Table of Content

12 January 2022, Volume 33 Issue 6

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Field evaluation and future applications of the world’s first malaria vaccine

GAO Qi

2021, 33(6):  551. 

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This paper describes the safety, efficacy and operability of the world’s first malaria vaccine (RTS, S/AS01) in latest field pilot studies and the recommendations from the WHO expert group for its use. In addition, further studies to examine the associations of inoculation rate and full⁃dose rate with the reduction in morbidity and mortality of malaria among target children and explore the scientific evidence for seasonable preventive vaccination with 5 doses and more among children at ages of below 5 years are recommended.

Potential challenges for large⁃scale uses of RTS, S/AS01 vaccine in malaria⁃endemic areas

FENG Gao⁃qian

2021, 33(6):  553. 

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RTS, S/AS01 vaccine has recently been recommended by the WHO for large⁃scale uses in malaria⁃endemic areas, which is a milestone in the history of the fight against parasitic infections. Nevertheless, RTS, S/AS01 vaccine is not perfect. Hereby, the shortages of RTS, S/AS01 malaria vaccine were discussed, and the potential challenges during the research and development of next⁃generation malaria vaccines were analyzed.

Prospects and reflections on the research and development of next⁃generation malaria vaccines

XIAO Bo, HUANG Zheng⁃hui, JIANG Lu⁃bin

2021, 33(6):  555. 

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Vaccination is one of the most effective intervention for the containment and elimination of infectious diseases. Recently, the world’s first malaria vaccine RTS, S/AS01 was approved by WHO for use among children living in moderately and highly malaria endemic areas of Africa, which brings a hope for the research and development of malaria vaccines. Here, we review the current status of malaria vaccines development and provide a perspective on the development of next⁃generation malaria vaccines, so as to provide insights into the successful development of malaria vaccines.

Development and application of the world’s first malaria subunit vaccine RTS, S/AS01

XU Wen⁃yue

2021, 33(6):  557. 

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On October, 2021, the WHO announced the recommendation of RTS, S/AS01 for use among children living in moderately and highly malaria⁃endemic areas, which receives global attention. Here, the history of RTS, S/AS01 vaccine development and its role in malaria control are described.

he world’s first malaria vaccine: Hope and challenge

ZHANG Yi⁃long, PAN Wei⁃qing

2021, 33(6):  560. 

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The RTS,S/AS01 is a subunit malaria vaccine against the pre-erythrocytic stage of Plasmodium falciparum. After over 30 years of research and development and clinical trials, this vaccine has been recommended by the WHO for use among children living in highly malaria endemic areas. Although the RTS, S/AS01 vaccine suffers from problems of a low protective efficacy (about 30%), need of four doses and short duration of protective immunity, this malaria vaccine is expected to save tens of thousands of children’s lives, and avoid tens of millions of malaria cases annually, because there have been tens of thousands of childhood deaths due to malaria recently. The introduction of the RTS, S/AS01 vaccine is therefore, widely accepted as a milestone in the history of battle against malaria, which brings a hope to contain malaria and even eventually eliminate malaria. Although there are still multiple challenges in the development of a satisfactory malaria vaccine, the success of the RTS, S/AS01 malaria greatly facilitates the progress towards the development of parasitic disease vaccines, and a more perfect malaria vaccine deserves expectations.

Current status and challenges for taeniasis and cysticercosis control in China

GUO Zhao⁃yu, LIU Jian⁃feng, ZHOU Chang⁃hai, QIAN Men⁃bao, CHEN Ying⁃dan, ZHOU Xiao⁃nong, LI Shi⁃zhu

2021, 33(6):  563. 

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In the WHO new road map for neglected tropical diseases 2021—2030, the disease⁃specific targets are classified into control, elimination as a public health problem, elimination and eradication, and taeniasis and cysticercosis are targeted for control. The overall prevalence of taeniasis and cysticercosis is low in China, and varies remarkably in regions and populations; however, there are many challenges for elimination of taeniasis and cysticercosis in China. Based on previous taeniasis and cysticercosis control programs, developing a sensitive taeniasis and cysticercosis surveillance⁃response system, updating criteria for diagnosis of taeniasis and cysticercosis, proposing a national guideline for treatment of taeniasis and cysticercosis, and strengthening interdisciplinary and intersectoral communications and collaborations are urgently needed under the One Health concept.

Emergency responses to schistosomiasis outbreak during the stage moving towards elimination in China

CHEN Lin, CAO Chun⁃li, LIU Yang, ZHONG Bo

2021, 33(6):  570. 

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Currently, the national schistosomiasis control program of China is moving from transmission control and transmission interruption to elimination; however, there is still a threat of schistosomiasis outbreak in area where the transmission of schistosomiasis has not been interrupted, and in areas where transmission interruption and even elimination have been achieved because of the complex factors relating to schistosomiasis transmission, as well as socioeconomic factors and natural environments, which greatly affects the consolidation of schistosomiasis control outcomes and the achievement of the goal of schistosomiasis elimination in the country. Here, we summarized the outbreaks of schistosomiasis in China during the past six decades, evaluated the impact of schistosomiasis outbreak on the national schistosomiasis control program and proposed management of schistosomiasis outbreak and prevention of schistosomiasis resurgence as the key point and difficulty for schistosomiasis control in the current stage. Improving the surveillance⁃response mechanisms and minimizing the development of schistosomiasis outbreak and the resultant damages and losses are recommended to provide technical supports for elimination of schistosomiasis in China.

Role of inducible costimulatory molecules (ICOS) and related cytokines in immune regulation of Echinococcus granulosus infections in mice

YANG Chen⁃chen, ZHANG Ji⁃xiu, WEI Qin, JIANG Tao

2021, 33(6):  575. 

