Ginkgolide B improved postoperative cognitive dysfunction by inhibiting microgliosis-mediated neuroinflammation in the hippocampus of mice.

BACKGROUND: Postoperative cognitive dysfunction (POCD) are a common complication of the central nervous system following surgery and anesthesia. The specific pathogenesis and effective therapeutics of POCD need to be further studied. Ginkgolide B (GB), a platelet-activating factor receptor-specific antagonist, has been suggested to have strong anti-inflammatory effects. Here we tested the effects and mechanism of GB on POCD of aged rats. METHODS: Neurobehavioral tests were used to investigate the effect of GB pretreatment on POCD. The hippocampus were harvested to test the expression of proinflammatory cytokines by ELISA. The expression of the microglial marker ionized calcium-binding adaptor molecule-1 (Iba-1) in the hippocampus was evaluated by western blot assay and immunohistochemistry. A Nissl staining experiment was used to detect the neuronal numbers in the hippocampus. RESULTS: Surgery might result in the overexpression of platelet activating factor (PAF) in the plasma and hippocampus and might cause hippocampus-dependent memory impairment. GB pretreatment, inhibited the activation of microglia, reduced the levels of IL-1ß and TNF-α, decreased the loss of neurons after surgery, and prevented POCD in aged rats. CONCLUSION: Our findings suggested that PAF was involved in the development of POCD. Improvement of POCD by PAF antagonist GB was associated with the inhibition of microgliosis-mediated neuroinflammation and neuronal apoptosis in aged rats.

Anaerobic Degradation of Paraffins by Thermophilic Actinobacteria under Methanogenic Conditions.

Microbial anaerobic alkane degradation is a key process in subsurface oil reservoirs and anoxic environments contaminated with petroleum, with a major impact on global carbon cycling. However, the thermophiles capable of water-insoluble paraffins (>C17) degradation under methanogenic conditions has remained understudied. Here, we established thermophilic (55 °C) n-paraffins-degrading (C21-C30) cultures from an oil reservoir. After over 900 days of incubation, the even-numbered n-paraffins were biodegraded to methane. The bacterial communities are dominated by a novel class-level lineage of actinobacteria, 'Candidatus Syntraliphaticia'. These 'Ca. Syntraliphaticia'-like metagenome-assembled genomes (MAGs) encode a complete alkylsuccinate synthases (ASS) gene operon, as well as hydrogenases and formate dehydrogenase, and several enzymes potentially involved in alkyl-CoA oxidation and the Wood-Ljungdahl pathway. Metatranscriptomic analysis suggests that n-paraffins are activated via fumarate addition reaction, and oxidized into carbon dioxide, hydrogen/formate and acetate by 'Ca. Syntraliphaticia', that could be further converted to methane by the abundant hydrogenotrophic and acetoclastic methanogens. We also found a divergent methyl-CoM reductase-like complex (MCR) and a canonical MCR in two MAGs representing 'Ca. Methanosuratus' (within candidate phylum Verstraetearchaeota), indicating the capability of methane and short-chain alkane metabolism in the oil reservoir. Ultimately, this result offers new insights into the degradability and the mechanisms of n-paraffins under methanogenic conditions at high temperatures.

[Analysis of schistosomiasis prevalence in endemic areas using retrospective space-time permutation scan statistics].

