Objective To investigate the development and dynamic changes of cysts in the brain of mice following infection with different forms of Toxoplasma gondii, so as to provide insights into for toxoplasmosis prevention and control. Methods ICR mice at ages of 6 to 8 weeks, each weighing 20 to 25 g, were intraperitoneally injected with tachyzoites of the T. gondii PRU strain at a dose of 1 × 10⁵ tachyzoites per mouse, orally administered with cysts at a dose of 20 oocysts per mouse or oocysts at a dose of 200 oocysts per mouse for modeling chronic T. gondii infection in mice, and the clinical symptoms and survival of mice were observed post-infection. Mice were orally infected with T. gondii cysts at doses of 10 (low-dose group), 20 (medium-dose group), 40 cysts per mouse (high-dose group), and the effect of different doses of T. gondii infections on the number of cysts was examined in the mouse brain. Mice were orally administered with T. gondii cysts at a dose of 20 cysts per mouse, and grouped according to gender (female and male) and time points of infections (20, 30, 60, 90, 120, 150, 180 days post-infection), and the effects of gender and time points of infections on the number of cysts was examined in the mouse brain. In addition, mice were divided into the tachyzoite group (Group T), the first-generation cyst group (Group C1), the second-generation cyst group (Group C2), the third-generation cyst (Group C3) and the fourth-generation cyst group (Group C4). Mice in the Group T were intraperitoneally injected with T. gondii tachyzoites at a dose of 1 × 10⁵ tachyzoites per mouse, and the cysts were collected from the mouse brain tissues 30 days post-infection, while mice in the Group C1 were orally infected with the collected cysts at a dose of 30 cysts per mouse. Continuous passage was performed by oral administration with cysts produced by the previous generation in mice, and the effect of continuous passage on the number of cysts was examined in the mouse brain. Results Following infection with T. gondii tachyzoites, cysts and oocysts in mice, obvious clinical symptoms were observed on days 6 to 13 and mice frequently died on days 7 to 12. The survival rates of mice were 67.0%, 87.0% and 53.0%, and the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0) and (581.0 ± 183.1) in the mouse brain (F = 11.94, P < 0.01) on day 30 post-infection with T. gondii tachyzoites, cysts and oocysts, respectively, and the numbers of cysts in the brain tissues were significantly lower in mice infected with T. gondii tachyzoites and oocysts than in those infected with cysts (all P values < 0.01). The survival rates of mice were 87.0%, 87.0% and 60.0%, and the mean numbers of cysts were (953.0 ± 355.5), (1 084.0 ± 474.3) and (1 113.0 ± 546.0) in the mouse brain in the low-, medium- and high-dose groups on day 30 post-infection, respectively (F = 0.42, P > 0.05). The survival rates of male and female mice were 73.0% and 80.0%, and the mean numbers of cysts were (946.4 ± 411.4) and (932.1 ± 322.4) in the brain tissues of male and female mice, respectively (F = 1.63, P > 0.05). Following continuous passage, the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0), (896.8 ± 332.3), (782.5 ± 423.9) and (829.2 ± 306.0) in the brain tissues of mice in the T, C1, C2, C3 and C4 groups, respectively (F = 4.82, P < 0.01), and the number of cysts was higher in the mouse brain in Group 1 than in Group T (P < 0.01). Following oral administration of 20 T. gondii cysts in mice, cysts were found in the moues brain for the first time on day 20 post-infection, and the number of cysts gradually increased over time, peaked on days 30 and 90 post-infection and then gradually decreased; however, the cysts were still found in the mouse brain on day 180 post-infection. Conclusions There is a higher possibility of developing chronic T. gondii infection in mice following infection with cysts than with oocysts or tachyzoites and the most severe chronic infection is seen following infection with cysts. The number of cysts does not correlate with the severity of chronic T. gondii infection, and the number of cysts peaks in the mouse brain on days 30 and 90 post-infection.