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Objective　To investigate the roles of inducible costimulatory molecules (ICOS) and related cytokines in the immune regulation of Echinococcus granulosus infections in mice. Methods　Eighty BALB/c mice (weight 18-22 g) were divided into the control and infection groups, of 40 animals in each group. E. granulosus infection was modeled in mice by intraperitoneal injection of 10 000 protoscoleces per mouse. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) and peripheral interleukin⁃4 (IL⁃4) and IL⁃10 levels were measured 2, 8, 30, 60, 180 days post⁃infection. Mouse liver specimens were excised for hematoxylin⁃eosin (HE) staining and immunostaining, and ICOS expression was quantified in mouse liver specimens using quantitative real⁃time PCR (qPCR) assay. Results　There were no significant differences in serum ALT (F = 12.082, P < 0.05), AST (F = 6.347, P < 0.05) or ALP levels (F = 52.186, P < 0.05) in mice 2, 8, 30, 60 and 180 days post⁃infection with E. granulosus. The serum ALT levels were significantly higher in the infection group than in the control group 2 [(61.72 ± 9.89) vs. (50.65 ± 4.67) U/L, P < 0.05] and 30 days post⁃infection [(80.61 ± 23.71) vs. (67.75 ± 9.79) U/L, P < 0.05], and the serum ALT levels were significantly higher in the infection group than in the control group 2 [(181.06 ± 60.61) vs. (115.58 ± 17.66) U/L, P < 0.05] and 180 days post⁃infection [(137.84 ± 29.01) vs. (108.05 ± 10.33) U/L, P < 0.05], while greater serum ALP levels were measured in the infection group than in the control group 2 [(162.90 ± 21.04) vs. (64.54 ± 5.99) U/L, P < 0.05], 8 [(176.36 ± 24.56) vs. (62.70 ± 9.21) U/L, P < 0.05] and 30 days post⁃infection [(138.86 ± 13.59) vs. (58.60 ± 5.28) U/L, P < 0.05]. A few inflammatory cells were seen in mouse liver in the infection group 30 days post⁃infection, and no apparent changes were found in the mouse hepatic structure 60 days post⁃infection. On day 180 post⁃infection, a large number of epithelium⁃like cells presented fibrotic growth in mouse liver in the cyst⁃infiltrating regions, with cuticula formation seen, and plenty of red cells were present in lesions and hepatocyte space. Positive ICOS expression was detected in mouse liver in the infection group, with ICOS⁃positive cells predominantly seen in the cytoplasm of the hepatocyte, and the ICOS expression increased over time. The relative ICOS mRNA expression was 2.732 ± 0.094 on day 180 post⁃infection, which was significantly greater than that on day 2 post⁃infection (0.746 ± 0.049). There were no significant differences in serum IL⁃4 or IL⁃10 levels at different time points after E. granulosus infections, while the serum IL⁃4 and IL⁃10 levels peaked in the infection group180 days and 60 days post⁃infection, respectively. Higher serum IL⁃4 levels were measured in the infection group than in the control group 8 [(22.50 ± 3.24) vs. (5.82 ± 0.49) pg/mL, P < 0.05], 30 [(15.49 ± 4.73) vs. (5.10 ± 1.38) pg/mL, P < 0.05], 60 [(36.93 ± 6.14) vs. (4.13 ± 1.19) pg/mL, P < 0.05] and 180 days post⁃infection [(198.35 ± 0.70) vs. (4.19 ± 0.98) pg/mL, P < 0.05], and higher IL⁃10 levels were measured in the infection group than in the control group 2 [(4.84 ± 1.91) vs. (2.11 ± 1.03) pg/mL, P < 0.05], 8 [(44.72 ± 14.63) vs. (3.16 ± 0.60) pg/mL, P < 0.05], 30 [(25.47 ± 8.00) vs. (3.83 ± 1.87) pg/mL, P < 0.05], 60 [(187.16 ± 60.44) vs. (3.69 ± 1.05) pg/mL, P < 0.05] and 180 days post⁃infection [(85.40 ± 7.15) vs. (3.25 ± 0.93) pg/mL, P < 0.05]. Conclusions　High ICOS expression is present in the liver of mice with E. granulosus infections. The positive ICOS expression and immune activation levels increase with the time of E. granulosus infections, leading to aggravation of hepatocyte injury caused by inflammation.

Effectiveness of health education interventions targeting taeniasis and cysticercosis among primary school students in disease⁃elimination pilot areas of Henan Province

DENG Yan, JIANG Tian⁃tian, JI Peng⁃hui, CHEN Wei⁃qi, ZHANG Ya⁃lan, HONG Yang, ZHOU Rui⁃min, YANG Cheng⁃yun, HU Ya⁃bo, LIN Xi⁃meng, ZHAO Dong⁃yang

2021, 33(6):  583. 

