyera procera and two isolated genera, Herpysma and Orchipedum, are difficult to determine.
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Orchidaceae/classificação , Teorema de Bayes , Núcleo Celular/genética , Orchidaceae/genética , Filogenia , Plastídeos/genéticaRESUMO
Background: Because the pathogenesis of high altitude polycythemia (HAPC) is unclear, the aim of the present study was to explore whether abnormal iron metabolism is involved in the pathogenesis of HAPC and the possible cause. Methods: We examined the serum levels of iron, total iron binding capacity, soluble transferrin receptor (sTfR), ferritin, and hepcidin as well as erythropoietin (EPO) and inflammation-related cytokines in 20 healthy volunteers at sea level, 36 healthy high-altitude migrants, and 33 patients with HAPC. Mice that were exposed to a simulated hypoxic environment at an altitude of 5,000 m for 4 weeks received exogenous iron or intervention on cytokines, and the iron-related and hematological indices of peripheral blood and bone marrow were detected. The in vitro effects of some cytokines on hematopoietic cells were also observed. Results: Iron mobilization and utilization were enhanced in people who had lived at high altitudes for a long time. Notably, both the iron storage in ferritin and the available iron in the blood were elevated in patients with HAPC compared with the healthy high-altitude migrants. The correlation analysis indicated that the decreased hepcidin may have contributed to enhanced iron availability in HAPC, and decreased interleukin (IL)-10 and IL-22 were significantly associated with decreased hepcidin. The results of the animal experiments confirmed that a certain degree of iron redundancy may promote bone marrow erythropoiesis and peripheral red blood cell production in hypoxic mice and that decreased IL-10 and IL-22 stimulated iron mobilization during hypoxia by affecting hepcidin expression. Conclusion: These data demonstrated, for the first time, that an excess of obtainable iron caused by disordered IL-10 and IL-22 was involved in the pathogenesis of some HAPC patients. The potential benefits of iron removal and immunoregulation for the prevention and treatment of HAPC deserve further research.
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BACKGROUND: Chicken seasoning is a widely consumed palatable seasoning made with chicken meat. Quality, and especially sensory quality, may determine the consumer choice of food. The same bag of chicken seasoning will be stored by the consumers over a long period of time when it is in use, so it is particularly important to be able to assess its sensory quality. However, the sensory quality defects of chicken seasoning during storage remain unknown. This study evaluated flavor changes in chicken seasoning during storage using sensory evaluation and gas chromatography-mass spectrometry (GC-MS). RESULTS: The sensory evaluation indicated a perceptible change in rancidity during storage. The GC-MS results showed increases in the content of aldehydes, heterocyclic compounds, ketones, and sulfur compounds associated with lipid oxidation. A random forest model was constructed to predict the storage time based on the data for volatile compounds related to lipid oxidation. The low average predicted error indicated a good correlation between lipid oxidation and storage time. CONCLUSION: These results suggest that lipid oxidation is the main factor behind sensory quality defects in chicken seasoning during storage. This can be used as the basis for further evaluation of sensory quality and the shelf life of chicken seasoning. © 2018 Society of Chemical Industry.
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Condimentos/análise , Aromatizantes/química , Carne/análise , Animais , Galinhas , Armazenamento de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lipídeos/química , Oxirredução , Controle de Qualidade , PaladarRESUMO
Little is known about levels and patterns of genetic diversity for the entire range of endangered orchids native to China, Korea, and Japan. In this study, we focus on Cypripedium japonicum and suggest three hypotheses: 1) that genetic drift has been a primary evolutionary force; 2) that populations in central and western China harbor higher levels of genetic variation relative to those from eastern China; and 3) that C. japonicum in China maintains the highest genetic variation among the three countries. Using ISSR and SCoT markers, we investigated genetic diversity in 17 populations to test the three hypotheses. As anticipated, we found low levels of genetic diversity at the species level with substantially high degree of genetic divergence, which can be mainly attributed to random genetic drift. Chinese populations harbor the highest within-population genetic variation, which tends to increase from east to west. We also found a close relationship between Korean populations and central/western Chinese populations. Historical rarity coupled with limited gene flow seems to be important factors for shaping genetic diversity and structure of C. japonicum. Our results indicate that the mountain areas in central and western China were likely refugia at the Last Glacial Maximum.
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Orchidaceae/genética , China , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Ásia Oriental , Fluxo Gênico , Deriva Genética , Variação Genética/genética , Genética Populacional/métodos , Japão , Filogenia , República da CoreiaRESUMO
To determine whether adult kidney papillary label-retaining cells (pLRCs) are specialized precursors, we analyzed their transcription profile. Among genes overexpressed in pLRCs, we selected candidate genes to perform qPCR and immunodetection of their encoded proteins. We found that Zfyve27, which encodes protrudin, identified a subpopulation of pLRCs. With Zfyve27-CreERT2 transgenic and reporter mice we generated bitransgenic animals and performed cell-lineage analysis. Post tamoxifen, Zfyve27-CreERT2 marked cells preferentially located in the upper part of the papilla. These cells were low cycling and did not generate progeny even after long-term observation, thus they did not appear to contribute to kidney homeostasis. However, after kidney injury, but only if severe, they activated a program of proliferation, migration, and morphogenesis generating multiple and long tubular segments. Remarkably these regenerated tubules were located preferentially in the kidney medulla, indicating that repair of injury in the kidney is regionally specified. These results suggest that different parts of the kidney have different progenitor cell pools.
