Table of Content

08 December 2020, Volume 32 Issue 6

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Endemic status of schistosomiasis in People’s Republic of China in 2019

ZHANG Li-Juan, XU Zhi-Min, DANG Hui, LI Yin-Long, Lü Shan, XU Jing, LI Shi-Zhu, ZHOU Xiao-Nong

2020, 32(6):  551. 

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This report presented the endemic status of schistosomiasis in the People’s Republic of China at a national level in 2019, and analyzed the data collected from the national schistosomiasis prevention and control system and 455 national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai, Zhejiang, Fujian, Guangdong and Guangxi continued to consolidate the achievements of schistosomiasis elimination, Sichuan Province achieved transmission interruption, Jiangsu newly achieved the standard of transmission interruption and 5 provinces of Yunnan, Hubei, Anhui, Jiangxi and Hunan maintained transmission control by the end of 2019. There were 450 endemic counties (cities, districts) endemic for schistosomiasis, including 28 500 endemic villages covering 70 667 800 people at risk of infections. Among the 450 endemic counties (citis, districts), 66.89% (301/450), 28.44% (128/450) and 4.67% (21/450) kept the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2019, a total of 30 170 advanced schistosomiasis cases were documented in China. In 2019, a total of 12 090 712 individuals received inquiry examinations and 1 740 764 were positive; 5 158 369 individuals received serological tests and 89 753 were sero?positive. A total of 327 475 individuals received stool examinations and 5 were positive, including one case of acute schistosomiasis. In 2019, snail survey was performed in 19 726 endemic villages in China and Oncomelania snails were found in 7 322 villages, accounting for 37.12% of all surveyed villages, with 6 villages with emerging snail habitats. Snail survey covered an area of 585 286.24 hm2 and 174 270.42 hm2 snail habitats were found, including emerging snail habitats of 64.20 hm2; however, no infected snails were identified. In 2019, a total of 605 965 bovines were raised in the schistosomiasis endemic areas of China, and 183 313 received serological examinations, with 1 176 positives detected, while 134 978 bovines received stool examinations, with 7 positives identified. In 2019, there were 28 557 patients with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 1 008 083 person?times; there were 7 bovines with schistosomiasis receiving praziquantel chemotherapy, and 296 053 herd?times expanded chemotherapy was given to bovines. In 2019, snail habitats at an area of 128 754.26 hm2 were given chemical treatment, and the actual area of chemical treatment was 69 605.55 hm2, while environmental improvements were performed in snail habitats covering an area of 2 847.00 hm2. Data from the 455 national schistosomiasis surveillance sites of China showed that the mean Schistosoma japonicum infection rates were both zero in humans and bovines in 2019, and no infected snails were found. The results demonstrate that the overall endemic situation of schistosomiasis remains at a lower infection level in China; however, there is still a risk of schistosomiasis transmission. To achieve the target set in the National Thirteenth Five?Year Plan for Schistosomiasis Control and consolidate the achievements of schistosomiasis control, precision control on schistosomiasis still needs to be reinforced in China.

Study on the factors affecting the degradation of niclosamide in the soil

2020, 32(6):  559-564. 

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g author [Abstract]　Objective　To investigate the factors affecting the degradation of niclosamide in the soil, so as to provide the evidence for the assessment of the environmental safety in the field snail control with niclosamide. Methods　A high performance liquid chromatography was established for the determination of niclosamide in the field. Then, the degradation of niclosamide was investigated in soils with different moistures (10%, 30%, 50%, 70% and 90%), temperatures [(15 ± 1), (25 ± 1), (35 ± 1) ℃], initial concentrations (1, 5, 10 mg/kg) and in sterilized and non-sterilized soils. In addition, the degradation of niclosamide was fitted with the first-order kinetics equation, and the degradation half-life was calculated. Results　The niclosamide residues gradually decreased over time in soils with different moistures, and a higher rate of degradation was seen in soils with a higher moisture. The degradation half-life of niclosamide reduced from 4.258 d in the soil with a 10% moisture to 2.412 d in the soil with a 90% moisture. The niclosamide residues gradually decreased over time in soils with different temperatures, and a higher rate of degradation was seen in soils with a higher temperature. The degradation half-life of niclosamide reduced from 4.398 d in the soil with a temperature of (15 ± 1) ℃ to 2.828 d in the soil with a temperature of (35 ± 1) ℃. The degradation half-lives of niclosamide were 3.212, 3.333 d and 3.448 d in soils containing niclosamide at initial concentrations of 1, 5 mg/kg and 10 mg/kg, and > 30 d and 3.273 d in sterilized and non-sterilized soils. Multiple linear regression analysis revealed that soil microorganisms (P = 0.010), moisture (P = 0.000) and temperature (P = 0.002) affected the half-life of niclosamide degradation. Conclusion 　The degradation of niclosamide in soils fits the first-order kinetics equation, and presence of microorganisms, a high temperature and high moisture may accelerate the degradation of niclosamide in the soil.

