Microevolution of Bartonella grahamii driven by geographic and host factors.

Bartonella grahamii is one of the most prevalent Bartonella species in wild rodents and has been associated with human cases of neuroretinitis. The structure and distribution of genomic diversity in natural B. grahamii is largely unexplored. Here, we have applied a comprehensive population genomic and phylogenomic analysis to 172 strains of B. grahamii to unravel the genetic differences and influencing factors that shape its populations. The findings reveal a remarkable genomic diversity within the species, primarily in the form of single- nucleotide polymorphisms. The open pangenome of B. grahamii indicates a dynamic genomic evolution influenced by its ecological niche. Whole-genome data allowed us to decompose B. grahamii diversity into six phylogroups, each characterized by a unique "mosaic pattern" of hosts and biogeographic regions. This suggests a complex interplay between host specificity and biogeography. In addition, our study suggests a possible origin of European strains from Asian lineages, and host factors have a more significant impact on the genetic differentiation of B. grahamii than geographical factors. These insights contribute to understanding the evolutionary history of this pathogen and provide a foundation for future epidemiological research and public health strategies. IMPORTANCE: Bartonella grahamii has been reported worldwide and shown to infect humans. Up to now, an effective transmission route of B. grahamii to humans has not been confirmed. The genetic evolution of B. grahamii and the relationship between B. grahamii and its host need to be further studied. The factors driving the genetic diversity of B. grahamii are still controversial. The results showed that the European isolates shared a common ancestor with the Chinese isolates. Host factors were shown to play an important role in driving the genetic diversity of B. grahamii. When host factors were fixed, geographic barriers drove B. grahamii microevolution. Our study emphasizes the importance of characterizing isolate genomes derived from hosts and geographical locations and provides a new reference for the origin of B. grahamii.

Transcriptome analysis of Kunming mice responses to the bite of Xenopsylla cheopis.

BACKGROUND: Flea bites could trigger a series of complex molecular responses in the host. However, our understanding of the responses at the molecular level is still relatively limited. This study quantifies the changes in gene expression in mice after flea bites by RNA sequencing (RNA-seq) from their spleens, revealing the potential biological effects of host response to flea bites. METHODS: RNA-seq was used for transcriptome analysis to screen for differentially expressed genes (DEGs) between the control mice group and the flea bite mice group. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed on DEGs. Protein-protein interaction (PPI) network analysis on DEGs related to immune processes was performed. Finally, we randomly selected several genes from the screened DEGs to validate the results from the transcriptome data by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). RESULTS: A total of 521 DEGs were identified, including 277 upregulated and 244 downregulated. There were 258 GO terms significantly enriched by upregulated DEGs and 419 GO terms significantly enriched by downregulated DEGs. Among the upregulated DEGs, 22 GO terms were associated with immune cells (e.g., B cells and T cells) and immune regulatory processes, while among the downregulated DEGs, 58 GO terms were associated with immune cells and immune regulatory processes. Through PPI analysis, we found that CD40 molecules with significantly downregulated expression levels after flea bites may play an important role in host immune regulation. Through KEGG pathway enrichment analysis, a total of 26 significantly enriched KEGG pathways were identified. The RT-qPCR analysis results indicated that the transcriptome sequencing results were reliable. CONCLUSIONS: Through in-depth analysis of transcriptome changes in mice caused by flea bites, we revealed that flea bites could stimulate a series of biological and immunological responses in mice. These findings not only provided a deeper understanding of the impact of flea bites on the host but also provided a basis for further research on the interaction between ectoparasites and the host. We believe that digging deeper into the significance of these transcriptome changes will help reveal more about the adaptive response of the host to ectoparasites.

High genetic diversity of the himalayan marmot relative to plague outbreaks in the Qinghai-Tibet Plateau, China.