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Diferenciação Celular/genética , Medula Renal/metabolismo , Rim/metabolismo , Regeneração/genética , Proteínas de Transporte Vesicular/genética , Injúria Renal Aguda/genética , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula/genética , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação da Expressão Gênica no Desenvolvimento , Rim/crescimento & desenvolvimento , Rim/patologia , Medula Renal/crescimento & desenvolvimento , Medula Renal/patologia , Camundongos , Células-Tronco/metabolismo , Tamoxifeno/farmacologia , Proteínas de Transporte Vesicular/metabolismoRESUMO
Infection rates of rodents have a significant influence on the transmission of hemorrhagic fever with renal syndrome (HFRS). In this study, four cities and two counties with high HFRS incidence in eastern Hunan Province in China were studied, and surveillance data of rodents, as well as HFRS cases and related environmental variables from 2007 to 2010, were collected. Results indicate that the distribution and infection rates of rodents are closely associated with environmental conditions. Hantavirus infections in rodents were positively correlated with temperature vegetation dryness index and negatively correlated with elevation. The predictive risk maps based on multivariate regression model revealed that the annual variation of infection risks is small, whereas monthly variation is large and corresponded well to the seasonal variation of human HFRS incidence. The identification of risk factors and risk prediction provides decision support for rodent surveillance and the prevention and control of HFRS.
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Infecções por Hantavirus/epidemiologia , Febre Hemorrágica com Síndrome Renal/epidemiologia , Umidade , Orthohantavírus , Animais , China/epidemiologia , Humanos , Fatores de Risco , Roedores , Estações do Ano , Fatores de TempoRESUMO
BACKGROUND: Increased risks for hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus have been observed since 2005, in Xi'an, China. Despite increased vigilance and preparedness, HFRS outbreaks in 2010, 2011, and 2012 were larger than ever, with a total of 3,938 confirmed HFRS cases and 88 deaths in 2010 and 2011. METHODS AND FINDINGS: Data on HFRS cases and weather were collected monthly from 2005 to 2012, along with active rodent monitoring. Wavelet analyses were performed to assess the temporal relationship between HFRS incidence, rodent density and climatic factors over the study period. Results showed that HFRS cases correlated to rodent density, rainfall, and temperature with 2, 3 and 4-month lags, respectively. Using a Bayesian time-series Poisson adjusted model, we fitted the HFRS outbreaks among humans for risk assessment in Xi'an. The best models included seasonality, autocorrelation, rodent density 2 months previously, and rainfall 2 to 3 months previously. Our models well reflected the epidemic characteristics by one step ahead prediction, out-of-sample. CONCLUSIONS: In addition to a strong seasonal pattern, HFRS incidence was correlated with rodent density and rainfall, indicating that they potentially drive the HFRS outbreaks. Future work should aim to determine the mechanism underlying the seasonal pattern and autocorrelation. However, this model can be useful in risk management to provide early warning of potential outbreaks of this disease.
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Surtos de Doenças/estatística & dados numéricos , Vírus Hantaan , Febre Hemorrágica com Síndrome Renal/epidemiologia , Roedores/fisiologia , Estações do Ano , Animais , Teorema de Bayes , China/epidemiologia , Surtos de Doenças/história , História do Século XXI , Humanos , Incidência , Modelos Teóricos , Distribuição de Poisson , Dinâmica Populacional , TemperaturaRESUMO
Japanese encephalitis (JE) is one of the major vector-borne diseases in Southeast Asia and the Western Pacific region, posing a threat to human health. In rural and suburban areas, traditional rice farming and intensive pig breeding provide an ideal environment for both mosquito development and the transmission of JEV among human beings. Combining surveillance data for mosquito vectors, human JE cases, and environmental conditions in Changsha, China, 2004-2009, generalized threshold models were constructed to project the mosquito and JE dynamics. Temperature and rainfall were found to be closely associated with mosquito density at 1, and 4month lag, respectively. The two thresholds, maximum temperature of 22-23°C for mosquito development and minimum temperature of 25-26°C for JEV transmission, play key roles in the ecology of JEV. The model predicts that, in the upper regime, a 1g/m(3) increase in absolute humidity would on average increase human cases by 68-84%. A shift in mosquito species composition in 2007 was observed, and possibly caused by a drought. Effective predictive models could be used in risk management to provide early warnings for potential JE transmission.