Objective: To analyze the characteristics of schistosomasis prevalence by using the spatial epidemiological method, and test the application of retrospective space-time permutation scan statistics in determining mountainous and lake-type endemic areas of schistosomiasis. Methods: The data of schistosomasis in humans, cattle and snails in Jiangxi Province during 2009-2014 and in Yunnan Province during 2004-2013 were collected and analyzed. The temporal and spatial distribution of schistosomiasis endemic areas in the two provinces was analyzed with retrospective space-time permutation scan statistics. Results: The prevalence of schistosomiasis in residents and Oncomelania snails showed a trend of decline in Jiangxi, from 0.21% and 0.03% in 2009 to 0.01% and zero in 2014. A similar trend was found in cattle, from 1.25% in 2012 to 0.12% in 2014. The average annual percentage change (APC) in residents was-47.36%(P < 0.05). The space-time permutation clustering analysis revealed a temporal and spatial clustering of schistosomiasis prevalence from 2009 to 2014 in residents, cattle, and snails, with 3,2 and 1 clustering areas, respectively, all distributed in Poyang Lake Region. A similar declining trend of schistosomiasis prevalence was found in residents, snails and cattle in Yunnan during 2004-2013, from 2.49%,0.70% and 3.76% in 2004 to no infection in residents and snails and 0.02% in cattle in 2013. The APC in residents was-49.17%(P < 0.05). There was a temporal and spatial clustering of schistosomiasis prevalence during 2004-2013 in residents, cattle, and snails, with 2,2 and 6 clustering areas, respectively. Conclusion: A declining trend of schistosomiasis prevalence is shown in lake-type endemic areas in Jiangxi during 2009-2014 and in mountainous endemic areas in Yunnan during 2004-2013. The retrospective space-time permutation scan statistics reveal a clustering of schistosomiasis in humans, cattle, and snails, suggesting its applicability in analyzing the temporal and spatial distribution of schistosomiasis.

Anti-inflammatory polyphenol constituents derived from Cissus pteroclada Hayata.

A new bergenin derivative, bergenin-11-O-α-d-galactopyranoside (compound 1), together with seven known polyphenolic compounds, were isolated from the stem of Cissus pteroclada Hayata. The structures of the 8 compounds were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Moreover, the in vitro anti-inflammatory effects of compounds (1-8) in LPS-stimulated murine macrophage RAW 264.7 cells were also investigated. Our results revealed that compound 1 inhibited the production of pro-inflammatory mediators NO and PGE2 and the expression of NF-κB, TNF-α, IL-1ß, iNOS and COX-2.

[Interpretation of Criteria for Diagnosis of Toxoplasmosis].

The criteria for Diagnosis of Toxoplasmosis (WS/T 486-2015)（referred to as the Criteria） was compiled following the Management Measures for Health Criteria and GBT 1.1-2009 Standardization Working Guidelines. The Criteria is composed of six chapters, including the range of application, terms and definitions, diagnostic principle, diagnostic standard, and differential diagnosis. Four informative appendices (etiology, epidemiology, clinical manifestation, and differential diagnosis) and one normative appendix (laboratory examination) are appended. The Criteria was issued by the National Health and Family Planning Commission of the People's Republic of China through No.21 of Chinese Health Announcement in 2015. The Criteria provides for the first time technical reference for diagnosis of toxoplasmosis in medical institutions and disease control institutions.

[Development and application of information system for epidemiological investigation on parasitic diseases].

An information system for epidemiological investigation on parasitic diseases was developed. The foreground of this system was realized by using C# programming language, and the ACCESS database was used to implement the data management. The system was improved by continuous field application, and has been updated from version 1.0 to 3.0. The average treatment time, logic error rate, rate of sample loss, and post-processing error rate have now been reduced by 88.0%, 100%, 98.1%, and 100%, respectively (P<0.01). This system can reduce the human error and change the field investigation into effective and high-quality pattern.

Assessment of the influence of levees along Yangtze River on Oncomelania hupensis, the intermediate host of Schistosoma japonicum.