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Objective　To compare the changes of knowledge, attitude and practice (KAP) related to taeniasis and cysticercosis among primary school students before and after health education interventions in disease⁃elimination pilot areas of Henan Province, so as to evaluate the effectiveness of health education interventions. Methods　A primary school was selected from each of Dushu, Bowang and Yangji townships, Fangcheng County, Henan Province from 2017 to 2019; then, 2 to 3 classes were randomly selected from grade 4 to 6 in each primary school, and finally, all students in these classes were enrolled as study subjects. A thematic health education lecture pertaining to taeniasis and cysticercosis was given once each year by means of “health education in class”. The KAP towards taeniasis and cysticercosis was investigated among primary school students using self⁃filled structured questionnaires, and the changes of awareness of taeniasis and cysticercosis control knowledge and percentage of healthy behaviors formation were compared in primary school students among years and following various frequencies of health education interventions. Results　More than 10 thousand person⁃time primary school students received health education interventions during the period from 2017 to 2019, and a total of 1 223 person⁃time primary school students were investigated during the 3⁃year study period, including 633 person⁃time men and 590 person⁃time women and 88.55% of primary school students at ages of 10 to 12 years. The proportion of households raising pigs and using dry toiliets decreased from 5.30% (24/453) and 18.10% (82/453) in 2017 to 3.60% (13/361) and 11.08% (40/361) in 2019, respectively. The awareness rate of taeniasis and cysticercosis control knowledge increased significantly from 0.22% (1/453) in 2017 to 62.59% (256/409) in 2018 and 76.73% (277/361) in 2019 ([χ2] = 567.60, P < 0.001), and the awareness rate was 85.25% (104/122) among primary school students attending the thematic special health education courses for successive three times. The awareness rates of taeniasis and cysticercosis control knowledge were 0.44% (1/225), 58.00% (116/200) and 71.63% (149/208) among male students and 0 (0/338), 66.99% (140/209) and 83.66% (128/153) among female students from 2017 to 2019, and there was a significant difference in the awareness of taeniasis and cysticercosis control knowledge between male and female students in 2019 ([χ2] = 7.14, P = 0.01). On⁃site teaching by doctors was the students’ favorite way to receive health education interventions (70.07%, 857/1 223), followed by watching health education videos (58.63%, 717/1 223) and seeing parasite specimens (48.9%, 598/1 223). The proportion of students’ families who used cutting boards for raw and cooked food separately increased from 7.28% (33/453) in 2017 to 47.37% (171/361) in 2019, was 67.21% (82/122) among students attending the health education courses for successive three times. The proportion of students who frequently washed their hands before meals and after using toilet increased from 71.96% (324/453) in 2017 to 89.47% (319/361) in 2019 and was 95.90% (117/122) among students attending the health education courses for successive three times. In addition, the percentage of students washing hands frequently in families using dry toilets was significantly lower in those who did not use dry toilets ([χ2] = 9.21, P = 0.002), and the proportion of students with a habit of eating raw or undercooked meat decreased significantly from 35.76% (162/453) in 2017 to 6.65% (24/361) in 2019 ([χ2] = 69.11, P < 0.01). Conclusion　The thematic health education activity of “health education in class” contributes greatly to the increase in the awareness of taeniasis and cysticercosis control knowledge and the rate of healthy behaviors formation among primary school students in disease⁃elimination pilot areas of Henan Province.

Investigation on freshwater crab populations and Paragonimus infections in the Minjiang River basin along the middle section of Wuyi Mountain

CHEN Ji⁃qing, LIU Shi⁃han, LUO Jun, CAI Mao⁃rong, CHENG You⁃zhu

2021, 33(6):  590. 

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Objective　To investigate the populations of freshwater crabs, the intermediate host of Paragonimus and Paragonimus infections in freshwater crabs in the Minjiang River basin along the middle section of Wuyi Mountain, so as to provide baseline data for parasitic disease control and research and expansion of the parasite resource bank. Methods　From November 2020 to April 2021, freshwater crabs were sampled from streams and ditches neighboring residential areas in Jianning County and its neighboring Ninghua, Shaowu, Jiangle and Shunchang counties. The crab species was identified based on the morphological features of the terminal segment of the first abdominal appendage of male crabs, and Paragonimus infections were detected in freshwater crabs. The Paragonimus metacercariae were isolated, and the types of metacercariae were identified based on the metacercaria size, cystic wall thickness, and the excretory bladder and intestinal tract morphology. In addition, the prevalence, intensity and index of metacercaria infections were calculated in freshwater crabs. Results　There were seven crab species found in Jianning County and six neighboring water systems along the Minjiang River basin, including Sinopotamon jianglense, S. fukinense, Huananpotamon lichuanense, H. lini, H. shenni, H. planopodum, Bottapotamon engelhardti, and there were metacercariae of three Paragonimus species detected in these crabs, including P. westermani, P. skrjabini and P. sanpingensis, with a prevalence rate of 43.6% (125/287). The infection rates of P. westermani, P. sanpingensis and P. skrjabini were 57.1% (48/84), 26.2% (22/84) and 61.8% (21/34) in S. jianglense, and the infection rates of P. westermani and P. sanpingensis were 52.6% (51/97) and 30.9% (30/97) in S. fukinense, while the rate of P. westermani infection was 6.9% (5/72) in H. lichuanense, which is the first record of P. westermani infections in H. lichuanense. Mixed P. westermani and P. sanpingensis infections were predominantly found in freshwater crabs sampled from Jianning County, where the rate of Paragonimus infections was 70.4% (76/108), with 15.3 metacercariae identified in each crab with Paragonimus infections and 1.9 metacercariae found in each gram of crabs with Paragonimus infections, and the index of metacercariae infections was 20.5. In addition, P. westermani, P. skrjabini and P. sanpingensi metacercariae were found in freshwater crabs sampled from Jianning⁃neighboring counties, where the rate of Paragonimus infections was 52.3% (56/107), with 9.8 metacercariae identified in each crab with Paragonimus infections and 0.9 metacercariae found in each gram of crabs with Paragonimus infections, and the index of metacercariae infections was 4.6. Conclusion　There are multiple freshwater crab species and Paragonimus infection is high in freshwater crabs in Jianning County and its neighboring Minjiang River basin, which is a high⁃risk natural focus for Paragonimus infections.

Effectiveness of training on Taenia solium taeniasis and cysticercosis control knowledge among medical professionals in disease⁃elimination pilot areas of Henan Province

CHEN Wei⁃qi, JIANG Tian⁃tian, DENG Yan, ZHANG Ya⁃lan, CHEN Xi, HONG Yang, ZHAO Dong⁃yang, LIN Xi⁃meng, ZHANG Hong⁃wei

2021, 33(6):  600. 