Plague, as an ancient zoonotic disease caused by Yersinia pestis, has brought great disasters. The natural plague focus of Marmota himalayana in the Qinghai-Tibet Plateau is the largest, which has been constantly active and the leading source of human plague in China for decades. Understanding the population genetics of M. himalayana and relating that information to the biogeographic distribution of Yersinia pestis and plague outbreaks are greatly beneficial for the knowledge of plague spillover and arecrucial for pandemic prevention. In the present research, we assessed the population genetics of M. himalayana. We carried out a comparative study of plague outbreaks and the population genetics of M. himalayana on the Qinghai-Tibet Plateau. We found that M. himalayana populations are divided into two main clusters located in the south and north of the Qinghai-Tibet Plateau. Fourteen DFR genomovars of Y. pestis were found and exhibited a significant region-specific distribution. Additionally, the increased genetic diversity of plague hosts is positively associated with human plague outbreaks. This insight gained can improve our understanding of biodiversity for pathogen spillover and provide municipally directed targets for One Health surveillance development, which will be an informative next step toward increased monitoring of M. himalayana dynamics.

Climate heterogeneity, season variation, and sexual dimorphism modulate the association between MHC II diversity and parasite variation in striped hamster.

Parasite-mediated selection is widely believed to play a crucial role in maintaining the diversity of the major histocompatibility complex (MHC) genes, which is thought to be maintained through heterozygote advantage, rare-allele advantage, and fluctuating selection. However, the relationship between parasite pressure and MHC diversity has yielded inconsistent findings. These inconsistencies may arise from the influence of environmental factors and individual variations in traits on host-parasite interactions. To address these issues, our study extensively investigated populations of striped hamsters inhabiting regions characterized by environmental heterogeneity. The primary objective was to examine the universality of parasite-mediated selection mechanisms. Our observations revealed the presence of multiple parasite infections, accompanied by spatial and temporal variations in parasite communities and infection patterns among individual hamsters. Specifically, the temperature was found to influence all four parasite indices, while the presence of gamasid mites and parasite richness decreased with increasing precipitation. We also noted significant seasonal variation in parasite dynamics. Moreover, a significant sexual dimorphism was observed with males exhibiting a considerably higher parasite burden compared to their female counterparts. Lastly, we identified the maintenance of MHC polymorphism in striped hamsters as being driven by the heterozygote advantage and fluctuating selection mechanisms. This study underscores the significance of ecological processes in comprehending host-parasite systems and highlights the necessity of considering environmental factors and individual traits when elucidating the mechanisms underlying MHC diversity mediated by parasites.

Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation.

BACKGROUND: The major histocompatibility complex (MHC) plays a key role in the adaptive immune response to pathogens due to its extraordinary polymorphism. However, the spatial patterns of MHC variation in the striped hamster remain unclear, particularly regarding the relative contribution of the balancing selection in shaping MHC spatial variation and diversity compared to neutral forces. METHODS: In this study, we investigated the immunogenic variation of the striped hamster in four wild populations in Inner Mongolia which experience a heterogeneous parasitic burden. Our goal was to identify local adaptation by comparing the genetic structure at the MHC with that at seven microsatellite loci, taking into account neutral processes. RESULTS: We observed significant variation in parasite pressure among sites, with parasite burden showing a correlation with temperature and precipitation. Molecular analysis revealed a similar co-structure between MHC and microsatellite loci. We observed lower genetic differentiation at MHC loci compared to microsatellite loci, and no correlation was found between the two. CONCLUSIONS: Overall, these results suggest a complex interplay between neutral evolutionary forces and balancing selection in shaping the spatial patterns of MHC variation. Local adaptation was not detected on a small scale but may be applicable on a larger scale.

Spectrum-effect relationship study to reveal the pharmacodynamic substances in Flos Puerariae-Semen Hoveniae medicine pair for the treatment of alcohol-induced liver damage.