Objective:To compare the biomechanical properties of the modified and traditional iliolumbar pedicle screw-rod system for the fixation of vertically unstable posterior pelvic ring dislocation.Methods:The CT images of the lumbar spine, pelvis, and femur from a 31-year-old healthy male volunteer were used to establish models of posterior pelvic ring dislocation and unilateral and bilateral fixation models of modified and traditional iliolumbar pedicle screw-rod systems with the three-dimensional virtual software using the finite element method. By restraining the distal ends of the femurs of both sides and applying a vertical load of 500 N to the L 1 vertebral body, the maximum stress of the intact pelvis model and the stiffness of the posterior pelvic ring dislocation model were evaluated to validate the reliability of the models. After the validation of the models, a follower load of 400 N was applied in the direction of the L 1 vertebral curve to simulate the upper body weight; the maximum vertical displacement, the maximum posterior displacement, the maximum right displacement, and the overall maximum displacement of the sacrum of the modified and traditional iliolumbar pedicle screw-rod system models were compared. Additionally, stress distributions of the implant and the pelvis were also compared. Results:(1) The maximum stress of the intact pelvis model was 22.0 MPa, with the stiffness of the posterior pelvic ring dislocation model as 180.03 N/mm. (2) In terms of the maximum vertical displacement of the sacrum, the bilateral modified iliolumbar pedicle screw-rod system was similar to the bilateral traditional iliolumbar pedicle screw-rod system. However, the maximum posterior displacement, the maximum right displacement, and the overall maximum displacement of the sacrum in the bilateral modified iliolumbar pedicle screw-rod system were 0.57 mm, 0.19 mm and 0.68 mm respectively, which were markedly smaller than those of the bilateral traditional iliolumbar pedicle screw-rod system (1.38 mm, 0.26 mm and 1.41 mm respectively). (3) The maximum vertical displacement, the maximum posterior displacement, the maximum right displacement, and the overall maximum displacement of the sacrum in the unilateral modified iliolumbar pedicle screw-rod system were 0.70 mm, 0.73 mm, 0.17 mm and 0.88 mm respectively, which were markedly smaller than those of the unilateral traditional iliolumbar pedicle screw-rod system (1.17 mm, 2.21 mm, 0.31 mm and 2.29 mm respectively). (4) The stress of the implant was concentrated on the connecting rod between the iliac pedicle screw-rod and the lumbar pedicle screw-rod in the modified iliolumbar pedicle screw-rod system, but it was mainly concentrated on the connecting rod at the upper edge of the iliac screw in the traditional iliolumbar pedicle screw-rod system. The maximum stress of the implant was 340.84 MPa in the bilateral modified iliolumbar pedicle screw-rod system, which was 30.4% less than that in the bilateral traditional iliolumbar pedicle screw-rod system (489.77 MPa), and was 351.23 MPa in the unilateral modified iliolumbar pedicle screw-rod system, which was 15.5% less than that in the unilateral traditional iliolumbar pedicle screw-rod system (415.82 MPa). (5) In both modified and traditional iliolumbar pedicle screw-rod systems, the stress of the pelvis was concentrated on the contact area between the iliac screw and the cortical bone. The maximum stress of the pelvis was 19.21 MPa in the bilateral modified iliolumbar pedicle screw-rod system, which was 78.1% less than that in the bilateral traditional iliolumbar pedicle screw-rod system (87.59 MPa), and was 39.91 MPa in the unilateral modified iliolumbar pedicle screw-rod system, which was 70.4% less than that in the unilateral traditional iliolumbar pedicle screw-rod system (134.98 MPa).Conclusion:Compared with the traditional iliolumbar pedicle screw-rod system, the modified iliolumbar pedicle screw-rod system can effectively reduce the displacements of all directions in vertically unstable posterior pelvic ring dislocation and significantly reduce the stress of the implant and the pelvis, thus having good biomechanical stability.