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Objective　To investigate the changes in the awareness rate of Taenia solium taeniasis and cysticercosis control knowledge among medical professionals before and after training in Fangcheng County, a disease⁃elimination pilot area of Henan Province, so as to evaluate the effectiveness of the training. Methods　Three townships in Fangcheng County were randomly selected as the study townships, including Dushu, Bowang and Yangji townships, while Erlangmiao, Yanglou and Xiaoshidian townships in the county were randomly selected as the control townships. The grassroots medical professionals in the study townships were given once training on T. solium taeniasis and cysticercosis control knowledge each year from 2016 to 2020, while those in the control townships were given no interventions. All village⁃level doctors and a part of township⁃level public health professionals were sampled from the study and control townships as intervention and control groups. The baseline and final assessments of the awareness of T. solium taeniasis and cysticercosis control knowledge were performed using questionnaire survey in intervention and control groups in 2016 and 2020, and the awareness of T. solium taeniasis and cysticercosis control knowledge was compared between the two groups. Results A total of 663 medical professionals were investigated in Fangcheng County from 2016 to 2020, including 474 participants in the intervention group and 189 participants in the control group. Results from the 2016 baseline survey showed that the awareness rate of T. solium taeniasis and cysticercosis control knowledge was 28.83% (47/163) among grassroots medical professionals in Fangcheng County, and there were no significant differences in the awareness between the intervention (32.47%, 25/77) and control groups (25.58%, 22/86) ([χ2] = 0.939, P > 0.05), between men (30.50%, 43/141) and women (18.18%, 4/22) ([χ2] = 1.406, P > 0.05) or between village⁃ (31.39%, 43/137) and township⁃level medical professionals (15.38%, 4/26) ([χ2] = 2.727, P > 0.05), while significant differences were found in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of education levels ([χ2] = 8.190, P < 0.05) and duration of working experiences ([χ2] = 12.617, P < 0.05), and the awareness rate of T. solium taeniasis and cysticercosis control knowledge increased with education levels among medical professionals ([χ2] = 6.768, P < 0.05). Only 5.52% (9/163) of the medical professionals had a history of diagnosis and therapy of T. solium taeniasis or cysticercosis, and only 1.23% (2/163) received training on T. solium taeniasis and cysticercosis control knowledge during the past 5 years. Results from the 2020 questionnaire survey showed a higher awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in the intervention group (93.55%, 116/124) than in the control group (46.60%, 48/103) ( [χ2] = 61.845, P < 0.05), and no significant differences were seen in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of gender, level of medical professionals, duration of working experiences or history of diagnosis/therapy of T. solium taeniasis and cysticercosis in the intervention group ([χ2] = 1.089, 0.140, 0.081 and 0.453, all P values > 0.05), while there was a significant difference in the awareness rate among medical professionals with different education levels ([χ2] = 36.338, P < 0.05). In addition, the awareness rate of T. solium taeniasis and cysticercosis control knowledge significantly increased among medical professionals with various chracteristics in 2020 than in 2016. Conclusions　In the low⁃prevalence areas of T. solium taeniasis and cysticercosis, long⁃term and persistent training may improve the awareness of T. solium taeniasis and cysticercosis control knowledge among grassroots medical professionals, which facilitates the timely identification of T. solium taeniasis and cysticercosis and the establishment of a sensitive disease surveillance system.

Epidemiological characteristics of imported malaria in Zhengzhou City from 2016 to 2020

GAO Li⁃hua, SHI Jia⁃jia, ZHANG Yue⁃quan, LÜ Ming⁃jie, ZHAO Xue⁃lei, LIU Ying, WANG Xiao, YUAN Zhong⁃liang

2021, 33(6):  606. 

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Objective　To analyze the epidemiological characteristics of reported imported malaria cases in Zhengzhou City from 2016 to 2020, so as to provide insights into the management of imported malaria in the city. Methods　All data pertaining to cases with definitive diagnosis of malaria in Zhengzhou City from 2016 to 2020 were captured from the National Notifiable Disease Report System and the Information Management System for Parasitic Disease Control in China, including individual demographic data, and malaria onset, initial diagnosis and definitive diagnosis data. All data were descriptively analyzed. The duration from malaria onset to initial diagnosis, from initial diagnosis to definitive diagnosis and from onset to definitive diagnosis was compared among cases. In addition, the diagnoses of imported malaria cases in which definitive diagnosis was made were compared with the reexaminations by Zhengzhou Municipal Malaria Diagnosis Reference Laboratory. Results　A total of 302 cases with definitive diagnosis of malaria were reported in Zhengzhou City from 2016 to 2020, and all were imported cases, with Plasmodium falciparum malaria as the predominant type (230 cases, 76.2%). There were 293 malaria cases imported from Africa (293 cases, 97.0%), which mainly included Nigeria (48 cases, 15.9%), Angola (40 cases, 13.2%), and the Democratic Republic of the Congo (29 cases, 9.6%). There was no obvious seasonality found in the date of malaria onset and time of reporting malaria. The ratio of male to female malaria cases was 49.3∶1, and there were 103 cases (34.1%) with the current residency address in Zhengzhou City, 193 cases (63.9%) with the current residency address in other cities of Henan Province and 6 cases (2.0%) in other provinces of China. There were 271 cases (89.7%) seeking initial diagnosis in medical institutions, and the diagnostic accuracy of malaria was 56.6% (171/302) at initial diagnosis institutions. A total of 122 cases (40.4%) sought medical care on the day of malaria onset, and 252 cases (86.4%) within 3 days; however, only 22 cases (7.3%) were definitively diagnosed on the day of onset, and 162 cases (53.6%) diagnosed within 3 days. There were no significant differences between malaria cases seeking initial diagnosis at medical institutions and disease control and prevention institutions in terms of the duration from malaria onset to initial diagnosis (Z = −1.663, P > 0.05), from initial diagnosis to definitive diagnosis (Z = −0.413, P > 0.05) or from malaria onset to definitive diagnosis (Z = −0.838, P > 0.05). The median duration (interquartile range) from initial diagnosis to definitive diagnosis of malaria was 3.00 (2.00), 3.00 (6.00), 2.00 (4.00) d and 1.00 (1.00) d among cases seeking medical care at township⁃level and lower, county⁃, city⁃ and province⁃level medical institutions, and the median duration from initial diagnosis to definitive diagnosis of malaria was significantly longer among cases seeking medical care at township⁃level and lower medical institutions than at city⁃ (Z = −3.286, P < 0.008 33) and province⁃level medical institutions (Z = −9.119, P < 0.008 33), while the median duration from initial diagnosis to definitive diagnosis [1.00 (3.00) d vs. 2.00 (4.00) d; Z = −4.099, P < 0.016] and from malaria onset to definitive diagnosis [3.00 (4.00) d vs. 4.00 (5.00) d; Z = −2.868, P < 0.016] among malaria cases with the current residency address in Zhengzhou City was both shorter than in other cities of Henan Province. The diagnostic accuracy was 89.1% (269/302) among malaria cases in which definitive diagnosis was made, and the accuracy of malaria reexaminations was 94.0% (284/302) in Zhengzhou Municipal Malaria Diagnosis Reference Laboratory. Conclusions　P. falciparum malaria was predominant among reported imported malaria cases in Zhengzhou City from 2016 to 2020, and these imported malaria cases were predominantly diagnosed at medical institutions; however, the diagnostic capability of malaria is poor in township⁃level and lower medical institutions. Strengthening the collaboration between medical institutions and disease control and prevention institutions and improving the diagnostic capability building at medical institutions are recommended to consolidate malaria elimination achivements.

