Loading...

Table of Content

    30 April 2021, Volume 33 Issue 2
    Intensified surveillance promotes the process towards elimination of schistosomiasis in China
    ZHANG Shi-Qing
    2021, 33(2):  107. 
    Asbtract ( )   PDF (974KB) ( )  
    Related Articles | Metrics
    Surveillance is an important part of the national schistosomiasis control program of China, which play a critical role in facilitating the progress towards elimination of schistosomiasis in China. The coverage of schistosomiasis surveillance has shifted from the high?risk regions at the initial stage of the national schistosomiasis control program of China to the current all endemic counties (cities, districts), and the surveillance contents have extended from single surveillance of endemic status to comprehensive surveillance of endemic status, epidemic factors and transmission risks. With the continuous progress towards schistosomiasis elimination, the national schistosomiasis control program has shifted from “extensive control” to surveillance and early warning?based “precision control” in China, which proposes much higher requirements for schistosomiasis surveillance. Currently, the surveillance of schistosomiasis has been covered in all schistosomiasis?endemic counties (cities, districts) of China, and the development of rapid and early identification of Schistosoma japonicum cercariae and S. japonicum?infected Oncomelania hupensis snails will greatly improve the sensitivity of and the duration of responses to schistosomiasis surveillance, which will provide powerful tools for elimination of schistosomiasis in China.
    Progress of researches on traveler's diarrhea caused by parasitic infections
    XU Jie, CAO Jian-Ping, SHEN Yu-Juan
    2021, 33(2):  110. 
    Asbtract ( )   PDF (1073KB) ( )  
    Related Articles | Metrics
    With the rapid development of global tourism, traveling gradually becomes an important part of daily lives, and travelers’ health is paid more and more attention. Traveler’s diarrhea (TD) is one of the most common diseases among international or trans?regional travelers, which causes great disease and economic burdens. Currently, there is still a lack of systematic studies on the correlation between parasites and TD. The review mainly summarizes intestinal protozoa and helminth infections among patients with TD, so as to provide insights into the development of the control measures for parasitic diseases associated with TD and the prevention of risk factors before the journey to and during the journey of the areas endemic for parasitic diseases.
    National surveillance of schistosomiasis morbidity in China, 2015—2019
    DANG Hui, LI Yin-Long, GUO Jing-Yi, XU Jing, LI Shi-Zhu, Lü Shan
    2021, 33(2):  120. 
    Asbtract ( )   PDF (1184KB) ( )  
    Related Articles | Metrics
    Objective To understand the morbidity due to Schisotsoma japonicum in national schistosomiasis surveillance sites of China from 2015 to 2019, so as to provide insights into schistosomiasis control and elimination and provide the scientific evidence for formulating the new scheme for schistosomiasis surveillance in China. Methods According to the requirements of National Scheme for Schistosomiasis Surveillance in China (2014 Edition), national schistosomiasis surveillance sites were assigned in all schistosomiasis?endemic counties (cities, districts) and the potential endemic counties (cities, districts) in the Three Gorges Reservoir areas, and S. japonicum infections were monitored in local residents, mobile populations and livestock according to different epidemic types. The sero?prevalence of S. japonicum infections, adjusted prevalence of human S. japonicum infections, characteristics of egg?positive individuals and prevalence of S. japonicum infections livestock were analyzed. Results  S. japonicum infections were monitored in 453 schistosomiasis?endemic counties (cities, districts) from 13 provinces (municipalities, autonomous regions) and 4 potential endemic counties (cities, districts) from the Three Gorges Reservoir areas in China from 2015 to 2019. During the 5?year period from 2015 to 2019, the sero?prevalence of S. japonicum infections reduced from 3.35% to 1.63% among local residents and from 1.15% to 0.75% among mobile populations, while the adjusted prevalence of infections reduced from 0.05% to 0 among local residents and from 0.20% to 0.001 03% among mobile populations. There were significant differences in the sero?prevalence of S. japonicum infections among local residents and mobile populations in terms of province, occupation and age (all P values < 0.05). A total of 132 egg?positives were identified during the 5?year period, including 97 local residents (inter?quartile range for ages, 47 to 61 years), and 35 mobile populations (inter?quartile range for ages, 26 to 48 years), and there was a significant difference in the age distribution between local residents and mobile populations. There were totally 6 bovines (5 in 2015 and 1 in 2016) identified with S. japonicum infections in national schistosomiasis surveillance sites of China, with no S. japonicum infections detected in bovines from 2017 to 2019. Conclusions The prevalence of schistosomiasis is very low in China. Further surveillance including more mobile surveillance sites seems justified to identify the risk of schistosomiasis as soon as possible and interrupt the transmission route, so as to facilitate the elimination of schistosomiasis in China.
    National surveillance of Oncomelania hupensis in China, 2015—2019
    LI Yin-Long, DANG Hui, GUO Su-Ying, CAO Chun-Li, Lü Shan, XU Jing, LI Shi-Zhu
    2021, 33(2):  127. 