ETHNOPHARMACOLOGICAL RELEVANCE: Alcoholic liver disease (ALD) is the most serious and irreversible liver damage associated with alcohol consumption. Flos Puerariae and Semen Hoveniae are traditional Chinese medicines (TCM) for dispelling the effects of alcohol. Many studies have shown that the combination of two medicinal materials has the enhanced effect of treating ALD. AIM OF THE STUDY: The aim of this study is to assess the pharmacological effects of Flos Puerariae-Semen Hoveniae medicine pair, to elucidate its action mechanism in the treatment of alcohol-induced BRL-3A cells, and to reveal the active ingredients in the medicine pair that exerted pharmacological effects by spectrum-effect relationship study. MATERIALS AND METHODS: Firstly, MTT assays, ELISA, fluorescence probe analysis, and Western blot were employed to study the underlying mechanisms of the medicine pair in alcohol-induced BRL-3A cells by examining pharmacodynamic indexes and related protein expression. Secondly, HPLC method was established for chemical chromatograms of the medicine pair with different ratios and the sample extracted by different solvents. Then, principal component analysis, pearson bivariate correlation analysis and grey relational analysis were applied for development of the spectrum-effect correlation between pharmacodynamic indexes and HPLC chromatograms. Moreover, prototype components and their metabolites in vivo were identified by the HPLC-MS method. RESULTS: Flos Puerariae-Semen Hoveniae medicine pair remarkably increased cell viability, decreased the activity of ALT, AST, TC and TG, reduced the generation of TNF-α, IL-1ß, IL-6, MDA and ROS, increased the activity of SOD and GSH-Px, reduced protein expression of CYP2E1, compared with alcohol-induced BRL-3A cells. The medicine pair modulated the PI3K/AKT/mTOR signaling pathways by up-regulating the levels of phospho-PI3K, phospho-AKT and phospho-mTOR. Also, the results of the spectrum-effect relationship study showed that P1 (chlorogenic acid), P3 (daidzin), P4 (6″-O-xylosyl-glycitin), P5 (glycitin), P6 (unknown), P7 (unknown), P9 (unknown), P10 (6″-O-xylosyl-tectoridin), P12 (tectoridin) and P23 (unknown) can be considered as the main components of the medicine pair in the treatment of ALD. Furthermore, 6″-O-xylosyl-tectoridin, tectoridin, daidzin, 6″-O-xylosyl-glycitin and glycitin can be absorbed into the blood and showed clear metabolic and excretion behaviors in rats. CONCLUSION: In this study, the hepatoprotective effects and the pharmacology mechanism of Flos Puerariae-Semen Hoveniae medicine pair in alcohol-induced BRL-3A cells were initially investigated and revealed. Through the spectrum-effect relationship study, the potential pharmacodynamic constituents such as daidzin, 6″-O-xylosyl-glycitin, 6″-O-xylosyl-tectoridin, glycitin, and tectoridin exert pharmacological effects on alcohol-induced oxidative stress and inflammation by modulating the PI3K/AKT/mTOR signaling pathways. This study provided experimental basis and data support for revealing the pharmacodynamic substance basis and pharmacology mechanism in the treatment of ALD. Moreover, it provides a robust mean of exploring the primary effective components responsible for the bioactivity of complicated TCM.

Identification and expression of potential olfactory-related genes related to Niemann-Pick C2 protein and ionotropic receptors in Haemaphysalis longicornis.

Studies have shown that the main pathway for tick host localization and perception of mating information may be chemosensory. However, chemical communication in ticks is poorly understood, especially in those other than the Ixodes ticks. Niemann-Pick C2 (NPC2) protein and ionotropic receptors (IRs) are considered to be closely related to the perception of infochemicals in arthropods. Through bioinformatic analysis, eight NPC2 and four IR candidate genes were identified through screening and identification of the transcriptome sequencing database of Haemaphysalis longicornis. Phylogenetic tree analysis indicated that H. longicornis possesses similar homology to the genus Ixodes. A comparison of the expression of NPC2 and IR in tick forelegs (first pair of legs), hind legs (fourth pair of legs), and capitula using RT-PCR revealed that, barring HlonNPC2-8, 11 candidate genes were highly expressed in the foreleg and capitulum, which are the main sensory organs of ticks. They were also expressed in the hind legs, except for six genes that were not expressed in the males. RT-qPCR analysis showed upregulation and higher relative expression of HlonNPC2-1, HlonNPC2-3, HlonNPC2-6, and HlonNPC2-8 when stimulated by ammonium hydroxide, whereas the others were downregulated and demonstrated lower relative expression. These results further support the putative role of NPC2s as a new odorant carrier in ticks and present 12 promising candidate genes for understanding tick olfactory communication, enriching the data on these genes, especially outside the genus Ixodes.

Detection and genetic diversity of Bartonella species in small mammals from the central region of the Qinghai-Tibetan Plateau, China.