Objective To investigate the seasonal Aedes population fluctuation and the resistance of Aedes populations to common insecticides in Jiangsu Province in 2020, so as to provide insights into vector-borne infectious diseases control.. Methods One village was randomly sampled from each of Xinbei District of Changzhou City and Zhangjiagang County of Suzhou City in southern Jiangsu Province, Hai’an County of Nantong City and Yandu District of Yancheng City in Central Jiangsu Province, and Suining County of Xuzhou City and Sihong County of Suqian City in northern Jiangsu Province during the period between May and October, 2020. A small ponding container was sampled, and larval Aedes mosquitoes were collected using straws once each in early and late stages of each month. All larvae were bred in laboratory to adults for population identification. In addition, larval breeding were observed in all small ponding containers in and out of 30 households that were randomly sampled from six surveillance sites, and the larval mosquito density was estimated using Breteau index. Larval A. albopictus mosquitoes were sampled around Cuiyuan New Village in Jintan District of Changzhou City, and bred in laboratory to the first offspring generation, and the susceptibility of adult female mosquitoes to deltamethrin, lambda-cyhalothrin, malathion, and propoxur was tested using the filter-paper bioassay recommended by WHO. Results A total of 1 165 larval Aedes mosquitoes were captured from small ponding containers in six surveillance sites of Jiangsu Province in 2020, and all were identified as A. albopictus following eclosion. The largest number of Aedes larvae captured was found in July. A total of 1 152 households were investigated in six surveillance sites, and the mean Breteau indexes were 9.58, 13.20, 13.71, 13.20, 12.18 and 5.58 from May to October, respectively, while a high Aedes transmission risk was seen in Xinbei District of Changzhou City, with a higher Breteau index than in Suining (H = 23.667, P_adjusted = 0.001) and Sihong (H = 22.500, P_adjusted = 0.003) counties. The field-captured A. albopictus from Cuiyuan New Village in Jintan District of Changzhou City remained sensitive to malathion, but was resistant to propoxur, and developed high-level resistance to deltamethrin and lambda-cyhalothrin. Conclusions A. albopictus was present in southern, central and northern Jiangsu Province in 2020, and the larval density peaked in July. A. albopictus captured from Cuiyuan New Village in Jintan District of Changzhou City has developed high-level resistance to pyrethroid pesticides.

Objective To quantitatively analyze the risk indicators of re-introduction of imported malaria in China and their weighting coefficients, so as to investigate the difference in the contribution of risk indicators included in the current risk assessment framework for re-introduction of imported malaria in China to the risk assessment of re-introduction of imported malaria. Methods Publications pertaining to the risk assessment framework for re-introduction of imported malaria in China that reported the risk indicators and their weighting coefficients were retrieved in PubMed, Web of Science, CNKI, Wanfang Data, and VIP with terms of “malaria”, “re-introduction/re-transmission/re-establishment”, “risk assessment/risk evaluation/risk prediction” from the inception of the database through 3 August 2023, and literature search was performed in Google Scholar to ensure the comprehensiveness of the retrieval. Basic characteristics of included studies were extracted using pre-designed information extraction forms by two investigators, and data pertaining to risk indicators of re-introduction of imported malaria were cross-checked by these two investigators. The risk indicators included in the risk assessment framework for re-introduction of imported malaria in China and their weighting coefficients were visualized with the Nightingale’s rose diagrams using the software R 4.2.1, and the importance of risk indictors was evaluated with the frequency of risk indicators included in the risk assessment framework and the ranking of weighting coefficients of risk indicators. In addition, the capability of risk indicators screened by different weighting methods was compared by calculating the ratio of the maximum to the minimum of the weighting coefficients of the risk indicators screened by different weighting methods. Results A total of 2 138 publications were retrieved, and following removal of duplications and screening, a total of 8 publications were included in the final analysis. In these 8 studies, 8 risk assessment frameworks for re-introduction of imported malaria in China and 52 risk indicators of re-introduction of imported malaria were reported, in which number of imported malaria cases (n = 8) and species of malaria vectors were more frequently included in the risk assessment frameworks (n = 8), followed by species of imported malaria parasites (n = 6) and population density of local malaria vectors (n = 6), and species of local malaria vectors (n = 6), number of imported malaria cases (n = 5) and species of imported malaria parasites had the three highest weighting coefficients (n = 4). The weighting methods included expert scoring method, combination of expert scoring method and analytic hierarchy process, and combination of expert scoring method and entropy weight method in these 8 studies, and the ratios of the maximum to the minimum of the weighting coefficients of the risk indicators screened by the expert scoring method were 1.143 to 2.241, while the ratios of the maximum to the minimum of the weighting coefficients of the risk indicators screened by combination of the expert scoring method and analytic hierarchy process were 34.970 to 162.000. Conclusions Number of imported malaria cases, species of imported malaria parasites, species of local malaria vectors and population density of local malaria vectors are core indicators in the current risk assessment framework for re-introduction of imported malaria in China. Combination of the expert scoring method and analytic hierarchy process is superior to the expert scoring method alone for weighting the risk indicators.