    Asbtract ( )   PDF (1452KB) ( )  
    Related Articles | Metrics
    Objective To analyze the monitoring data of Oncomelania hupensis in the national schistosomiasis surveillance sites of China from 2015 to 2019, so as to understand the changes of Oncomelania snail status in the schistosomiasis?endemic areas of China and to provide the scientific evidence for Oncomelania snail control. Methods According to the requirements of National Scheme for Schistosomiasis Surveillance in China (2014 Edition), national schistosomiasis surveillance sites were assigned in all schistosomiasis?endemic counties (cities, districts) and the potential endemic counties (cities, districts) in the Three Gorges Reservoir areas, and Oncomelania snail status was monitored according to different epidemic types. In endemic areas, Oncomelania snail survey was performed by means of systematic sampling and environmental sampling, and the occurrence of frames with Oncomelania snails and the prevalence of Schistosoma japonicum infections in Oncomelania snails were calculated, while in potential endemic areas, the risk of imported Oncomelania snails and Oncomelania snails in floating debris were monitored. Results Oncomelania snail survey was performed covering an area of 116 834.16 hm2 in the national schistosomiasis surveillance of China from 2015 to 2019, with 35 007.62 hm2 Oncomelania snail habitats identified. A total of 6 908 292 frames were surveyed during the 5?year period, and there were 364 555 frames detected with Oncomelania snails, with a 5.28% mean occurrence of frames with Oncomelania snails. Among 997 508 living Oncomelania snails captured, no S. japonicum infections were detected, and loop?mediated isothermal amplification (LAMP) assay detected 18 positive mixed Oncomelania snail samples. During the period from 2015 to 2019, 147.20 hm2 emerging Oncomelania snail habitats were identified, with an overall tendency towards a rise seen in the proportion of emerging Oncomelania snail habitats in plain regions with waterway networks (0.12% to 92.00%), a tendency towards a rise followed by decline seen in marshland and lake regions (0 to 96.72%), and a large fluctuation in hilly regions (0 to 88.49%). A total of 831.10 hm2 re?emerging Oncomelania snail habitats were found in the national schistosomiasis surveillance sites of China from 2015 to 2019, with an overall tendency towards a rise seen in the proportion of re?emerging Oncomelania snail habitats in marshland and lake regions (16.05% to 79.66%), an overall tendency towards a decline seen in hilly regions (19.25% to 81.00%), and a minor fluctuation in plain regions with waterway networks (1.10% to 10.14%). During the 5?year period from 2015 to 2019, a total of 48 656 kg floating debris were captured in 4 surveillance sites in the Three Gorges Reservoir areas, and 2 204 snails were found, with no Oncomelania snails identified. Conclusions The areas of Oncomelania snail habitats tended to be stable in the national schistosomiasis surveillance sites of China during the period from 2015 to 2019, however, there was a gradual rise in the area of Oncomelania snail habitats year by year, and LAMP assay identified positive Oncomelania snail samples, suggesting Oncomelania snail control is far from optimistic in China.
    Construction of a forecast system for prediction of schistosomiasis risk in China based on the flood information
    ZHENG Jin-Xin, XIA Shang, Lü Shan, ZHANG Yi, ZHOU Xiao-Nong
    2021, 33(2):  133. 
    Asbtract ( )   PDF (1747KB) ( )  
    Related Articles | Metrics
    Objective To create a model based on meteorological data to predict the regions at risk of schistosomiasis during the flood season, so as to provide insights into the surveillance and forecast of schistosomiasis. Methods An interactive schistosomiasis forecast system was created using the open?access R software. The schistosomiasis risk index was used as a basic parameter, and the species distribution model of Oncomelania hupensis snails was generated according to the cumulative rainfall and temperature to predict the probability of O. hupensis snail distribution, so as to identify the regions at risk of schistosomiasis transmission during the flood season. Results The framework of the web page was built using the Shiny package in the R program, and an interactive and visualization system was successfully created to predict the distribution of O. hupensis snails, containing O. hupensis snail surveillance site database, meteorological and environmental data. In this system, the snail distribution area may be displayed and the regions at risk of schistosomiasis transmission may be predicted using the species distribution model. This predictive system may rapidly generate the schistosomiasis transmission risk map, which is simple and easy to perform. In addition, the regions at risk of schistosomiasis transmission were predicted to be concentrated in the middle and lower reaches of the Yangtze River during the flood period. Conclusions A schistosomiasis forecast system is successfully created, which is accurate and rapid to utilize meteorological data to predict the regions at risk of schistosomiasis transmission during the flood period.
    Conversion of serum anti-Schistosoma japonicum antibodies detected by immunological tests following treatment with praziquantel: a meta-analysis
    WANG Li-Ping, DENG Wang-Ping, JIA Tie-Wu, QIN Zhi-Qiang, XU Jing
    2021, 33(2):  138. 