In this study, we aimed to investigate the prevalence and molecular characteristics of Bartonella infections in small mammals from the central region of the Qinghai-Tibetan Plateau. Toward this, small mammals were captured using snap traps in Yushu City and Nangqian County, West China, and the spleen tissue was used for Bartonella culture. The suspected positive colonies were evaluated using polymerase chain reaction (PCR) amplification and by sequencing the citrate synthase (gltA) gene. We discovered that 31 out of the 103 small mammals tested positive for Bartonella, with an infection rate of 30.10%. Sex differences between the mammals did not result in a significant difference in infection rate (χ2 = 0.018, P = 0.892). However, there was a significant difference in infection rates in different small mammals (Fisher's exact probability method, P = 0.017) and habitats (χ2 = 7.157, P = 0.028). Additionally, 31 Bartonella strains belonging to three species were identified, including B. grahamii (25), B. japonica (4) and B. heixiaziensis (2), among which B. grahamii was the dominant epidemic strain (accounting for 80.65%). Phylogenetic analyses showed that most of the B. grahamii isolates identified in this study may be closely related to the strains isolated from Japan and China. Genetic diversity analyses revealed that B. grahamii strains had high genetic diversity, which showed a certain host and geographical specificity. The results of Tajima's test suggested that the B. grahamii followed the progressions simulated by a neutral evolutionary model in the process of evolution. Overall, a high prevalence and genetic diversity of Bartonella infection were observed in small mammals in the central region of the Qinghai-Tibetan Plateau. B. grahamii as the dominant epidemic strain may cause diseases in humans, and the corresponding prevention and control measures should be taken into consideration in this area.

Knockdown resistance mutations distribution and characteristics of Aedes albopictus field populations within eleven dengue local epidemic provinces in China.

Background: Aedes albopictus, commonly known as the tiger mosquito, has attracted global attention because its bite can transmit several viruses, such as dengue virus. With the absence of an effective therapy and vaccine, mosquito control is the sole method for dengue fever control. However, Ae. albopictus has developed resistance to most insecticides, especially pyrethroids. Many scholars have conducted thorough research for the target-site of pyrethroids. The main target-site is the voltage-gated sodium channel gene (VGSC) whose mutation causes knockdown resistance (kdr). The spatial distribution of three locus kdr mutations in Ae. albopictus has not been comprehensively analyzed nationwide in China. In addition, the relationship between the frequency of kdr mutations and dengue fever has not yet been explored. Methods: A total of 2,241 Ae. albopictus samples from 49 populations from 11 provinces of mainland China were collected in 2020 and analyzed for mutations in the VGSC gene. DNAstar 7.1. Seqman and Mega-X were used to compare the sequences and read the peak map to confirm the genotypes and alleles of each mutation. ArcGIS 10.6 software was used to make interpolation and extract meteorological data of collection sites and to conduct spatial autocorrelation analysis. R 4.1.2 software was used to conduct a chi-square test for kdr mutations and dengue area and to analyze the correlation between meteorological factors and kdr mutations. Results: The overall frequencies of mutant alleles at 1016G, 1532T, and 1534S/C/L were 13.19%, 4.89%, and 46.90%, respectively. Mutations at the three loci were found at 89.80% (44/49), 44.90% (22/49), and 97.96% (48/49) of the field populations. At each of the loci V1016 and I1532, only one allele was detected, which was GGA(G) and ACC(T), respectively. Five mutant alleles were found at codon 1534: TCC/S (33.49%), TGC/C (11.96%), TTG/L (0.60%), CTC/L (0.49%), and TTA/L (0.58%). In total, 31 triple-locus genotype combinations were found, and the single locus mutation was the most common. We also found firstly triple-locus mutant individuals, whose genotypes were V/G+I/T+F/S and V/G+I/T+S/S. The 1016 and 1532 mutation rates were significantly negatively related to the annual average temperature (AAT), but the 1534 mutation rate was significantly positively related to AAT. The 1532 mutation rate was significantly positively related to the 1016 mutation rate but negatively related to the 1534 mutation rate. A relationship was observed between the 1534 codon mutation rate and dengue epidemic areas in this study. Furthermore, spatial autocorrelation analysis results showed that the mutation rates of different codons in different geographical areas had spatial aggregation and positive spatial correlation. Conclusion: This study showed that the multiple kdr mutations at codon 1016, 1532 and 1534 of Ae. albopictus were found in most areas of China. Two novel triple-locus genotype combinations, V/G+I/T+F/S and V/G+I/T+S/S, were detected in this study. In addition, the relationship between mosquito resistance and dengue fever outbreak should be further explored, especially considering the insecticide-usage history in different areas. The characteristic of spatial aggregation of VGSC gene mutation rates reminds us to notice the gene exchange and similarity of insecticide usage in the adjacent areas. The use of pyrethroids should be restricted to delay resistance development. New-type insecticides should be developed to adjust the changes in the resistance spectrum. Our study provides abundant data on the Ae. albopictus kdr gene mutation in China; these findings will be useful for the correlation analysis of molecular mechanism of insecticide resistance.