Objective To create risk predictive models of healthcare-seeking delay among imported malaria patients in Jiangsu Province based on machine learning algorithms, so as to provide insights into early identification of imported malaria cases in Jiangsu Province. Methods Case investigation, first symptoms and time of initial diagnosis of imported malaria patients in Jiangsu Province in 2019 were captured from Infectious Disease Report Information Management System and Parasitic Disease Prevention and Control Information Management System of Chinese Center for Disease Control and Prevention. The risk predictive models of healthcare-seeking delay among imported malaria patients were created with the back propagation (BP) neural network model, logistic regression model, random forest model and Bayesian model using thirteen factors as independent variables, including occupation, species of malaria parasite, main clinical manifestations, presence of complications, severity of disease, age, duration of residing abroad, frequency of malaria parasite infections abroad, incubation period, level of institution at initial diagnosis, country of origin, number of individuals travelling with patients and way to go abroad, and time of healthcare-seeking delay as a dependent variable. Logistic regression model was visualized using a nomogram, and the nomogram was evaluated using calibration curves. In addition, the efficiency of the four models for prediction of risk of healthcare-seeking delay among imported malaria patients was evaluated using the area under curve (AUC) of receiver operating characteristic curve (ROC). The importance of each characteristic was quantified and attributed by using SHAP to examine the positive and negative effects of the value of each characteristic on the predictive efficiency. Results A total of 244 imported malaria patients were enrolled, including 100 cases (40.98%) with the duration from onset of first symptoms to time of initial diagnosis that exceeded 24 hours. Logistic regression analysis identified a history of malaria parasite infection [odds ratio (OR) = 3.075, 95% confidential interval (CI): (1.597, 5.923)], long incubation period [OR = 1.010, 95% CI: (1.001, 1.018)] and seeking healthcare in provincial or municipal medical facilities [OR = 12.550, 95% CI: (1.158, 135.963)] as risk factors for delay in seeking healthcare among imported malaria cases. BP neural network modeling showed that duration of residing abroad, incubation period and age posed great impacts on delay in healthcare-seek among imported malaria patients. Random forest modeling showed that the top five factors with the greatest impact on healthcare-seeking delay included main clinical manifestations, the way to go abroad, incubation period, duration of residing abroad and age among imported malaria patients, and Bayesian modeling revealed that the top five factors affecting healthcare-seeking delay among imported malaria patients included level of institutions at initial diagnosis, age, country of origin, history of malaria parasite infection and individuals travelling with imported malaria patients. ROC curve analysis showed higher overall performance of the BP neural network model and the logistic regression model for prediction of the risk of healthcare-seeking delay among imported malaria patients (Z = 2.700 to 4.641, all P values < 0.01), with no statistically significant difference in the AUC among four models (Z = 1.209, P > 0.05). The sensitivity (71.00%) and Youden index (43.92%) of the logistic regression model was higher than those of the BP neural network (63.00% and 36.61%, respectively), and the specificity of the BP neural network model (73.61%) was higher than that of the logistic regression model (72.92%). Conclusions Imported malaria cases with long duration of residing abroad, a history of malaria parasite infection, long incubation period, advanced age and seeking healthcare in provincial or municipal medical institutions have a high likelihood of delay in healthcare-seeking in Jiangsu Province. The models created based on the logistic regression and BP neural network show a high efficiency for prediction of the risk of healthcare-seeking among imported malaria patients in Jiangsu Province, which may provide insights into health management of imported malaria patients.