    Asbtract ( )   PDF (2331KB) ( )  
    Related Articles | Metrics
    Objective To evaluate the conversion of serum antibodies against Schistosoma japonicum in humans and livestock detected by immunological tests following treatment with praziquantel. Methods The studies pertaining to serological tests of schistosomiasis japonica published from 1991 to 2020 were retrieved in electronic databases, including Chinese National Knowledge Infrastructure, WanFang Data, PubMed and ScienceDirect. Data were extracted from included studies. The publication bias was assessed with funnel plots using the software RevMan version 5.3, and the conversion of antibodies against S. japonicum was evaluated through meta?analysis. Results A total of 40 publications were included in the final meta?analysis, consisting of 33 Chinese publications and 7 English publications, and all immunological tests were performed with indirect hemagglutination test (IHA) and enzyme?linked immunosorbent assay (ELISA). Pooled analysis showed that the negative rates of serum anti?S. japonicum antibody were 45.36% [95% confidential interval (CI): (43.96%, 46.76%)] and 20.83% [95% CI: (19.69%, 21.97%)] detected by ELISA and IHA within 6 months post praziquantel treatment, 62.95% [95% CI: (61.59%, 64.31%)] and 55.61% [95% CI: (54.21%, 57.01%)] within 6 to 12 months after treatment and 85.92% [95% CI: (84.94%, 86.90%)] and 86.90% [95% CI: (85.95%, 87.85%)] over 12 months after treatment, respectively. Conclusions The negative rate of the serum anti?S. japonicum antibody by IHA and ELISA increased with the time of post?treatment with praziquantel. The overall negative rates of anti?S. japonicum antibody detected by IHA and ELISA are low within 12 months post praziquantel treatment. However, a high negative rate of anti?S. japonicum antibody is detected if there is no new contact with infested water after 12 months of praziquantel treatment.
    Expression and clinicopathological significance of Bcl-2 and Bax genes in colorectal cancer patients complicated with schistosomiasis
    YANG Xing-Guang, YANG Ji-Wu, ZHAO Peng-Ju, CHENG Wei, SHI Hai-Bin, ZHANG Bin, FU Qi-Chun, LI Yi
    2021, 33(2):  148. 
    Asbtract ( )   PDF (1877KB) ( )  
    Related Articles | Metrics
    Objective To investigate the expression and clinicopathological significance of Bcl?2 and Bax genes in colorectal cancer (CRC) patients complicated with schistosomiasis. Methods The CRC patients receiving surgical treatment in the First Affiliated Hospital of Dali University from June 2016 to June 2020 were recruited as the study subjects, and 30 subjects were randomly sampled from the CRC patients complicated with schistosomiasis (CRC?S group) and 30 subjects were randomly sampled from the CRC patients without schistosomiasis (CRC group) using a random number table method. The cancer specimens were sampled from subjects in the CRC?S and CRC groups, and the peri?cancer specimens were sampled from subjects in the CRC group. The Bcl?2 and Bax expression was quantified in cancer and peri?cancer specimens using a real?time fluorescent quantitative PCR (qPCR) assay and immunohistochemistry at transcriptional and translational levels, and the cell apoptosis was detected in cancer specimens using HE staining. Results A total of 60 subjects were enrolled, including 30 cases in the CRC group and 30 cases in the CRC?S group. There were no significant differences between the two groups in terms of gender distribution ([χ2] = 0.271, P > 0.05), mean age (t = -0.596, P > 0.05), tumor growth pattern ([χ2] = 0.275, P > 0.05), tumor location ([χ2] = 4.008, P > 0.05), tumor invasion depth ([χ2] = 0.608, P > 0.05), degree of tumor differentiation ([χ2] = 0.364, P > 0.05), or presence of vascular metastasis ([χ2] = 1.111, P > 0.05), while significant differences were seen between the two groups in terms of histological type, presence of lymph node metastasis and TMN staging ([χ2] = 5.963, 8.297 and 5.711, all P values < 0.05). qPCR assay and immunohistochemistry quantified significantly higher Bcl?2 and Bax expression in cancer specimens from the CRC and CRC?S groups than in the peri?cancer specimens from the CRC group at both translational and transcriptional levels (all P values < 0.05), and higher Bcl?2 and lower Bax expression were seen in the cancer specimens from the CSC?S group than that from the CRC group (all P values < 0.05). In addition, the cell apoptotic rate was significantly greater in the cancer specimens in the CRC group than in the CRC?S group (42.00% vs. 23.35%; [χ2] = 41.500, P = 0.000). Conclusion Schistosomiasis may be involved in the development and progression of CRC through affecting Bcl?2 and Bax gene expression in the apoptosis signaling pathway.
    Study on the hospitalization cost and its influencing factors of imported malaria patients in Guangxi Zhuang Autonomous Region and Yunnan Province
    XU Qiu-Li, LIN Kang-Ming, YIN Shou-Qin, QIAN Men-Bao, WANG Duo-Quan, DUAN Lei, LU Shen-Ning, LI Yu-Xing, XIAO Ning
    2021, 33(2):  154. 