BACKGROUND: Oncomelania hupensis is the exclusive intermediate host of Schistosoma japonicum in China. Snail control is an essential component of schistosomiasis elimination programme. With 70 years of continuous efforts, the range of O. hupensis had reduced significantly, but slowed down in last decades. A large number of levees against flooding were constructed along Yangtze River and its affiliated lakes in the middle and lower reaches, which influenced the hydrology and ecology in the alluvial plains. The purpose of this study was to assess the impact of levees on the distribution of O. hupensis in the middle and lower reaches of the Yangtze River. METHODS: The snail habitats were digitalised by hand-held GPS system. The years for discovery and elimination of snail habitats were extracted from historical records. The accumulated snail-infested range for each habitat was calculated on the basis of annual reports. The current distribution of O. hupensis was determined by systematic and environmental sampling. The geographical distribution of levees was obtained from satellite imagery. To assess the impact of levees, the data pertaining to O. hupensis were divided into two parts: inside and outside the Yangtze River. Joinpoint regression was utilised to divide the study time span and further characterise the regression in each period. The 5-year-period moving averages of eliminated area infested by snails were calculated for the habitats inside and outside Yangtze River. The moving routes of corresponding geographical median centres were simulated in ArcGIS. Hotspot analysis was used to determine the areas with statistical significance clustering of O. hupensis density. RESULTS: Three periods were identified according to Joinpoint regression both inside and outside Yangtze River. The area infested by O. hupensis increased in the first two periods. It decreased rapidly outside Yangtze River year over year after 1970, while that inside the Yangtze River did not change significantly. Furthermore, the latter was significantly higher than the former. It was observed that the present density of O. hupensis inside Yangtze River was lower than outside the Yangtze River. The median centre for eliminated ranges inside Yangtze River wavered between the east (lower reach) and the west (middle reach). In contrast, the median centre for eliminated ranges continuously moved from the east to the west. CONCLUSIONS: Our findings indicated that the levees had a considerable negative impact on the distribution of O. hupensis outside Yangtze River. Some hotspots observed in the irrigation areas need a sluice system at the inlet of branch for snail control. The major distribution of O. hupensis located in Hubei might be caused by severe waterlogging. The intensive surveillance should be implemented there. The biggest two freshwater lakes, the major endemic regions historically, were identified as cold spots. The long-term impact of Three Gorges Dam on the distribution of O. hupensis in the lakes should be monitored and evaluated.

Glutenin-chitosan 3D porous scaffolds with tunable stiffness and systematized microstructure for cultured meat model.

A glutenin (G)-chitosan (CS) complex (G-CS) was cross-linked by water annealing with aim to prepare structured 3D porous cultured meat scaffolds (CMS) here. The CMS has pore diameters ranging from 18 to 67 µm and compressive moduli from 16.09 to 60.35 kPa, along with the mixing ratio of G/CS. SEM showed the porous organized structure of CMS. FTIR and CD showed the increscent content of α-helix and ß-sheet of G and strengthened hydrogen-bondings among G-CS molecules, which strengthened the stiffness of G-CS. Raman spectra exhibited an increase of G concentration resulted in higher crosslinking of disulfide-bonds in G-CS, which aggrandized the bridging effect of G-CS and maintained its three-dimensional network. Cell viability assay and immuno-fluorescence staining showed that G-CS effectively facilitated the growth and myogenic differentiation of porcine skeletal muscle satellite cells (PSCs). CLSM displayed that cells first occupied the angular space of hexagon and then ring-growth circle of PSCs were orderly formed on G-CS. The texture and color of CMS which loaded proliferated PSCs were fresh-meat like. These results showed that physical cross-linked G-CS scaffolds are the biocompatible and stable adaptable extracellular matrix with appropriate architectural cues and natural micro-environment for structured CM models.

[Prevalence and control of schistosomiasis in Jiangxi Province during 2002-2012].