Objective: Study the response of GMDTC to cadmium ions and metal ions in vivo to determine whether GMDTC are specifically complexed with cadmium ions to provide a reference for the safety and dfficacy of GMDTC. Methods: Complexometric titration, HPLC and HPLC-MS were applied to research the complexation reaction of GMDTC and various metal ions. The molecular ion peak of GMDTC, GMDTC-Cd complex and GMDTC-Pb complex also detected by LC-MS. Additionally, the initial structure was determined by DFT simulation method. Results: Results of complexometric titration and HPLC detection showed that GMDTC characteristic absorption peak area was proportional to the concentration of itself and there was no color change and peak time change when the GMDTC mixed with Ca²⁺, Fe²⁺, Mg²⁺, Zn²⁺. However, the color changed to black transition when the GMDTC mixed with Cu²⁺ and the color changed from yellow precipitate to light yellow transparent transition when GMDTC mix with Hg²⁺. Moreover, the peak area as well as the retention time has changed a lot which indicated that a chemical reaction has already happened. When the GMDTC mixed with Cd²⁺ and Pb²⁺, the color has changed from pale yellow to colorless transparent and the peak area of GMDTC has increased a lot. Finally, the GMDTC-Cd complex ratio both of which are 2:1 were calculated based on the results of LC-MS instrument and atomic calculations. Conclusion The specific cadmium chelating agent GMDTC can not react with the Ca²⁺, Fe²⁺, Mg²⁺, Zn²⁺, but it can react chemically with Cu²⁺ and Hg²⁺, even specific complex with Pb²⁺ and Cd²⁺.

Objective To understand the population,density,seasonal fluctuation and nocturnal pattern of malaria vectors in Jiangsu Province,thus to provide evidences for malaria elimination in this province. Methods Seven counties(cities,dis?tricts)were selected as the monitoring sites for malaria vectors in Jiangsu Province from 2013 to 2015. The mosquitoes were cap?tured by human bait trapping in bed nets and mosquito?lured lamp overnight,and the seasonal fluctuation and nocturnal pattern of malaria vectors were observed. Results A total of 11 041 Anopheles sinensis mosquitoes were captured by the mosquito?lured lamps in 7 counties of Jiangsu Province from 2013 to 2015,and no An. anthropophagous was found. Among all the 7 monitoring sites,the number of An. sinensis captured in Sihong County was the most(6 742 mosquitoes),while that in Xuyu County was the least(34 mosquitoes). During this period,the density peaks of An. sinensis were the first half of July,the first half of August and the second half of July. A total of 2 421 An. sinensis were collected in 7 monitoring sites from 2013 to 2015 by human bait trapping in bed nets overnight. Among all the 7 monitoring sites,the captured number of An. sinensis in Sihong County was the most(1 085 mosquitoes),while that in Ganyu County was the least(13 mosquitoes). The nocturnal peak of An. sinensis was from 19:00 to 20:00 and 525 An. sinensis mosquitoes were captured during this period of time,which accounted for 21.68%of the total. Hereafter,the captured number of An. sinensis reduced over time. Conclusion The density of An. sinensis mosquitoes is still high in individual areas in Jiangsu Province,so the epidemic and vector monitoring still should be strengthened to prevent the local transmission of imported malaria.

OBJECTIVETo study the population genetic variation, genetic diversity and phylogenesis of Anopheles sinensis in China.

METHODSAnopheles sinensis samples collected from Shandong, Anhui, Jiangsu, Guizhou, and Yunnan Provinces and Guangxi Zhuang Autonomous Region with different geographical conditions between 2010 and 2012 were analyzed by mitochondrial DNA cytochrome oxidase subunit I (mtDNA-COI) gene amplification and sequencing. Bioedit 7.0 and DnaSP 5.0 software was used to compare the gene sequences and analyze the population genetic structure, respectively. Arlequin 3.1 was used to calculate the genetic distance and parameters of population differentiation. The relationship between the geographic and genetic distances was analyzed using IBD Web Service. PHYLIP 3.6 was used to construct the phylogenetic tree.