    Asbtract ( )   PDF (1235KB) ( )  
    Related Articles | Metrics
    Objective To analyze the hospitalization cost and its influencing factors of imported malaria patients in Guangxi Zhuang Autonomous Region and Yunnan Province, so as to provide insights into the evaluation of the economic burden due to imported malaria, and the guiding of malaria control and the rational allocation of medical resources. Methods The data pertaining to the hospitalization costs of imported malaria patients admitted to Shanglin County People’s Hospital in Guangxi Zhuang Autonomous Region during the period from January 1 through December 31, 2019, and Tengchong Municipal People’s Hospital in Yunnan Province from January 1, 2015 to December 31, 2019, were collected, and the epidemiological data of these imported malaria patients were extracted from the Information Management System for Parasitic Diseases Control and Prevention, China. The composition of the hospitalization expenses was analyzed using a descriptive method. In addition, the factors affecting the hospitalization expenses of imported malaria patients were identified using a univariate analysis and a recursive system model. Results A total of 206 imported malaria patients were included in this study, including 194 men (94.17%) and 12 women (5.83%). The mean length of hospital stay was 5.00 days per patient and the median hospitalization expenses were 2 813.07 Yuan per time, in which the expenses for laboratory examinations were the highest (45.31%, 1 274.62/2 813.07). Univariate analysis showed that hospital (z = 5.43, P < 0.01), type of malaria ([χ2] = 34.86, P < 0.01) and type of payment ([χ2] = 7.72, P < 0.05) were factors affecting the hospitalization expenses of imported malaria patients. Recursion system modeling revealed that the total effects on hospitalization expenses of imported malaria patients included length of hospital stay (0.78), selection of hospital (0.34), basic medical insurance for urban and rural residents (0.19), new rural cooperative medical care (0.17), Plasmodium falciparum malaria (0.15), gender (0.11) and P. vivax malaria (0.09). Conclusions The hospitalization expenses of imported malaria patients are affected by multiple factors in Guangxi Zhuang Autonomous Region and Yunnan Province, in which the length of hospital stay is the most predominant influencing factor. A reduction in the length of hospital stay is effective to decrease the hospitalization expenses of imported malaria patients.
    Assessment of the burden of clonorchiasis and its temporal changes in China
    ZHAO Ting-Ting, FANG Yue-Yi, LAI Ying-Si
    2021, 33(2):  162. 
    Asbtract ( )   PDF (1180KB) ( )  
    Related Articles | Metrics
    Objective To assess the burden of clonorchiasis and identify its temporal and spatial changes in China, thus to provide insights into the control and prevention of the diseases. Methods The disability?adjusted life years (DALYs) was employed as the primary indicator for the disease burden. The prevalence data of Clonorchis sinensis infection were obtainted from the three national surveys on important human parasitic diseases in China, conducting during the period from 1988 to 1922, from 2001 to 2004 and from 2014 to 2016, respectively, and the demographic data from National Bureau of Statistics of China. DALYs of clonorchiasis were calculated and the temporal changes were analyzed at both national and provincial levels, using the disability weight (DW) obtained from a community study in China. Sensitivity analysis was carried out to compare the resulted DALYs of China calculated under the method adopted in this study and that calculated with other commonly used methods. Results The national burden of clonorchiasis was 489 174.04 [95% confidence interval (CI): (391 648.87, 597 509.87)] DALYs in China in 2016, indicating 0.36 [95% CI: (0.28, 0.43)] DALYs per 1 000 populations. The regions with a high burden of clonorchiasis were concentrated in southern China and northeastern China, and the provinces with the three highest burdens of clonorchiasis included Guangxi Zhuang Autonomous Region, Guangdong Province and Heilongjiang Province, which accounted for 91.18% of total burdens of clonorchiasis in China. During the periods of the three national surveys on important human parasitic diseases in China, the national burden of clonorchiasis was found to show a tendency of first rise and then decrease in China; however, the burden of clonorchiasis has recently shown a tendency towards a rise in Guangxi Zhuang Autonomous Region, Heilongjiang Province and Jiangxi Province. Sensitivity analysis showed that the calculation of diseases burden with age?stratified prevalence of clonorchiasis was similar to that of our method without age stratification; however, the burden estimates calculated only based on the DW of the severe symptoms were much lower than our estimates. Conclusions The burden of clonorchiasis is high in China, with a large regional difference. Recently, the overall burden of clonorchiasis has shown a tendency of decline in China; however, there is a tendency towards a rise in some provinces. Therefore, the control of clonorchiasis requires more adaptations to local circumstances.
    Prediction of suitable habitats of Ixodes persulcatus in China
    MA Ben, MA Xiao-Yu, ZHANG Yi, CHEN Hui-Bo, WANG Qiang, LI Lan-Hua
    2021, 33(2):  169. 