Entomological and Molecular Surveillance of Anopheles Mosquitoes in Freetown, Sierra Leone, 2019.

Background: Malaria is endemic in Sierra Leone, with stable and perennial transmission in all parts of the country. At present, the main prevention and control measures for mosquito vectors here involve insecticide treated nets (ITN) and indoor residual spraying (IRS). The most recent entomological surveillance was conducted prior to the civil war, between 1990 and 1994. Therefore, a new entomological surveillance required to support targeted malaria control strategies. Methods:Anopheles mosquitoes were collected between June and December 2019 using the light trap method. On these, we conducted species identification, analyzed seasonal fluctuation and Plasmodium infection rate, and monitored insecticide resistance. Results: Surveillance of seasonal fluctuation showed that there were two peak of Anopheles density in July (mean 13.67 mosquitoes/trap/night) and October (mean 13.00 mosquitoes/trap/night). Meanwhile, the lowest Anopheles density was seen in early September. Ninety-one representatives of Anopheles gambiae s.l. were selected and identified as An. coluzzii (n = 35) and An. gambiae s.s. (n = 56) using PCR. An. coluzzii and An. gambiae s.s. were found to be heterozygous resistant to the knockdown resistance (kdr) L1014F mutation (100%). Meanwhile, the East African mutation (kdr L1014S) was absent in the tested mosquitoes. Three mosquitoes that tested positive for the parasite, had an individual Plasmodium falciparum infection rate of 12.50, 16.67, and 14.29%. The sampling dates of positive mosquitoes were distributed in the two periods of peak Anopheles mosquito density. Conclusion: This study identified the dominant Anopheles species in Freetown as An. gambiae while the predominant species within the An. gambiae complex was An. gambiae sensu stricto. Surveillance of seasonal fluctuations and high P. falciparum infection rates in Anopheles indicate that the alternation of drought and rainy seasons from June to July, and from October to November, are the key periods for malaria control and prevention in Freetown, Sierra Leone. The high frequency of kdr allele mutations in An. gambiae calls for close monitoring of vector susceptibility to insecticides and tracing of resistance mechanisms in order to develop more effective vector control measures and strategies.

Genetic diversity of Bartonella species in small mammals in the Qaidam Basin, western China.

Investigation of the prevalence and diversity of Bartonella infections in small mammals in the Qaidam Basin, western China, could provide a scientific basis for the control and prevention of Bartonella infections in humans. Accordingly, in this study, small mammals were captured using snap traps in Wulan County and Ge'ermu City, Qaidam Basin, China. Spleen and brain tissues were collected and cultured to isolate Bartonella strains. The suspected positive colonies were detected with polymerase chain reaction amplification and sequencing of gltA, ftsZ, RNA polymerase beta subunit (rpoB) and ribC genes. Among 101 small mammals, 39 were positive for Bartonella, with the infection rate of 38.61%. The infection rate in different tissues (spleens and brains) (χ2 = 0.112, P = 0.738) and gender (χ2 = 1.927, P = 0.165) of small mammals did not have statistical difference, but that in different habitats had statistical difference (χ2 = 10.361, P = 0.016). Through genetic evolution analysis, 40 Bartonella strains were identified (two different Bartonella species were detected in one small mammal), including B. grahamii (30), B. jaculi (3), B. krasnovii (3) and Candidatus B. gerbillinarum (4), which showed rodent-specific characteristics. B. grahamii was the dominant epidemic strain (accounted for 75.0%). Furthermore, phylogenetic analysis showed that B. grahamii in the Qaidam Basin, might be close to the strains isolated from Japan and China. Overall, we observed a high prevalence of Bartonella infection in small mammals in the Qaidam Basin. B. grahamii may cause human disease, and the pathogenicity of the others Bartonella species needs further study, the corresponding prevention and control measures should be taken into consideration.