Expression of hypoxia⁃inducible factor⁃1 in mice infected with Toxoplasma gondii during pregnancy

ZENG Yu⁃lu, XUE Sa, BI Xiang⁃lian, YAN Ling⁃xin, YANG Jun, ZHANG Da⁃yi, GOU Yong⁃song, FU Xiao⁃yin, LIU Deng⁃yu

2021, 33(6):  615. 

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Objective　To investigate the expression and possible role of hypoxia⁃inducible factor⁃1 (HIF⁃1) at the maternal⁃fetal interface following Toxoplasma gondii infection during early pregnancy. Methods　Twenty pregnant C57BL/6 mice, each weighing 16 to 20 g, were randomly divided into 4 groups, including the 12⁃d control group, 12⁃d infection group, 18⁃d control group and 18⁃d infection group. Mice in the 12⁃d and 18⁃d infection groups were injected intraperitoneally with 150 tachyzoites of the T. gondii PRU strain on day 6 of pregnancy, while mice in the 12⁃d control and 18⁃d control groups were injected with the same volume of phosphate buffered saline (PBS). Mice in the control and infection groups were sacrificed on days 12 and 18 of pregnancy, and the placental and uterine specimens of the pregnant mice in each group were sampled for pathological examinations. The mRNA expression of HIF⁃1α, HIF⁃1β and vascular endothelial growth factor (VEGF) was quantified using quantitative fluorescent real⁃time PCR (qPCR) assay in the placental and uterine specimens, and the correlation between HIF⁃1α and VEGF mRNA expression was examined. In addition, and the HIF⁃1α expression was detected using immunohistochemical staining in the placental and uterine specimens of pregnant mice. Results　Compared with the 12⁃d and 18⁃d control groups, adverse pregnant outcomes were observed in mice in 12⁃d and 18⁃d infection groups, such as teratism and placental dysplasia. HE staining showed swelling and blood stasis of cells, sinusoid reduction and inflammatory cell infiltration in the labyrinth area of the placenta specimens of mice in 12⁃d and 18⁃d infection groups relative to 12⁃d and 18⁃d control groups, and columnar epithelial cell injury and inflammatory cell infiltration were seen in the mouse uterine specimens in both infection groups. qPCR assay detected significantly higher HIF⁃1α (F = 132.6, P < 0.05) and HIF⁃1β mRNA expression (F = 286.9, P < 0.05) in the placental specimens and lower HIF⁃1α (F = 111.5, P < 0.05) and HIF⁃1β mRNA expression (F = 55.2, P < 0.05) in the uterine specimens in the 12⁃d infection group than in the 12⁃day control group, and significantly lower HIF⁃1α and HIF⁃1β mRNA expression was detected in the placental and uterine specimens in the 18⁃d infection group than in the 18⁃day control group (F = 215.8, 418.9, 156.8 and 200.1; all P values < 0.05). Significantly lower VEGF⁃A (F = 426.2, P < 0.05), VEGF⁃B (F = 104.6, P < 0.05) and VEGF⁃C mRNA expression (F = 566.9, P < 0.05) in the placental specimens and higher VEGF⁃A (F = 426.2, P < 0.05), VEGF⁃B (F = 104.6, P < 0.05) and VEGF⁃C mRNA expression (F = 566.9, P < 0.05) in the uterine specimens were detected in the 12⁃d infection group than in the 12⁃d control group, and higher VEGF⁃A, VEGF⁃B and VEGF⁃C mRNA expression was found in the placental and uterine specimens in the 18⁃d infection group than in the 18⁃d control group (F = 521.9, 100.6, 275.9, 224.6, 108.2 and 333.4; all P values < 0.05). Immunohistochemical staining showed strongly and mildly positive HIF⁃1α expression in the mouse placental labyrinth area in the 12⁃d and 18⁃d infection groups relative to 12⁃d and 18⁃d control groups, while no HIF⁃1α expression was detected in mouse uterine specimens. Conclusions　HIF⁃1α expression appears a tendency towards a rise in the second trimester and a reduction in the third trimester in mice following T. gondii infection during early pregnancy, which is contrary to the changing tendency of VEGF⁃A, VEGF⁃B, and VEGF⁃C expression. It is hypothesized that HIF⁃1α inhibits placental angiogenesis in mice during pregnancy through suppressing VEGF expression, resulting in adverse pregnant outcomes. 　

Epidemiology of echinococcosis in Serthar County of Sichuan Province in 2019

YU Wen⁃jie, WANG Qian, YANG Yi, YANG Liu, HUANG Yan, DANBA Ze⁃li, ZHONG Bo

2021, 33(6):  623. 