    Asbtract ( )   PDF (1773KB) ( )  
    Related Articles | Metrics
    Objective To evaluate the effects of environmental factors the distribution of Ixodes persulcatus, and to predict the future suitable habitats of I. persulcatus in China. Methods The known distribution sites of I. persulcatus in China were captured from national and international published literatures. The effects of 14 environmental factors on the distribution of I. persulcatus were examined using the Jackknife test, including mean annual temperature, mean monthly temperature range, isothermality, temperature seasonality, maximum temperature of the warmest month, minimum temperature of the coldest month, temperature annual range, mean temperature of the wettest quarter, mean temperature of the driest quarter, mean temperature of the wettest quarter, mean temperature of the coldest quarter, annual mean precipitation, precipitation of the wettest month, precipitation of the driest month, precipitation seasonality, precipitation of the wettest quarter, precipitation of the driest quarter, precipitation of the warmest quarter, precipitation of the coldest quarter, elevation, slope, aspect and vegetation. The suitable habitats of I. persulcatus were predicted in China using the maximum entropy model and ArcGIS 10.7 software with the environmental factors. Results Currently, the highly suitable habitats of I. persulcatus covered an area of 886 600 km2 in China, which were predominantly located in northeastern China. The environmental factors that contributed more than 10% to the distribution of the suitable habitats of I. persulcatus in China included annual temperature variation range (39.1%), the coldest quarterly precipitation (23.2%), and the annual mean precipitation (11.9%). Based on the maximum entropy model, the suitable habitats of I. persulcatus were predicted to show a shrinking tendency towards northeastern China in 2070. Conclusions The suitable habitat of I. persulcatus strongly correlates with temperature and precipitation, and climate and environmental changes may lead to shrinking of the future suitable habitat of I. persulcatus in China.
    PD-1/PD-L1 expression and its interaction with interferon-γ in Toxoplasma gondii-infected mice at middle and late pregnancy
    XUE Sa, ZENG Yu-Lu, BI Xiang-Lian, LU Yun-Yu, ZHANG Da-Yi, ZHANG Li-Lin, HAN Xue, YANG Jun, FU Xiao-Yin, LIU Deng-Yu
    2021, 33(2):  177. 
    Asbtract ( )   PDF (1892KB) ( )  
    Related Articles | Metrics
    Objective To explore the dynamic expression of programmed cell death?1 (PD?1) and its ligand PD?L1 at the maternal?fetal interface of mice post?infection with Toxoplasma gondii at early pregnancy and examine its interaction with interferon?γ (IFN?γ). Methods A total of 20 mice at day 0 of pregnancy were randomly assigned into 4 groups, including the 12?day pregnancy control group (12 dpn group), 12?day pregnancy and infection group (12 dpi group), 18?day pregnancy control group (18 dpn group) and 18?day pregnancy and infection group (18 dpi group), respectively. On the 6th day of the pregnancy, mice in the 12 dpi and 18 dpi groups were injected intraperitoneally with 150 tachyzoites of the T. gondii PRU strain, while mice in the 12 dpn and 18 dpn groups were injected with the same volume of PBS. All mice in the four groups were sacrificed on 12th and 18th day of the pregnancy, and the number of placenta and fetus was counted and the weight of placenta and fetus was measured. Then, the placental and uterine tissues of the pregnant mice in each group were sampled for pathological examinations. The mRNA expression of PD?1, PD?L1, T. gondii surface antigen SAG?1 and IFN?γ genes was quantified using a quantitative real?time PCR (qPCR) assay, and the correlation between PD?1 and IFN?γ expression was examined. In addition, the 12 dpn group, 12 dpi group, 18 dpn group, 18 dpi group, PBS negative control of the 12 pdi group and PBS negative control of the 18 dpi group were assigned, and the PD?1 expression was determined in the uterine and placenta tissues of the pregnant mice. Results Adverse pregnant outcomes were seen in mice in the 12 dpi and 18 dpi groups, including placental dysplasia and fetal maldevelopment, and the placental weights and fetal body weights were significantly lower in mice in the 12 dpi and 18 dpi groups than those in the 12 dpn and 18 dpn groups (t = 5.52, 11.44, 12.63 and 11.67, all P < 0.01). The histopathological examinations showed that the decidua and junctional regions of the placental tissues were loosely connected in the 12 dpi and 18 dpi groups, and a large number of inflammatory cells infiltration and congestion were seen in the placental and uterine tissues. qPCR assay detected significant differences in PD?1, PD?L1, IFN?γ and SAG?1 expression in the placental and uterine tissues among the 12 dpn, 12 dpi, 18 dpn and 18 dpi groups (F = 22.48, 51.23, 9.61, 47.49, 16.08, 21.52, 28.66 and 238.90, all P < 0.05), and the PD?1, PD?L1, IFN?γ and SAG?1 expression was all significantly higher in the placental and uterine tissues of mice in the 12 dpi group than in the 12 dpn group (all P values < 0.05). The PD?1 and PD?L1 expression was significantly lower in the placental tissues of mice in the 18 dpi group than in the 18 dpn group (all P values < 0.05), and the IFN?γ and SAG?1 expression was significantly higher in the placental and uterine tissues of mice in the 18 dpi group than in the 18 dpn group (all P values < 0.05), while the PD?1 and PD?L1 expression was significantly lower in the placental and uterine tissues of mice in the 18 dpi group than in the 12 dpi group (all P values < 0.05). Immunohistochemical staining showed PD?1 expression in the inflammatory cells of the placental tissues of mice in the 12 dpi group, and no apparent PD?1 expression in the 18 dpi group, while strongly positive PD?1 expression was found in the uterine epithelium of mice in the 12 dpi group, and mildly strong expression was in the 18 dpi group. In addition, the IFN?γ mRNA expression was positively correlated with the PD?1 mRNA expression in placental (rs = 0.99, P < 0.01) and uterine tissues of mice in the 12 dpi group (rs = 0.97, P < 0.01) and in placental (rs = 0.82, P < 0.01) and uterine tissues of mice in the 18 dpi group (rs = 0.81, P < 0.01). Conclusions Following T. gondii infection at early pregnancy, the PD?1 and PD?L1 expression shows a remarkable rise at middle pregnancy and a reduction at late pregnancy in placental and uterine tissues of mice, which appears the same tendency with IFN?γ expression during the same time period, and PD?1 expression positively correlates with IFN?γ expression. The dynamic expression of PD?1 and PD?L1 on the maternal?fetal interface of mice may be mutually mediated by IFN?γ induced by T. gondii infection.