OBJECTIVE: To analyze the status of prevalence and control of schistosomiasis in Jiangxi Province from 2002 to 2012. METHODS: Endemic status and control effectiveness during the period from 2002 to 2012 was analyzed by using a combination of field survey, data collection and retrospective investigation. RESULTS: From 2002 to 2012, schistosomiasis control made significant achievements in Jiangxi Province. The number of counties which have reached the criteria of transmission interruption of schistosomiasis increased from 19 in 2002 to 22 in 2012. The number of patients with schistosome infection decreased from 128 331 in 2002 to 73 102 in 2012. The positive rate of serological test and fecal examination in residents decreased from 12.2% and 4.2% in 2002 to 5.2% and 0.4% in 2012, respectively. Acute infection reduced from 146 cases in 2002 to 3 cases in 2012, but advanced cases increased by 42.4%. The positive rate of fecal examination in cattle reduced from 4.7% in 2002 to 1.3% in 2012. The density of living snails and infected snails significantly decreased to 0.083 5/0.1 a? and 0.000 037/0.1 m2 in 2012, respectively. However, the snail-ridden areas slightly increased. Jiangxi Province reached the criteria of endemic control for schistosomiasis in 2008. During 2002-2012, control activities were intensified. Examination and chemotherapy for human increased by 65.2% and 65.5%, while 23.4% and 251.1% for cattle. Mean while, area with snail control activities increased by 617.8%. An integrated strategy of infection source control was implemented in the Province. CONCLUSION: During 2002 to 2012, endemic index of schistosomiasis in Jiangxi showed a steady decline after 2005. Currently, schistosomiasis prevalence shows a low level. The endemic indicators of infection in human and livestock as well as Oncomelania snails have been kept stable at low level.

[Effect of MXRA7 on the Biological Functions of Acute B Lymphoblastic Leukemia Cell Line REH].

OBJECTIVE: To discover the relationship between matrix remodeling associated 7 (MXRA7) and acute B lymphoblastic leukemia (B-ALL), and explore the effect of MXRA7 on the biological functions of B-ALL cell line REH. METHODS: The expression of MXRA7 in blood diseases was searched and analyzed through BloodSpot database. Real-time qPCR was used to detect the expression level of MXRA7 in B-ALL cell line 697 and REH cells. Lentivirus-mediated shRNA interference technology was utilized to knock down the expression of MXRA7 in REH cells. The effects of MXRA7 on the biological functions of REH cells were studied by in vitro experiments. Cell proliferation was detected by CCK-8 assay, cell cycle was detected by PI staining, cell apoptosis was detected by Annexin V and 7-AAD staining, and the expression of apoptosis pathway related proteins was detected by Western blot. RESULTS: Database analysis showed that MXRA7 was highly expressed in B-ALL patients, and real-time qPCR results showed that MXRA7 was also highly expressed in cell lines 697 and REH cells. Knockdown of MXRA7 in REH cells inhibited the cell proliferation and increased the percentage of G0/G1 phase cells. After treatment with cytarabine, the apoptotic ratio was increased in MXRA7-impaired REH cells, and the activation of caspase-3 and caspase-9 were also increased. CONCLUSION: Knockdown of MXRA7 can reduce the malignancy of REH cells by inhibiting the cell proliferation and increasing the sensitivity of REH cells to cytarabine. These results indicate MXRA7 may be as a novel target for the treatment of B-ALL, and the potential usefulness of MXRA7 in B-ALL deserves further investigation.

The Impact of Flooding on Snail Spread: The Case of Endemic Schistosomiasis Areas in Jiangxi Province, China.

Flooding is the main natural factor in snail diffusion, and it has a negative impact on schistosomiasis transmission. There are few studies on the spread and migration of snails following a flood; therefore, we aimed to investigate the influence of flooding on snail diffusion and explore the characteristics and laws of snail diffusion in Jiangxi Province. By using a retrospective survey and cross-sectional survey, the data on snail spreading in Jiangxi Province from 2017 to 2021 were collected. The distribution, nature, and area of snail spread were systematically analyzed in combination with the hydrological situation, types of region, and types of flood. From 2017 to 2021, a total of 120 snail-spread environments were found, including in 92 hilly areas and in 28 lake areas. The areas caused by flood and by other means numbered 6 and 114, respectively. The proportions of recurrence, expansion, and first-time occurrences were 43.42%, 38.16%, and 18.42%, respectively, and the 14 new snail environments were only distributed in the hilly areas. With the exception of 2018, the ratio of snail-spread areas in the hilly region was higher than that in lake region in other years. The average density of live snails was 0.0184-1.6617 no./0.1 m2 and 0.0028-0.2182 no./0.1 m2 in the hilly region. Among the 114 environments affected by floods, 86 consisted of hilly environments, including 66 spreading environments affected by rainstorm floods, and 20 rainstorm debris flow environments. There were 28 lake areas, of which 10 were in the Jiangxi section of Yangtze River and were affected by rainstorm floods. Snail spread following flooding has a certain 'lag effect,' and = simple annual changes in hydrological characteristics have little effect on the diffusion of snails or on their density = in the affected environment, but it is more closely related to local floods. The hilly environments are more susceptible to floods than the lake region, and the risk of snail spread is much higher in the hilly than in the lake region.