RESULTSPCR amplification and sequencing was performed successfully for 6 Anopheles sinensis populations containing 123 female mosquitoes. The length of mtDNA-COI gene fragment was 841 bp with an average A+T content of 71.2% and G+C content of 28.8%. High nucleotide diversity and genetic differentiation were observed among the Anopheles sinensis populations based on mtDNA-COI gene. Analysis of the molecular variance revealed a greater variation between populations than that within populations with isolation by distance between the populations. The Anopheles sinensis populations appeared to have undergone expansion, but the Yunnan population constituted an isolated branch in the phylogenetic tree.

CONCLUSIONmtDNA-COI can serve as the molecular marker to analyze population genetic variation and phylogenesis of Anopheles sinensis. The Yunnan population shows a phylogenetic difference from the other populations analyzed in this study.

Animals ; Anopheles ; genetics ; China ; DNA, Mitochondrial ; genetics ; Electron Transport Complex IV ; genetics ; Female ; Genetic Variation ; Genetics, Population ; Phylogeny

Objective To explore the effect of different temperatures on the different development stages of Aedes albopic?tus. Methods The changes at different development stages of mosquitoes(egg,larva,pupae)and gonotrophic cycle were ob?served at different temperature conditions of 10,15,20,25,30,35℃and 40℃. The full developmental cycles were com?pared during different temperatures. Results All the stages of the mosquitoes could not develop at 10℃. Under the different temperatures of 15,20,25,30,35℃and 40℃,the hatchabilities of the mosquitoes were 0,32%,82%,83%,82%and 59%respectively;the pupation rates of the mosquitoes were 38%,53%,84%,88%,72%and 42%respectively;and the emer?gence rates of the mosquitoes were 92% 95% 97% 97% 83%and 17%respectively. The mosquitoes could well develop at 20 25 30℃and 35℃ the development time was 37.73 18.50 16.92 and 13.66 days respectively. Conclusion The devel?opment time of Aedes albopictus is shorter at the higher temperature. The optimum temperature for the mosquitoes to develop is between 25-30℃ and higher or lower the temperatures will suppress the development of the mosquitoes.

Objective To study the population genetic variation, genetic diversity and phylogenesis of Anopheles sinensis in China. Methods Anopheles sinensis samples collected from Shandong, Anhui, Jiangsu, Guizhou, and Yunnan Provinces and Guangxi Zhuang Autonomous Region with different geographical conditions between 2010 and 2012 were analyzed by mitochondrial DNA cytochrome oxidase subunit I (mtDNA-COI) gene amplification and sequencing. Bioedit 7.0 and DnaSP 5.0 software was used to compare the gene sequences and analyze the population genetic structure, respectively. Arlequin 3.1 was used to calculate the genetic distance and parameters of population differentiation. The relationship between the geographic and genetic distances was analyzed using IBD Web Service. PHYLIP 3.6 was used to construct the phylogenetic tree. Results PCR amplification and sequencing was performed successfully for 6 Anopheles sinensis populations containing 123 female mosquitoes. The length of mtDNA-COI gene fragment was 841 bp with an average A+T content of 71.2% and G+C content of 28.8%. High nucleotide diversity and genetic differentiation were observed among the Anopheles sinensis populations based on mtDNA-COI gene. Analysis of the molecular variance revealed a greater variation between populations than that within populations with isolation by distance between the populations. The Anopheles sinensis populations appeared to have undergone expansion, but the Yunnan population constituted an isolated branch in the phylogenetic tree. Conclusion mtDNA-COI can serve as the molecular marker to analyze population genetic variation and phylogenesis of Anopheles sinensis. The Yunnan population shows a phylogenetic difference from the other populations analyzed in this study.