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Objective　To investigate the epidemiology of echinococcosis in Serthar County, Sichuan Province, so as to provide insights into optimization of echinococcosis control measures. Methods　The prevalence of human echinococcosis was surveyed among permanent residents living in Serthar County at ages of over 2 years from 2016 to 2019, and the prevalence of Echinococcus infections was surveyed in owned dogs, yaks and rodents in 2019. The epidemiological features of echinococcosis in humans and animals were descriptively analyzed. Results　The overall prevalence of human echinococcosis was 3.72% (1 613/43 362) in Serthar County from 2016 to 2019, and the prevalence rates of cystic echinococcosis, alveolar echinococcosis and mixed infections of cystic echinococcosis and alveolar echinococcosis were 1.72% (745/43 362), 1.98% (860/43 362) and 0.02% (8/43 362), respectively. The prevalence of human echinococcosis was higher in pastoral areas (4.13%, 1 577/38 149) than in semi⁃agricultural and semi⁃pastoral areas (0.69%, 36/5 213) ([χ2] = 151.82, P < 0.05); however, there was no significant difference in the prevalence between men (3.76%, 819/21 787) and women (3.68%, 794/21 575) ([χ2] = 0.19, P > 0.05). Cystic echinococcosis was the predominant type in students with echinococcosis (93.78%, 422/450), while alveolar echinococcosis was the predominant type in herders with echinococcosis (72.16%, 801/1 110). There was a significant difference in the constituent ratio of echinococcosis types between students and herders ([χ2] = 588.57, P < 0.05). In addition, higher prevalence of echinococcosis was detected in nomadic populations (4.58%, 1 008/22 021) than in community⁃dwelling populations (2.83%, 605/21 341) ([χ2] = 91.88, P < 0.05). The Echinococcus copro⁃antigen⁃positive rate was 0.19% (4/2 157) in owned dogs, and the detection rate of echinococcosis was 8.00% (16/200) in yaks and 3.10% (31/1 000) in rodents in 2019. Conclusions　Echinococcosis is highly prevalent in Serthar County, Sichuan Province. Sustained management of source of Echinococcus infections, improved treatment of echinococcosis patients and timely health education for nomadic populations are recommended.

Epidemiological features and diagnosis of malaria cases in Nantong City from 2015 to 2020

CAO Cai⁃qun, DING Gui⁃sheng

2021, 33(6):  626. 

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Objective　To investigate the epidemiological characteristics and diagnosis of malaria cases in Nantong City from 2015 to 2020, so as to provide insights into the prevention of re⁃establishment of imported malaria and consolidation of malaria elimination achievements in the city. Methods　The epidemic data of malaria in Nantong City from 2015 to 2020 were captured from the National Notifiable Disease Report System, the Information Management System for Parasitic Disease Control and individual epidemiological survey reports of malaria cases. The malaria parasite species, source of infections, population distribution, temporal distribution, spatial distribution and diagnosis of imported malaria cases were descriptively and statistically analyzed. Results　A total of 241 malaria cases were reported in Nantong City from 2015 to 2020, and all were overseas imported cases, including 191 cases with Plasmodium falciparum malaria (79.25%), 8 cases with P. vivax malaria (3.32%), 33 cases with P. ovale malaria (13.69%) and 9 cases with P. malaria malaria (3.73%). Overseas imported malaria cases acquired infections from 34 countries in Asia, Africa and Latin America, and 97.93% of the cases were infected in Africa, and 90.04% (217/241) were reported in Chongchuan District, Hai’an City and Haimen District. Imported malaria cases were aged from 20 to 68 years, and a median age of 45 (13) years, and 97.10% were male. The median duration between returning to China and malaria onset was 7 (9) days among all imported malaria cases, and the median duration from initial diagnosis to definitive diagnosis was 2 (2) days. There were 167 cases that were initially diagnosed as malaria, with a correct rate of 69.29%, and 53.53 (129/241) of malaria cases were diagnosed at city⁃level medical institutions and 41.49% (100/241) at county⁃level medical institutions. In addition, the proportion of malaria cases reported by city⁃level medical institutions increased from 39.62% in 2015 to 81.25% in 2020 ([χ2] = 6.94，P < 0.01). Conclusions　The accuracy of initial malaria diagnosis requires to be improved in Nantong City. Malaria control knowledge should be specially given to migrant workers to shorten the duration of seeking medical care, and malaria training requires to be intensified among healthcare professionals to improve the diagnostic capability of imported malaria cases and the cure of severe P. falciparum malaria cases.

Effectiveness of FibroTouch combined with four hepatic fibrosis biomarkers for evaluation of the liver fibrosis degree among patients with chronic schistosomiasis⁃induced liver disorders

HONG Ye, NIU Xue⁃hua, SHEN Yu⁃zhou, ZHOU Lei, HUANG Li⁃ping

2021, 33(6):  629. 

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Objective　To evaluate the performance of FibroTouch in combination with four hepatic fibrosis biomarkers for assessment of the degree of hepatic fibrosis among patients with chronic schistosomiasis⁃induced liver disorders. Methods　A total of 63 patients with chronic schistosomiasis⁃induced liver diseases admitted to The Third People’s Hospital of Kunshan City from January to March 2021 were enrolled as the observation group, while 50 healthy volunteers receiving health examinations in the hospital during the study period were randomly selected as the control group. The liver stiffness measurement (LSM) was determined using the FibroTouch technique, and the serum levels of four hepatic fibrosis biomarkers were detected using chemiluminescence immunoassay, including type Ⅳ collagen (Ⅳ⁃C), type Ⅲ procollagen (PC⁃Ⅲ), hyaluronidase (HA) and laminin (LN). The receiver operating characteristic (ROC) curves of LSM and four hepatic fibrosis biomarkers alone and in combination for assessing the degree of hepatic fibrosis among patients with chronic schistosomiasis⁃induced liver disorders were plotted and the area under the ROC curve (AUC) was estimated to examine the value of LSM and four hepatic fibrosis biomarkers alone and in combination for assessing the degree of hepatic fibrosis. Results　There were 63 subjects in the observation group, including 28 men and 35 women, and the participants had a mean age of (65.34 ± 12.56) years and a mean body mass index (BMI) of (24.47 ± 11.05) kg/m2. There were 50 subjects in the control group, including 22 men and 28 women, and the participants had a mean age of (64.28 ± 13.10) years and a mean BMI of (25.12 ± 11.64) kg/m2. There were no significant differences between the observation and control groups in terms of gender ratio ([χ2] = 0.002, P > 0.05), age (t = 0.437, P > 0.05) or BMI (t = 0.303, P > 0.05). The LSM [(8.65 ± 5.22) vs. (3.24 ± 1.10) kPa; t = 8.013, P < 0.05], Ⅳ⁃C [(51.80 ± 9.45) vs. (30.10 ± 10.34) ng/L; t = 11.506, P < 0.05], PC⁃Ⅲ [(77.28 ± 17.22) vs. (48.62 ± 9.54) ng/L; t = 11.224, P < 0.05], HA [(39.55 ± 5.32) vs. (84.89 ± 10.34) ng/L; t = 30.158, P < 0.05] and LN [(99.47 ± 7.37) vs. (61.93 ± 9.80) ng/L; t = 22.496, P < 0.05] were significantly greater in the observation group than in the control group, and Spearman correlation analysis showed that the degree of liver fibrosis positively correlated with LSM (rs = 0.675, P < 0.01), Ⅳ⁃C (rs = 0.421, P < 0.01), PC⁃Ⅲ (rs = 0.517, P < 0.01), HA (rs = 0.550, P < 0.01) and LN (rs = 0.539, P < 0.01) among patients with chronic schistosomiasis⁃induced liver diseases. ROC curve analysis revealed that the AUC of LSM for assessment of the hepatic fibrosis degree was 0.884 (P < 0.001), and the LSM cutoff, sensitivity and specificity were 11.75 kPa, 71.43% and 84.00% at the highest Youden index, respectively. In addition, the AUC of four hepatic fibrosis biomarkers for assessment of the hepatic fibrosis degree was 0.577 to 0.670, with 70.174 to 115.237 ng/L cutoff values, 17.46% to 68.25% sensitivity and 71.01% to 96.00% specificity. In addition, the sensitivity and specificity of LSM combined with four hepatic fibrosis biomarkers were 92.06% and 95.07% for assessment of the hepatic fibrosis degree among patients with chronic schistosomiasis⁃induced liver diseases. Conclusion　FibroTouch in combination with detection of four hepatic fibrosis biomarkers has a high sensitivity and specificity for assessing the degree of hepatic fibrosis among patients with chronic schistosomiasis⁃induced liver diseases, which deserves widespread clinical uses.