[Field application of antibody detection in a low transmission area of Schistosoma japonicum].

OBJECTIVE: To evaluate the field application of IHA and ELISA for schistosomiasis japonica detection at low transmission status. METHODS: 728 and 799 persons were examined by Kato-Katz's method, IHA and ELISA for schistosomiasis in an endemic village in the year of 2008 and 2010, respectively. The results of IHA and ELISA was evaluated in comparison to that of Kato-Katz (27 slides with 3 stool specimens) used as gold standard. RESULTS: The positive rate of Kato-Katz's method, IHA and ELISA were 10.3% (75/728), 40.0% (291/728) and 40.1% (292/728) in 2008, and 3.8% (30/799), 31.5% (252/799) and 40.1% (320/799) in 2010 respectively, in which significant difference was observed for the result between Kato-katz's method (chi2 = 26.92, P < 0.05) and IHA (chi2 = 11.82, P < 0.05). The consistency between the result of antibody detection and that of Kato-Katz's method was poor, lower than 0.2 (P < 0.01). If routine screening diagnosis mode was adopted, namely, population screened with IHA or ELISA first and confirmed with Kato-Katz's method, correlation analysis showed that the positive rate of Kato-Katz's method increased with the number of stool specimens and slides (rIHA2008 = 0.922, rELISA2008 = 0.908, rIHA2010 = 0.749, rELISA = 0.798; P < 0.05) . Those with egg positive but missed by IHA or ELISA mainly were cases with low infection intensity. When EPG < or = 40, the rate of detection ranged from 66.1% (39/59) to 87.0% (20/23) with IHA, and 62.7% (37/59) to 100% (23/23) with ELISA. When EPG > 40, however, all cases could be detected with ELISA, but some missed with IHA. CONCLUSION: In low transmission areas, the determination of target population for chemotherapy should be based on the examination of nine slides per stool specimen by Kato-Katz's method after serological screening.

[The Effect of Matrix Remodeling Associated 7 (MXRA7) Expression on the Biological Function of SHI-1 Cells].

OBJECTIVE: To express matrix remodeling associated 7 (MXRA7) in the human acute myeloid leukemia SHI-1 cell line and to assess the role of MXRA7 in the biological function of SHI-1 cells. METHODS: The full-length cDNA sequence of human MXRA7 was synthesized and subcloned into the lentivirus shuttle vector pRRL-Venus. SHI-1 cells were transfected with the lentivirus which was packaged with 293T cells. The YFP-positive cells were sorted by flow cytometry and the stable cell lines were obtained by expanded culture. The expression and distribution of MXRA7 in SHI-1 cells were verified by real-time qPCR, Western blot and laser confocal techniques. Cell proliferation and cell cycle were measured by flow cytometry, and apoptosis was determined by Annexin V and 7-AAD staining. The expression of apoptosis related proteins were detected by Western blot. RESULTS: The stable SHI-1 cell line overexpressing MXRA7 was established successfully. Laser confocal analysis confirmed that MXRA7 was expressed in the cytoplasm of SHI-1 cells. Compared with the control cell line, the overexpression of MXRA7 showed no effect on the cell proliferation and cell cycle, but reduced the percentage of apoptosis cells induced by methotrexate. Moreover, the expression of BCL-2 protein was increased by overexpression of MXRA7, which can inhibit cell apoptosis. CONCLUSION: The SHI-1 stable cell line overexpressing MXRA7 was established successfully, and MXRA7 could inhibit drug-induced apoptosis through increasing the expression of BCL-2 protein.