    Performance of a recombinase-aided amplification assay for detection of Schistosoma japonicum infections in Oncomelania hupensis
    YE Yu-Ying, ZHAO Song, LIU Yan-Hong, BI Nian-Nian, DONG Xuan, XIONG Chun-Rong, ZHU Hong-Ru, TANG Feng, WANG Xin-Yao, ZHANG Jian-Feng, YING Qing-Jie, YANG Kun
    2021, 33(2):  185. 
    Asbtract ( )   PDF (964KB) ( )  
    Related Articles | Metrics
    Objective To evaluate the efficiency of a recombinase?aided amplification (RAA) assay for the detection of Schistosoma japonicum infections in Oncomelania hupensis snails. Methods A group test was employed. Fifty Oncomelania snails were collected as a detection sample. The detection samples without infected snails were designated as negative specimens, while the detection samples that contained different numbers of infected snails were designated as positive specimens. A total of 10 negative specimens, 10 positive specimens containing 1 infected snail, 20 positive specimens containing 2 infected snails and 10 positive specimens containing 3 infected snails were assigned. Following random grouping, 40 specimens were subject to the florescent RAA assay using a blind method. The miradium shedding method served as a gold standard, and the sensitivity, specificity, Youden’s index and coincidence rate of the florescent RAA assay were estimated. In addition, 20 samples consisted of 5 negative specimens and 15 positive specimens with 1, 2 and 3 infected snails respectively were grouped randomly. The same specimens were detected using the crushing method and fluorescent RAA assay with the blind method in a paired?design manner. Then, the test results were compared and analyzed. Results Florescent RAA assay detected 29 positives in the 30 specimens containing different numbers of infected snails, with a sensitivity of 96.67%, and 8 negatives in the 10 detection specimens without infected snails, with a specificity of 80.00%, showing a Youden’s index of 0.77. The coincidence rate was 100% among 10 repeated assays for a detection specimen. In addition, there was no significant difference in the detection of infected snails between the florescent RAA assay and the crushing method ([χ2] = 0, P > 0.05), and the actual coincidence rates of the florescent RAA assay and crushing method were 95.00% (19/20) and 90.00% (18/20) with the real results, respectively. Conclusion Fluorescent RAA assay has a favorable efficiency for the detection of S. japonicum infections in Oncomelania snails, which shows a potential in screening of S. japonicum?infected Oncomelania snails.
    Study on the mechanism of resistance to cypermethrin in Culex pipiens pallens using proteomics
    LIU Fu-Yan, ZHANG Qian, GUO Xiu-Xia, SONG Xiao, ZHANG Chong-Xing
    2021, 33(2):  189. 
    Asbtract ( )   PDF (1128KB) ( )  
    Related Articles | Metrics
    Objective To compare the differentially expressed proteins between cypermethrin?resistant and ?sensitive Culex pipiens pallens, so as to unravel the mechanism underlying the resistance to cypermethrin in Cx. p. pallens. Methods A quantitative proteomic analysis was performed among cypermethrin?sensitive and ?resistant isolates of Cx. p. pallens using isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography with tandem mass spectrometry (LC?MS/MS). Results A total of 164 differentially expressed proteins were identified between cypermethrin?sensitive and ?resistant isolates of Cx. p. pallens, including 54 up?regulated proteins and 110 down?regulated proteins. A large number of cuticular proteins, larval cuticular proteins, pupal cuticular proteins and cuticular structural constituent proteins, which are associated with cytoskeletal structure and components, were differentially expressed between cypermethrin?sensitive and ?resistant isolates of Cx. p. pallens. Thirteen proteins, which were involved in energy production and conversion, translation, ribosomal structure and biogenesis, lipid transport and metabolism, post?translational modification, protein turnover, chaperones, cytoskeleton and intracellular transportation, were validated to be differentially expressed between cypermethrin?sensitive and ?resistant isolates of Cx. p. pallens, which may serve as potential markers of cypermethrin resistance. Conclusion Multiple insecticide resistance mechanisms contribute to the resistance to cypermethrin in Cx. p. pallens, including cuticular resistance and metabolic resistance, and the cuticular protein genes and cytochrome P450 enzymes may play an important role in the resistance of Cx. p. pallens to cypermethrin.