Diabetes mortality burden attributable to short-term effect of PM10 in China.

Ambient air pollution may be associated with diabetes mellitus. However, evidence from developing countries is limited although the concentrations of air pollution are disproportionably higher in these countries. We collected daily data on diabetes mortality, air pollution, and weather conditions from 16 Chinese provincial cities during 2007-2013. A quasi-Poisson regression combined with a distributed lag model was used to quantify the city-specific mortality risk of PM10 (particulate matter with aerodynamic diameter < 10 µm). Then, a random-effect meta-analysis was conducted to pool effect estimates from 16 cities. We also calculated the attributable fraction and attributable number of diabetes mortality due to PM10. Effects of PM10 were found to be acute and limited to 3 days. Harvesting effect of PM10 was found during lag 4-10 days on diabetes mortality. An increase of 0.17% (95%CI: 0.01-0.34), 0.48% (95%CI: 0.22-0.73), and 0.53% (95%CI: 0.27-0.80) in diabetes mortality was associated with per 10 µg/m3 increase in PM10 at lag 0, 0-4 and 0-10 days, respectively. Totally, 5.76% (95%CI: 2.59-8.00%) and 5878 (95%CI: 2639-8163) deaths due to diabetes could be attributable to PM10. If the concentration of PM10 attained the Chinese government and WHO targets, the reduction in number of PM2.5-attributed diabetes deaths was 2016 and 5528, respectively. Higher effect estimates of PM10 were observed among females and those aged 0-64 years old at lag 0 day, while greater cumulative effects of PM10 were among males, the elderly aged 75 or over, and the illiterate at lag 0-10 days. However, the between-group differences were not statistically significant. It is one of the few studies on examining the attributable burden of diabetes mortality caused by particulate matter. Our findings indicated that effective efforts on controlling air pollution could reduce a prominent number of air pollution-related diabetes deaths.

Interactions and marginal effects of meteorological factors on haemorrhagic fever with renal syndrome in different climate zones: Evidence from 254 cities of China.

BACKGROUND: Haemorrhagic fever with renal syndrome (HFRS) is climate sensitive. HFRS-weather associations have been investigated by previous studies, but few of them looked into the interaction of meteorological factors on HFRS in different climate zones. OBJECTIVE: We aim to explore the interactions and marginal effects of meteorological factors on HFRS in China. METHODS: HFRS surveillance data and meteorological data were collected from 254 cities during 2006-2016. A monthly time-series study design and generalized estimating equation models were adopted to estimate the interactions and marginal effects of meteorological factors on HFRS in different climate zones of China. RESULTS: Monthly meteorological variables and the number of HFRS cases showed seasonal fluctuations and the patterns varied by climate zone. We found that maximum lagged effects of temperature on HFRS were 1-month in temperate zone, 2-month in warm temperate zone, 3-month in subtropical zone, respectively. There is an interaction effect between mean temperature and precipitation in temperate zone, while in warm temperate zone the interaction effect was found between mean temperature and relative humidity. CONCLUSION: The interaction effects and marginal effects of meteorological factors on HFRS varied from region to region in China. Findings of this study may be helpful for better understanding the roles of meteorological variables in the transmission of HFRS in different climate zones, and provide implications for the development of weather-based HFRS early warning systems.

Establishment of an innovative and sustainable PCR technique for 1534 locus mutation of the knockdown resistance (kdr) gene in the dengue vector Aedes albopictus.