Lipid nanoparticle-encapsulated mRNA antibody provides long-term protection against SARS-CoV-2 in mice and hamsters.

Monoclonal antibodies represent important weapons in our arsenal to against the COVID-19 pandemic. However, this potential is severely limited by the time-consuming process of developing effective antibodies and the relative high cost of manufacturing. Herein, we present a rapid and cost-effective lipid nanoparticle (LNP) encapsulated-mRNA platform for in vivo delivery of SARS-CoV-2 neutralization antibodies. Two mRNAs encoding the light and heavy chains of a potent SARS-CoV-2 neutralizing antibody HB27, which is currently being evaluated in clinical trials, were encapsulated into clinical grade LNP formulations (named as mRNA-HB27-LNP). In vivo characterization demonstrated that intravenous administration of mRNA-HB27-LNP in mice resulted in a longer circulating half-life compared with the original HB27 antibody in protein format. More importantly, a single prophylactic administration of mRNA-HB27-LNP provided protection against SARS-CoV-2 challenge in mice at 1, 7 and even 63 days post administration. In a close contact transmission model, prophylactic administration of mRNA-HB27-LNP prevented SARS-CoV-2 infection between hamsters in a dose-dependent manner. Overall, our results demonstrate a superior long-term protection against SARS-CoV-2 conferred by a single administration of this unique mRNA antibody, highlighting the potential of this universal platform for antibody-based disease prevention and therapy against COVID-19 as well as a variety of other infectious diseases.

KRT18 Modulates Alternative Splicing of Genes Involved in Proliferation and Apoptosis Processes in Both Gastric Cancer Cells and Clinical Samples.

Keratin 18 (KRT18), one of the most abundant keratins in epithelial and endothelial cells, has been reported to be aberrantly expressed in many malignancies and extensively regarded as a biomarker and important regulator in multiple cancers, including gastric cancer (GC). But the molecular regulatory mechanisms of KRT18 in GC patients and cells are largely unknown. In the present study, we analyzed the expression level of KRT18 in 450 stomach adenocarcinoma tissue samples from TCGA database and found a significantly higher expression level in tumor tissues. We then explored the potential functions of KRT18 in AGS cells (human gastric adenocarcinoma cell line) by KRT18 knockdown using siRNA and whole transcriptome RNA-seq analysis. Notably, KRT18 selectively regulates expression of cell proliferation and apoptotic genes. Beyond this, KRT18 affects the alternative splicing of genes enriched in apoptosis, cell cycle, and other cancer-related pathways, which were then validated by reverse transcription-quantitative polymerase chain reaction approach. We validated KRT18-KD promoted apoptosis and inhibited proliferation in AGS cells. We then used RNA-seq data of GC samples to further demonstrate the modulation of KRT18 on alternative splicing regulation. These results together support the conclusion that KRT18 extensively modulates diverse alternative splicing events of genes enriched in proliferation and apoptosis processes. And the dysregulated splicing factors at transcriptional or posttranscriptional level by KRT18 may contribute to the alternative splicing change of many genes, which expands the functional importance of keratins in apoptotic and cell cycle pathways at the posttranscriptional level in GC.

The Dynamics of Hepatic Fibrosis Related to Schistosomiasis and Its Risk Factors in a Cohort of China.