    Endemic situation of schistosomiasis in national surveillance sites of Zhejiang Province from 2015 to 2019
    ZHANG Jian-Feng, DU Hai-Juan, YAN Xiao-Lan, YU Li-Ling, YANG Ming-Jin, LIU Rong, GU Sheng-Feng, WEN Li-Yong
    2021, 33(2):  195. 
    Asbtract ( )   PDF (966KB) ( )  
    Related Articles | Metrics
    Objective To analyze the endemic situation of schistosomiasis in national surveillance sites of Zhejiang Province, so as to provide the scientific evidence for formulating the new schistosomiasis surveillance program and consolidating schistosomiasis elimination achievements. Methods A total of 54 to 55 national surveillance sites and 6 risk monitoring sites were assigned in historical endemic regions of Zhejiang Province from 2015 to 2019, where the Schistosoma japonicum infections in humans, livestock, snails and wild feces were monitored. All data pertaining to the surveillance results were descriptively analyzed. Results There were 34 530 person?time local residents receiving serological screening for S. japonicum infections in national surveillance sites of Zhejiang Province from 2015 to 2019, and the seroprevalance of S. japonicum infections were 0.29% to 0.68%; however, no egg?positives were detected. During the period from 2015 to 2019, there were 62 086 person?time mobile populations receiving serological screening for S. japonicum infections in national surveillance sites of Zhejiang Province, and the seroprevalance of S. japonicum infections were 0.32% to 0.56%; additionally, there were 27 egg?positives identified, including 3 imported cases with schistosomiasis haematobia and one case with acute schistosomiasis japonica, indicating that the adjusted prevalence of Schistosoma infections were 0.01% to 0.07% among mobile populations. A total of 829 livestock were examined for S. japonicum infections, with no positives detected. There were 10.55 hm2 and 2.89 hm2 snail habitats found in national surveillance sites and risk monitoring sites of Zhejiang Province during the 5?year period, respectively; however, no S. japonicum infections were identified in snails. Moreover, a total of 305 wild feces were tested for S. japonicum infections, and no egg?positives were identified. Conclusions The schistosomiasis elimination achievement have been consolidated in Zhejiang Province; however, the risk factors of re?emerging schistosomiasis have not been completely eliminated, such as residual snails and imported schistosomiasis cases. Further surveillance and control activities of snails and the source of S. japonicum infections should be reinforced.
    Longitudinal surveillance of schistosomiasis in hilly regions of Sichuan Province from 2015 to 2019
    XU Jia, XU Liang, ZHANG Yu, LI Rong-Zhi, WAN Jia-Jia, LU Ding, LIU Yang, WU Zi-Song
    2021, 33(2):  200. 
    Asbtract ( )   PDF (1163KB) ( )  
    Related Articles | Metrics
    Objective To investigate the changes in the endemic situation of schistosomiasis in national surveillance sites of Sichuan Province, so as to provide the scientific evidence for formulating the schistosomiasis elimination strategy. Methods From 2015 to 2019, 63 national schistosomiasis surveillance sites were assigned in Sichuan Province, in which Schistosoma japonicum infections were monitored in humans, livestock, wild feces and snails. The monitoring data were descriptively analyzed. Results A total of 94 119 person?time local residents were serologically screened for S. japonicum infections in 63 national surveillance sites of Sichuan Province from 2015 to 2019, with sero?prevalence rates ranging from 1.28% to 3.11%, and the sero?positives were predominantly detected in local residents at ages of over 50 years and in farmers. A total of 94 119 person?time mobile populations were serologically screened for S. japonicum infections in the national surveillance sites during the 5?year period, with sero?prevalence of 1.10% to 1.59%. There were no egg?positives identified in either local residents or mobile populations. Among the 6 126 herd?time livestock detected, no egg?positives were identified, and no S. japonicum infection was detected in the 205 wild feces. Snail survey was performed covering an area of 8 484.08 hm2, and 724.80 hm2 snail habitats were identified, including 2.43 hm2 emerging snail habitats and 63.00 hm2 re?emerging snail habitats. The mean occurrence of frames with snails was 6.87% to 19.63%, and the mean density of living snails was 0.18 to 0.62 snails/0.1 m2 in the national surveillance sites of Sichuan Province from 2015 to 2019; however, no S. japonicum infection was detected in snails. Conclusions The endemic situation of schistosomiasis has reduced to the lowest level in Sichuan Province; however, there is a rise in snail habitats, and there is still a risk of schistosomiasis resurgence. Further improvements of the surveillance system for schistosomiasis are required to achieve the goal of schistosomiasis elimination in Sichuan Province as soon as possible.