BACKGROUND: Mutation of the voltage-gated sodium channel (VGSC) gene, or knockdown resistance (kdr) gene, is an important resistance mechanism against DDT and pyrethroids for dengue vector Aedes albopictus. A phenylalanine to serine (F1534S), leucine (F1534L) and cysteine (F1534C) substitution were detected in many Ae. albopictus populations around the world, and the mutant allele frequencies have been increasing in recent years. Therefore, it is essential to establish a simple, time-saving and cost-effective procedure to monitor the alleles in large-scale studies. METHODS: Based on the mutation genotypes of the 1534 locus in the kdr gene, F/F, F/S, F/C, F/L, S/S, C/C, L/L and S/C, we designed specific forward and reverse primers and optimized the reaction conditions for establishing of the allele-specific PCR(AS-PCR) detection technique. DNA sequencing in this study was taken as the gold standard, and used to determine the accuracy of AS-PCR. RESULTS: The designed AS-PCR technique showed high specificity for distinguishing the mutations at the 1534 locus, as the accuracy for F/F, F/S, F/C, F/L, S/S, C/C and S/C were 100%, 95.35%, 100%, 100%, 100%, 100% and 100%, respectively. CONCLUSIONS: The designed AS-PCR technique effectively distinguished individual genotypes for the mutations at the 1534 locus in the kdr gene, which could facilitate the knockdown resistance surveillance in Ae. albopictus in large-scale studies.

The driver of dengue fever incidence in two high-risk areas of China: A comparative study.

In China, the knowledge of the underlying causes of heterogeneous distribution pattern of dengue fever in different high-risk areas is limited. A comparative study will help us understand the influencing factors of dengue in different high-risk areas. In the study, we compared the effects of climate, mosquito density and imported cases on dengue fever in two high-risk areas using Generalized Additive Model (GAM), random forests and Structural Equation Model (SEM). GAM analysis identified a similar positive correlation between imported cases, density of Aedes larvae, climate variables and dengue fever occurrence in the studied high-risk areas of both Guangdong and Yunnan provinces. Random forests showed that the most important factors affecting dengue fever occurrence were the number of imported cases, BI and the monthly average minimum temperature in Guangdong province; whereas the imported cases, the monthly average temperature and monthly relative humidity in Yunnan province. We found the rainfall had the indirect effect on dengue fever occurrence in both areas mediated by mosquito density; while the direct effect in high-risk areas of Guangdong was dominated by temperature and no obvious effect in Yunnan province by SEM. In total, climate factors and mosquito density are the key drivers on dengue fever incidence in different high-risk areas of China. These findings could provide scientific evidence for early warning and the scientific control of dengue fever in high-risk areas.

Development and comparison of forecast models of hand-foot-mouth disease with meteorological factors.

Hand-foot-mouth disease (HFMD) is an acute intestinal virus infectious disease which is one of major public health problems in mainland China. Previous studies indicated that HFMD was significantly influenced by climatic factors, but the associated factors were different in different areas and few study on HFMD forecast models was conducted. Here, we analyzed epidemiological characteristics of HFMD in Yiwu City, Zhejiang Province and constructed three forecast models. Overall, a total of 32554 HFMD cases were reported and 12 cases deceased in Yiwu City, Zhejiang Province. The incidence of HFMD peaked every other year and the curve of HFMD incidence had an approximately W-shape. The majority of HFMD cases were children and 95.76% cases aged ≤5 years old from 2008 to 2016. Furthermore, we constructed and compared three forecast models using autoregressive integrated moving average (ARIMA) model, negative binomial regression model (NBM), and quasi-Poisson generalized additive model (GAM). All the three models had high agreements between predicted values and observed values, while GAM fitted best. The exposure-response curve of monthly mean temperature and HFMD was approximately V-shaped. Our study explored epidemiological characteristics of HFMD in Yiwu City and provided accurate methods for early warning which would be great importance for the control and prevention of HFMD.

A molecular survey of Anaplasma, Ehrlichia, Bartonella and Theileria in ticks collected from southeastern China.

To investigate the prevalence of Anaplasma, Ehrlichia, Bartonella and Theileria, we collected ticks from small mammals in six counties of Zhejiang Province in southeastern China. Polymerase chain reaction (PCR) amplification was performed to test Anaplasma, Ehrlichia, Bartonella and Theileria in tick samples. Positive PCR products were sequenced and then compared with previously published sequences deposited in GenBank using BLAST. About 292 adult ticks were captured and the dominant tick species were Ixodes sinensis and Haemaphysalis longicornis. Overall, 34 ticks (11.6%) were tested positive for at least one pathogen of Anaplasma, Ehrlichia, Bartonella and Theileria. Rates of PCR-positivity to Anaplasma, Ehrlichia, Bartonella and Theileria were 5.5, 1.7, 2.4 and 2.4%, respectively. Positive rates of Anaplasma, Bartonella and Theileria were significantly different among ticks of different species. Prevalence of Anaplasma and Theileria varied significantly among ticks of different counties. Anaplasma, Ehrlichia, Bartonella and Theileria were widely prevalent in ticks in Zhejiang Province suggesting other tick-borne pathogens should also be suspected if patients had history of tick bites.