China has had a long history against schistosomiasis japonica. The most serious prognosis of chronic schistosome infection is hepatic fibrosis, which develops into advanced schistosomiasis if the process is not effectively controlled. After a more than seven decades endeavor, China has gained remarkable achievements in schistosomiasis control and achieved transmission control nationwide (infection rate of schistosomes in residents and domestic animals both less than 1%) by 2015. However, new advanced schistosomiasis cases emerge annually in China, even in areas where the transmission of schistosomiasis had been interrupted. In the present study, the residents (>5 years old) in a schistosomiasis endemic village were examined for schistosomiasis every year during 1995-2019 by the modified Kato-Katz thick smear method and/or miracidium hatching technique. Residents who were identified to have an active infection method were treated with praziquantel at a dose of 40 mg/kg body weight. Ultrasonography was carried out to assess the liver morbidity related to schistosomiasis in 1995 and 2019, respectively. The prevalence of schistosomiasis among residents presented a downward trend annually, from 17.89% (175/978) in 1995 to 0 (0/475) in 2019. Among 292 residents who received ultrasound scan both in 1995 and 2019, 141 (48.29%) presented stable liver damage, while liver fibrosis was developed severely in 86 (29.45%) and reversed in 65 (22.26%) residents. Univariate and multivariate analysis showed that anti-fibrosis treatment was the protective factor against schistosomiasis hepatic fibrosis. Males, residents aged 38 and above, fishermen, and people who did not receive anti-fibrosis treatment were groups with higher risk of liver fibrosis development. Our results revealed that although the infection rate of schistosome dropped significantly in endemic areas, liver fibrosis was still developing among some residents, even though they had received deworming treatment. Liver protection/anti-fibrosis treatment should be administered in endemic regions and regions with historically uncontrolled transmission to slow down the deterioration of hepatic fibrosis among patients in schistosomiasis endemic areas.

Potential impact of flooding on schistosomiasis in Poyang Lake regions based on multi-source remote sensing images.

BACKGROUND: Flooding is considered to be one of the most important factors contributing to the rebound of Oncomelania hupensis, a small tropical freshwater snail and the only intermediate host of Schistosoma japonicum, in endemic foci. The aim of this study was to assess the risk of intestinal schistosomiasis transmission impacted by flooding in the region around Poyang Lake using multi-source remote sensing images. METHODS: Normalized Difference Vegetation Index (NDVI) data collected by the Landsat 8 satellite were used as an ecological and geographical suitability indicator of O. hupensis habitats in the Poyang Lake region. The expansion of the water body due to flooding was estimated using dual-polarized threshold calculations based on dual-polarized synthetic aperture radar (SAR). The image data were captured from the Sentinel-1B satellite in May 2020 before the flood and in July 2020 during the flood. A spatial database of the distribution of snail habitats was created using the 2016 snail survey in Jiangxi Province. The potential spread of O. hupensis snails after the flood was predicted by an overlay analysis of the NDVI maps in the flood-affected areas around Poyang Lake. The risk of schistosomiasis transmission was classified based on O. hupensis snail density data and the related NDVI. RESULTS: The surface area of Poyang Lake was approximately 2207 km2 in May 2020 before the flood and 4403 km2 in July 2020 during the period of peak flooding; this was estimated to be a 99.5% expansion of the water body due to flooding. After the flood, potential snail habitats were predicted to be concentrated in areas neighboring existing habitats in the marshlands of Poyang Lake. The areas with high risk of schistosomiasis transmission were predicted to be mainly distributed in Yongxiu, Xinjian, Yugan and Poyang (District) along the shores of Poyang Lake. By comparing the predictive results and actual snail distribution, we estimated the predictive accuracy of the model to be 87%, which meant the 87% of actual snail distribution was correctly identified as snail habitats in the model predictions. CONCLUSIONS: Data on water body expansion due to flooding and environmental factors pertaining to snail breeding may be rapidly extracted from Landsat 8 and Sentinel-1B remote sensing images. Applying multi-source remote sensing data for the timely and effective assessment of potential schistosomiasis transmission risk caused by snail spread during flooding is feasible and will be of great significance for more precision control of schistosomiasis.

[Comparative evaluation of five test kits for antibody detection in Schistosoma japonicum endemic areas of Poyang Lake region].