    Survey of Oncomelania hupensis in national schistosomiasis surveillance sites of Guangxi Zhuang Autonomous Region from 2015 to 2019
    TANG Wen-Qian, HUANG Keng-Lin, SHI Yun-Liang, Lü Guo-Li, ZHANG Wei-Wei, Lü Shan, LIU Jian, HUANG Wen-Jie, JIANG Zhi-Hua
    2021, 33(2):  205. 
    Asbtract ( )   PDF (1010KB) ( )  
    Related Articles | Metrics
    Objective To investigate the distribution characteristics of Oncomelania hupensis in Guangxi Zhuang Autonomous Region, so as to provide insights into the assessment of the risk of schistosomiasis transmission and the scientific formulation of the schistosomiasis surveillance strategy. Methods From 2015 to 2019, a total of 19 national schistosomiasis surveillance sites were assigned in Guangxi Zhuang Autonomous Region, including 4 fixed sites and 15 mobile sites. Snail survey was performed by means of systematic sampling in combination with environmental sampling, and the infection of Schistosoma japonicum was detected by the crushing method combined with loop?mediated isothermal amplification (LAMP) assay. Results From 2015 to 2019, snail habitats were detected at areas of 17 040 to 39 527 m2, including 6 214 m2 emerging snail habitats and 16 563 m2 re?emerging snail habitats. The overall mean density of living snails was 0.019 2 snails/0.1 m2 and the occurrence of frames with snails was 1.11% in the national schistosomiasis surveillance sites; however, no S. japonicum infection was identified in snails. The area of snail habitats increased by 121.46% in the national surveillance sites in 2019 as compared to that in 2015; however, 50.34% (Z = ?0.422, P > 0.05)and 42.85%(χ2 = 130.41, P < 0.01) reductions were seen in the overall means density of living snails and the occurrence of frames with snails. All snail habitats were distributed in the 4 fixed surveillance sites, and were mainly found in ditches, paddy fields and dry lands, with weeds as the primary vegetation type. Conclusions There are still risk factors leading to re?emergent transmission of schistosomiasis in Guangxi Zhuang Autonomous Region, such as local snail spread, and the monitoring of schistosomiasis remains to be reinforced to further consolidate the achievements of schistosomiasis elimination in the region.
    Progress of researches on the involvement of indoleamine 2, 3-dioxygenase in regulation of parasite-host immune interactions
    WANG Li-Jun, MA Pei-Yu, LIU Hui, CAO Jian-Ping, LI Hua-Mei, ZHENG Ming-Hui
    2021, 33(2):  209. 
    Asbtract ( )   PDF (936KB) ( )  
    Related Articles | Metrics
    Indoleamine 2, 3?dioxygenase (IDO) is an important immunoregulatory enzyme, which mediates immune effects by depleting tryptophan and producing multiple metabolites. Recently, the studies on the immune function of IDO have been mostly restricted in tumors and autoimmune diseases. Nevertheless, there are few studies pertaining to the role of IDO in parasitic diseases, notably in parasite?host immune interactions. This review mainly describes IDO?mediated immunoregulatory effects and its regulation of parasite?host interactions, so as to provide insights into the development of immune intervention schemes against parasitic diseases.
    Progress of researches on the development of non-benzimidazoles for the treatment of echinococcosis
    LI Song, HAN Xiu-Min, GUO Ya-Min
    2021, 33(2):  213. 
    Asbtract ( )   PDF (965KB) ( )  
    Related Articles | Metrics
    The long?term use of benzimidazoles for the treatment of echinococcosis may cause multiple adverse reactions and low compliance. A search for novel agents, as an alternative of benzimidazoles, is therefore of great significance for the treatment of echinococcosis. This review focuses on the progress of researches on non?benzimidazoles for the clinical treatment of echinococcosis, including anti?parasitic agents, anti?proliferative agents and plant extracts, so as to provide insights into the further development of non?benzimidazoles.
    Clinical characteristics, diagnosis and treatment of human babesiosis: a review
    WANG Fan, JIANG Jia-Fu, TIAN Jie, DU Chun-Hong
    2021, 33(2):  218. 
    Asbtract ( )   PDF (979KB) ( )  
    Related Articles | Metrics
    Babesiosis is an important tick?transmitted zoonosis caused by hematotropic parasites of the genus Babesia, zoonosis disease, which is widely distributed across the world. There are 12 species of Babesia causing human diseases, including B. microti, B. divergens, B. venatorum and B. duncani. The clinical symptoms of human Babesia infections mainly include fever, headache, chills, myalgia and fatigue, and severe infections may cause death. The diagnosis of babesiosis mainly depends on laboratory testing combined with clinical manifestations and epidemiological surveys, and the diagnostic techniques mainly include microscopic examinations of the blood smears, serological tests and molecular biological assays. Currently, azithromycin?atovaquone or clindamycin?quinine combinations are common treatments for babesiosis. This review summarizes the clinical features following human infections with various species of Babesia, the diagnostic techniques and diagnostic criteria of babesiosis and the currently available treatments for babesiosis.