Cold spell and mortality in 31 Chinese capital cities: Definitions, vulnerability and implications.

BACKGROUND: In the context of global warming, most researches have been conducted on health influences of heat waves, with limited understanding of health impacts of cold spells, especially for developing countries. METHODS: We collected daily mortality and meteorological data for 31 capital cities across China during the maximum period of 2007-2013. A quasi-Poisson regression model combined with a distributed lag non-linear model was used to estimate the short-term effects of cold spells on mortality in cold seasons (November to March). 19 definitions of cold spell were clearly compared, including three definitions from the China Meteorological Administration (CMA) and 16 definitions by combining two temperature indicators (daily minimum and mean temperature), two temperature thresholds (3rd and 5th percentile) and four durations of at least 2-5 days. Then, a random effect meta-analysis was applied to pool the effect estimates at national level. Furthermore, a stratified analysis was constructed to identify the vulnerable subpopulations to cold spells. RESULTS: The definition, in which daily mean temperature falls below 5th percentile for at least two consecutive days, produced the optimum model fit performance. Generally, the mortality risk increased to the maximum after 3-6 days' exposure to cold spell and then leveled off in the next 3 weeks. The pooled relative risks (RR) of non-accidental mortality for cold spells were 1.03 (95% CI: 1.01-1.05), 1.27 (1.19-1.35) and 1.55 (1.40-1.70) at lag 0, lag 0-14 and lag 0-27 days, respectively. The greatest effect estimates of cold spells were found among total respiratory diseases and COPD, with RR of 1.88 (1.65-2.11) and 1.88 (1.58-2.19), respectively. The elderly, less-educated individuals and residents in southern China were more vulnerable to cold spells. CONCLUSION: There are remarkable mortality effects of cold spells, with effect estimates varying with the definition of cold spell and subpopulations. Using the official definition of cold spells may fail to capture the mortality risk associated with cold spells. These findings may facilitate the development of cold alert warning system and preventive actions to the vulnerable populations.

Psychoeducation for psychiatric inpatients following remission of a manic episode in bipolar I disorder: A randomized controlled trial.

OBJECTIVE: The aim of the present study was to evaluate the effectiveness of psychoeducation for bipolar I inpatients following remission of a manic episode in a Chinese population. METHOD: The study recruited currently medicated bipolar I patients, aged 18-60 years, who were in remission from a manic episode, as determined using the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5). Patients were randomized (1:1) to either eight sessions of group-based psychoeducation (active treatment group) or regular free discussions (control group). The primary outcomes were the rates of any type of recurrence and rehospitalization following treatment. The secondary outcomes were changes in mood symptoms, medication adherence, global functioning, as well as treatment response (as measured using the Clinical Global Impression scale). Subjects were assessed at baseline and then at 2 weeks, and 1, 2, 3, 5, 7, 9, and 12 months following treatment. RESULTS: At 1 year, patients receiving the psychoeducation treatment demonstrated significantly less recurrence. Those in the treatment group also showed a significant reduction in mania recurrence but not depressive recurrence, and psychoeducation increased time to remission. Notably, lower rates of rehospitalization were found in the active treatment group. Those receiving the psychoeducation treatment also revealed higher change from baseline on measures of depression (17-item Hamilton Rating Scale for Depression), mania (Young Mania Rating Scale), global functioning (Clinical Global Impression-severity scale and World Health Organization Disability Assessment Schedule) (P<.05). However, there were no significant group differences for the medication adherence scores. CONCLUSION: This preliminary evidence suggests that short, group-based psychoeducation benefits currently medicated inpatients following the remission of mania in bipolar I disorder. This intervention warrants further investigation, especially in other Chinese populations. If future studies confirm its benefits, group-based psychoeducation could be incorporated into routine psychiatric inpatient care for bipolar patients in China.