OBJECTIVE: To evaluate the efficacy of five diagnostic test kits for the detection of antibodies to Schistosoma japonicum in endemic areas of Poyang Lake. METHODS: Residents over 5 years old in three schistosomiasis-endemic administrative villages in the lake region were simultaneously examined by modified Kato-Katz thick smears and nylon bag sedimentation/hatching method. At the same time, five sero-diagnostic test kits for detection of IgG antibody against soluble egg antigen of S. japonicum were carried out. RESULTS: The distribution of seropositive rates of S. japonicum IgG antibodies determined by sero-diagnostic tests showed similar trends with that of egg positive rates in different age groups, but the seropositive rate (33.1%-57.1%) was significantly higher than that of egg positive rate (5.0%-8.2%), both reached a peak in 40-49-year-old group. The antibody positive rates determined by each test increased with the infection intensity. The sensitivity of the evaluated test kits ranged from 81.2%-94.5%. 26.9% to 46.1% among those egg negatives were antibody positive by the kits. Furthermore, 5.5%-18.8% of the egg positives were antibody negative by the kits. CONCLUSION: The five sero-diagnostic kits can be used for epidemiological survey in schistosomiasis endemic areas at community level. Among them, enzyme-linked immunosorbent assay shows higher sensitivity.

Impact of continuous low water stage on the breeding environment of Oncomelania hupensis: a case study of Poyang Lake area in China.

BACKGROUND: Oncomelania hupensis is the only intermediate host of Schistosoma japonicum and plays a decisive role in its transmission. The variation of water level greatly affects the reproduction and growth of snails. Therefore, in this paper, we analyze the variations of water level in the Poyang Lake region from 1993 to 2016 combined with satellite imagery to elucidate the evolution of the snail breeding environment. METHODS: By employing remote sensing data from 1993 to 2016 (April-June and September-November), the vegetation area of Poyang Lake and the vegetation area at different elevations were extracted and calculated. Moreover, the average daily water level data from the four hydrological stations (Hukou station, Xingzi station, Tangyin station and Kangshan station) which represent the typical state of Poyang Lake were collected from 1993 to 2016. The variance of the monthly mean water level, inundation time and the average area were analyzed by variance to find a significance level of α = 0.05. RESULTS: According to hydrological data before and after 2003, the average water level after 2003 is significantly lower than that before 2003 in Poyang Lake. After 2003, the time of inundateing the snail breeding period was later in April to June than that before 2003, while the time of wate-falling stage in September to November moved forward after 2003 than before 2003. Of them, the lowest water level affecting the breeding and growing period of O. hupensis in the northern part of Poyang Lake decreased from 11 m to 9 m. After 2003, the expansion of meadow area in the north part of Poyang Lake was mainly concentrated in the elevation of 9-11 m, and the newly increased infested-meadow in the lake area was mainly concentrated in the north part of Poyang Lake. CONCLUSIONS: By comparing the change of water level characteristics in different parts of the Poyang Lake area as well as changes in meadow area before and after 2003, it is found that the water level changes mainly affect the snail breeding area in the northern part of Poyang Lake. The results are helpful for improving scientific measures for snail control in Jiangxi Province. This approach could also be applicible to Dongting Lake area and other lake areas affected by water level changes and can bring significant guidance for snail control in lake areas.

Current trends and future prediction of novel coronavirus disease (COVID-19) epidemic in China: a dynamical modeling analysis.

The novel coronavirus disease 2019 (COVID-19) infection broke out in December 2019 in Wuhan, and rapidly overspread 31 provinces in mainland China on 31 January 2020. In the face of the increasing number of daily confirmed infected cases, it has become a common concern and worthy of pondering when the infection will appear the turning points, what is the final size and when the infection would be ultimately controlled. Based on the current control measures, we proposed a dynamical transmission model with contact trace and quarantine and predicted the peak time and final size for daily confirmed infected cases by employing Markov Chain Monte Carlo algorithm. We estimate the basic reproductive number of COVID-19 is 5.78 (95%CI: 5.71-5.89). Under the current intervention before 31 January, the number of daily confirmed infected cases is expected to peak on around 11 February 2020 with the size of 4066 (95%CI: 3898-4472). The infection of COVID-19 might be controlled approximately after 18 May 2020. Reducing contact and increasing trace about the risk population are likely to be the present effective measures.