Investigation on awareness of schistosomiasis control knowledge among residents going to Africa in Taizhou City

CHEN Jian⁃feng, YANG Kun, LI Wei, ZHANG Jian⁃feng, HE Jian, HUANG Wen⁃ming

2021, 33(6):  634. 

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Objective　To understand the awareness of schistosomiasis control knowledge among people going to Africa in Taizhou City, to provide insights into the development of control measures for imported schistosomiasis. Methods　During the period from July to October, 2019, a face⁃to⁃face questionnaire survey was conducted among people that had gone to African countries between 2015 and 2018 and return to China now, including awareness of schistosomiasis control knowledge, type of living and drinking water and contact with river and lake water. Results　A total of 573 peoples going to Africa were investigated, and 572 eligible questionnaires were recovered. Among the 572 people interviewed, senior high school and above was the predominant education level (509 people, 89.0%), labor was the predominant aim (543 people, 94.9%), and Angola (52.3%) and Algeria (15.9%) were predominant destiny countries. There were 7.2% of the interviewees hearing about African schistosomiasis, 19.8% knowing infections by contact with infested water, and 36 people with a history of contact with river and lake water. In addition, 270 interviewees used running water as drinking water and 276 used running water as living water. Conclusions　The awareness rate of schistosomiasis control knowledge is low among people going to Africa in Taizhou City. Health education pertaining to schistosomiasis control is required to be improved among those going to Africa in Taizhou City to increase the awareness of schistosomiasis prevention and avoid parasitic infections.

Prevalence of Spirometra mansoni infections in hosts in Jiangsu Province

TONG De⁃sheng, TANG Xian⁃shi, ZHANG Ying, HOU Ru, ZANG Cheng⁃zhong, GUAN Xue⁃jun, XU Xing⁃yang, LIANG You⁃sheng

2021, 33(6):  636. 

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Objective　To investigate the prevalence of Spirometra mansoni infections in hosts in Jiangsu Province, so as to provide the scientific basis for the management of sparganosis mansoni. Methods　From 2018 to 2019, nine counties (cities, districts) were randomly selected from Jiangsu Province as the survey sites, and 100 healthy individuals were randomly selected to perform the serological test of S. mansoni infections and the detection of S. mansoni eggs. The procercoids were detected in the intermediate host Cyclops, and the S. mansoni eggs were identified in the stool samples of the definitive hosts cats and dogs. Results　The prevalence of S. mansoni human infections was 0 (0/900) in the 9 survey sites of Jiangsu Province, and the sero⁃prevalence of the specific IgG antibody against S. mansoni was 1.22% (11/900). The positive rate of procercoids was 0.33% (3/900) in Cyclops. In addition, the S. mansoni egg⁃positive rate was 1.48% (2/135) in cats and dogs. Conclusions　Sparganosis mansoni is prevalent in Jiangsu Province. Health education pertaining to the damages of sparganosis mansoni and the route of S. mansoni infections should be improved.

Impact of Toxoplasma gondii human infections on blood lipid levels

WU Li⁃feng, YE Xu⁃fang

2021, 33(6):  639. 

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Objective　To evaluate the impact of Toxoplasma gondii human infections on blood lipid levels. Methods　A total of 1 000 healthy volunteers that were randomly sampled from a tertiary hospital during the period from December 2017 through December 2019 were enrolled, and assigned into the infection group and the control group according to the detection of serum anti⁃T. gondii antibody using enzyme⁃linked immunosorbent assay (ELISA). The serum levels of total cholesterol (TC), high⁃density lipoprotein (HDL), low⁃density lipoprotein (LDL) and triglyceride (TG) were detected and compared between the two groups. Results　The seroprevalence of anti⁃T. gondii antibody was 8.40% in the study subjects, and there were no significant differences between the infection and control groups in terms of gender ([χ2] = 1.29, P > 0.05) or age ([χ2] = 1.41, P > 0.05). The mean serum LDL (t = 3.89, P < 0.05) and TC levels (t = 3.81, P < 0.05) were significantly higher in the infection group than in the control group, while no significant differences were seen between the two groups in terms of mean serum TG (t = 0.97, P > 0.05) or HDL levels (t = 0.75, P > 0.05). In addition, the proportions of abnormal LDL ([χ2] = 9.69, P < 0.01) and TC levels ([χ2] = 10.39, P < 0.01) were significantly greater in the infection group than in the control group, while no significant differences were found in the proportion of abnormal TG ([χ2] = 0.02, P > 0.05) or HDL level ([χ2] = 0.11, P > 0.05) between the two groups. Conclusion　T. gondii human infections affect blood lipid levels, and the individuals sero⁃positive for anti⁃T. gondii antibody have higher mean serum LDL and TC, as well as higher proportions of abnormal TC and LDL than sero⁃negative individuals.

Diagnosis and treatment of two imported cases with schistosomiasis haematobia in Fujian Province

XIE Xian⁃liang, XIE Han⁃guo, CHEN Yun⁃hong, GAO Lan⁃lin

2021, 33(6):  643. 

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ng author [Abstract]　Objective　To analyze the diagnosis and treatment of two imported cases with schistosomiasis haematobia, so as to provide insights into improving the diagnosis and treatment and avoiding misdiagnosis and mistreatment of imported schistosomiasis haematobia. Methods　The medical records and epidemiological data pertaining to the two cases were collected. The stool and urine samples were collected for identification of Schistosoma eggs using the Kato⁃Katz technique and direct smear method after centrifugal precipitation, and blood samples were collected for detection of anti⁃Schistosoma antibody. Following definitive diagnosis, the patients were given praziquantel therapy. Results　The patient 1, a Malagasy, was infected in Madagascar and returned to China for delivery. The case presented intermittent painless terminal hematuria symptoms, and showed no remarkable improvements following multiple⁃round treatments in several hospitals. In January 2017, she was found to be positive for anti⁃Schistosoma antibody, negative for feces test, and positive for S. haematobium eggs in urine test, and miracidia were hatched from eggs. Then, the case was diagnosed as schistosomiasis haematobia. Patient 2 worked in Republic of Malawi for many years, and presented intermittent painless terminal hematuria since October 2018; however, no definite diagnosis or effective treatment was received after admission to multiple hospitals. In March 2019, pathological examinations showed a number of eggs in the interstitium of the bladder mass, accompanied by a large number of eosinophils, which was consistent with schistosomiasis cystitis. In April 2019, he was tested positive for serum anti⁃Schistosoma antibody, negative for the fecal test, and had S. haematobium eggs in urine samples, with miracidia hatched from eggs. Then, the case was diagnosed as schistosomiasis haematobia. Following treatment with praziquantel at a dose of 60 mg/kg, all symptoms disappeared. Conclusions　Overseas imported schistosomiasis haematobia is likely to be misdiagnosed. The training pertaining to schistosomiasis control knowledge requires to be improved among clinical professionals, in order to avoid misdiagnosis and mistreatment. 　

An acute schistosomiasis case in Wuhan City imported from another province of China in 2020

ZUO Yu⁃ting, WANG Hao, ZHOU Shui⁃mao, HE Jian⁃min, SHI Xiao⁃ying, LUO Hua⁃tang, XU Ming⁃xing

2021, 33(6):  647. 

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An imported case of acute schistosomiasis was reported in Wuhan City in 2020. The case was infected with Schistosoma by contact with the infested water due to playing water in the Yangtze River when working out of Hubei Province. The patient visited four medical institutions and the duration from onset to definitive diagnosis was 20 days. The patient’s low awareness of schistosomiasis prevention and control knowledge and lack of diagnosis and treatment awareness for schistosomiasis among medical institutions were considered as main causes of the development of acute schistosomiasis and progression to severe case. Intensifying schistosomiasis health education among mobile populations and improving the awareness and capability of early diagnosis of schistosomiasis among clinicians are recommended.

Progress of researches on serine protease inhibitors for zoonotic cestode family Taeniidae

SONG Wei⁃yi, WANG Xin⁃rui, YU Ming⁃chuan, CUI Ya⁃xuan, QI Yu, SUN Shu⁃min

2021, 33(6):  650. 

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Serine protease inhibitor, a protein superfamily that inhibits the serine protease activity, protects hosts from parasitic infections. This review describes the spatial structure and classification of serine protease inhibitor, mechanisms underlying the interplay between serine protease inhibitor and host immune responses and current advances in serine protease inhibitor of zoonotic cestode family Taeniidae, so as to provide insights into the diagnosis of zoonotic tapeworm infections, discovery of therapeutic targets and screening of vaccine candidates.

Progress of researches on roles of dendritic cells in immune tolerance caused by Echinococcus infections

LI Wen⁃deng, HU Wang, XU Kai, NIE Ru, PANG Ming⁃quan, FAN Hai⁃ning

2021, 33(6):  655. 

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Dendritic cells (DCs), a type of antigen⁃presenting cells (APC), are recognized as an important regulator of immune response and immune tolerance, and play a critical role in the host innate immunity and adaptive immunity. Previous studies have shown that the long⁃term parasization of Echinococcus in the host is strongly associated with the host immune tolerance induced by DCs. This review summarizes the research progress of the role of DCs in host immune tolerance caused Echinococcus infection, aiming to provide the theoretical basis and insights into the management and immunotherapy of Echinococcus infections.

Progress of researches on the diagnostic techniques for schistosomiasis

SONG Lan⁃gui, WU Zhong⁃dao

2021, 33(6):  660. 

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Schistosomiasis is an important zoonotic parasitic disease, and is categorized as a neglected tropical disease by the World Health Organization. Following the concerted efforts for more than 70 years, great achievements have been made in the national schistosomiasis control program in China, and the prevalence, disability and mortality due to schistosomiasis has remarkably dropped. Nevertheless, the frequent identification of imported schistosomiasis and the resulting potential transmission risk in mainland China have been recently paid much attention following the implementation of the “Belt and Road Initiative” and the China⁃Africa Cooperation Forum. This review describes the advances in the diagnostic tools for schistosomiasis, including pathogenic techniques, immunodiagnostic techniques and nucleic acid assays, in order to consolidate schistosomiasis control achievements and promote the capability for detection of external biological safety risks.