Endemic situation of schistosomiasis in national surveillance sites of Hubei Province from 2015 to 2019

2020, 32(6):  565. 

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Objective　To analyze the changing tendency in the endemic situation of schistosomiasis in the national surveillance sites of Hubei Province, so as to provide the scientific evidence for facilitating the progress towards the elimination of schistosomiasis in the province. Methods　According to the National Schistosomiasis Surveillance Scheme (2014 version), a total of 65 national schistosomiasis surveillance sites were assigned in Hubei Province, and the Schistosoma japonicum infections in humans, domestic animals, snails and wild feces were monitored in these national surveillance sites from 2015 to 2019. All data pertaining to the surveillance results were descriptively analyzed. Results　There were 151 159 person?time local residents and 70 928 person?time mobile populations screened for S. japonicum infections in the 65 national surveillance sites of Hubei Province from 2015 to 2019, and the seroprevalance of S. japonicum infections reduced from 3.45% (1 077/31 197) in 2015 to 1.57% (431/27 371) in 2019 among local residents and from 1.06% (98/9 249) in 2015 to 0.81% (116/14 318) in 2019 among mobile populations. During the period from 2015 through 2019, there were 22 egg?positive local residents and 2 egg?positive mobile populations identified in 2015, with 0.07% and 0.02% prevalence rates of S. japonicum infections, respectively. During the 5?year period, a total of 7 025 herd?time domestic animals examined for S. japonicum infections, with no infections detected, and a total of 2 035 wild feces were tested, with no egg?positives identified in the 65 national surveillance sites of Hubei Province. Snail survey was conducted covering 28 767.35 hm2 during the 5?year period, and the area of snail habitats ranged from 1 609.82 to 2 119.81 hm2. The mean density of living snails and occurrence of frames with snails reduced from 0.360 5 snails/0.1 m2 and 11.26% in 2015 to 0.175 9 snails/0.1 m2 and 8.43% in 2019, respectively, and no S. japonicum infection was found in snails during the 5?year period. In addition, no snails were found in the potential schistosomiasis transmission foci in the two national surveillance sites in the Three Gorges Dam. Conclusions　The overall endemic situation of schistosomiasis appears a tendency towards a decline in Hubei Province during the period from 2015 through 2019; however, the schistosomiasis transmission risk remains. Improving the surveillance system of schistosomiasis and increasing the sensitivity and performance of the surveillance system are required to provide insights into the implementation of precision control strategy and interventions in Hubei Province.

Immune characteristics of Plasmodium reinfections in mice following chloroquine cure of primary Plasmodium infections

2020, 32(6):  569. 

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Objective　To investigate the disease progression and immunoprotective characteristics in mice re?infected with homogeneous/heterogeneous Plasmodium strains following cure of Plasmodium infections with chloroquine at the peak of parasitemia. Methods　C57BL/6 mice were infected with the non?lethal P. yoelii 17XNL strain, and half of mice were given treatment with chloroquine at the peak of parasitemia (9 days post?infection), while the other mice were self?cured naturally. Then, all cured mice were re?infected with the equivalent lethal P. yoelii 17XL or P. berghei ANKA strain 90 days following primary Plasmodium infections. The parasitemia levels during primary infections and reinfections were measured by microscopic examinations of Giemsa?stained thin blood films, and the levels of the IgG antibody in sera and the percentages of memory T cell subsets in spleen cells were detected in mice using ELISA and flow cytometry before and after parasite reinfections, respectively. Results　Following primary infections with the P. yoelii 17XNL strain, the serum IgG antibody levels were (5.047 ± 0.924) pg/mL in the self?cured mice and (4.429 ± 0.624) pg/mL in the chloroquine?treated mice, respectively (t = 0.437, P > 0.05), which were both significantly higher than that in the uninfected mice (1.624 pg/mL ± 0.280 pg/mL) (F = 22.522, P < 0.01). There was no significant difference in the serum IgG antibody level among self?cured and chloroquine?treated mice re?infected with the P. yoelii 17XL strain or the P. berghei ANKA strain (F = 0.542, P > 0.05); however, the serum IgG antibody levels were all significantly higher in self?cured and chloroquine?treated mice re?infected with the P. yoelii 17XL strain [(15.487 ± 1.173) pg/mL and (15.965 ± 1.150) pg/mL] or the P. berghei ANKA strain [(14.644 ± 1.523) pg/mL and (15.185 ± 1.333) pg/mL] relative to primary infections (F = 67.383, P < 0.01). There was no significant difference in the proportion of CD4+ [(34.208 ± 2.106), (32.820 ± 1.930), (34.023 ± 2.289), (35.608 ± 1.779) pg/mL] or CD8+ T memory cells [(17.935 ± 2.092), (18.918 ± 2.823), (17.103 ± 1.627), (17.873 ± 1.425) pg/mL] in self?cured and chloroquine?treated mice with primary infections with the P. yoelii 17XNL strain followed by re?infections with the P. yoelii 17XL strain or the P. berghei ANKA strain (F = 0.944 and 0.390, both P > 0.05); however, the proportions of the CD4+ or CD8+ T memory cells were significantly greater in self?cured and chloroquine?treated mice with primary infections with the P. yoelii 17XNL strain followed by re?infections with the P. yoelii 17XL strain or the P. berghei ANKA strain than in mice with primary infections (F = 50.532 and 21.751, both P < 0.01). Conclusions　The cure of murine Plasmodium infections with chloroquine does not affect the production of effective immune protections in mice during parasite re?infections. Following a primary infection, mice show a protection against re?infections with either homogeneous or heterogeneous Plasmodium strains, and a higher?level resistance to re?infections with homogeneous parasite strains is found than with heterogeneous strains.

Prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City

HU Zhu-Hua, CHEN Hui-Hui, QIAN Ke, NING Chao-Qun, PENG Guo-Hua, YU Ying-Fang, ZHOU Xian-Feng, CHU Yan-Hong, XU Dan, CHEN Jia-Xu, TIAN Li-Guang, LI Hui

2020, 32(6):  577. 

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Objective　To investigate the prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City. Methods　A cross?sectional questionnaire survey was conducted among AIDS patients in Nanchang City during the period between May and September, 2016. B. hominis infection was detected in patients’ stool samples using a PCR assay, and the CD4+ T cell count was measured in subjects’ blood samples. In addition, the risk factors of B. hominis infection in AIDS patients were identified using univariate and multivariate logistic regression analyses. Results　A survey was conducted in Nanchang City from May to September 2016. A total of 505 AIDS patients were investigated, and the prevalence of B. hominis infection was 4.16%. Univariate analysis revealed that B. hominis infection correlated with the occupation ([χ2] = 8.595, P = 0.049), education level ([χ2] = 14.494, P = 0.001), type of daily drinking water ([χ2] = 10.750 , P = 0.020), root of HIV infections ([χ2] = 8.755, P = 0.026) and receiving anti?HIV therapy ([χ2] = 23.083, P = 0.001) among AIDS patients, and multivariate logistic regression analysis identified daily direct drinking of tap water as a risk factor of B. hominis infections [odds ratio (OR) = 7.988, 95% confidential interval (CI): (1.160, 55.004)] and anti?HIV therapy as a protective factor of B. hominis infection [OR = 0.183, 95% CI: (0.049, 0.685)]. Conclusions　The prevalence of B. hominis is 4.16% among AIDS patients in Nanchang City. Daily direct drinking of tap water is a risk factor, and anti?HIV therapy is a protective factor of B. hominis infection among AIDS patients living in Nanchang City.

Identification, molecular structure and expression characteristics of Torso?like gene in Anopheles dirus

ZHU Ling-Qian, HU Xiao-Kang, XU Jing, LI Shi-Zhu, FENG Xin-Yu

2020, 32(6):  584. 

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Objective　To characterize Torso?like (tsl) gene and investigate its expression characteristics in Anopheles dirus, so as to provide a theoretical basis for subsequent functional studies of the tsl gene. Methods　According to the coding sequences of Drosophila melanogaster and An. gambiae tsl genes, the complete genome of An. dirus was retrieved and the An. dirus tsl gene was characterized. Specific primers were designed and the target gene was amplified using PCR and reverse?transcription PCR assays. The physicochemical properties, signal peptide, transmembrane structure, secondary structure and tertiary structure of the encoded protein TSL were analyzed using bioinformatics tools, and a phylogenetic analysis was performed. In addition, the specific expression of the tls gene was detected in various tissues of An. dirus using a quantitative real?time PCR assay. Results 　The An. dirus tsl gene was 16 751 bp in length with a CDS region of 1 134 bp, encoding 377 amino acids, and the encoded TSL protein was a stably hydrophilic protein. The TSL protein was predicted to be a secretory protein that was located in extra?membrane regions containing signal peptides. The secondary structure of the TSL protein contained α?helix (51.72%), extended strand (12.20%), β?bridge (4.78%) and random coil (31.30%) in the secondary structure, and a 3D homology model was generated using 5cj9.1.A as a template. Phylogenetic analysis revealed a close genetic relationship in the TSL protein between An. dirus and An. farauti. In addition, quantitative real?time PCR assay detected the tsl gene expression in the head, chest, abdomen and foot of An. dirus, with the highest expression in the head and low expression in the foot. Conclusion　The tsl gene is characterized in An. dirus at a genomic level, and the prediction of the TSL protein structure and the elucidation of the tissue?specific tsl gene expression in An. dirus provide a basis for the further studies on the gene functions.

Exhaustion of CD8⁺ T cell immune functions in spleen of mice with different doses of Echinococcus multilocularis infections

HOU Xin-Ling, LI Liang, LI Ling-Hui, LI Jing, WANG Hui, JIANG Tie-Min, ZHANG Rui-Qing, SHAO Ying-Mei, ZHANG Chuan-Shan

2020, 32(6):  591. 

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Objective　To examine the changes in the immune functions of CD8+ T cells in the spleen of mice following Echinococcus multilocularis infections at various doses and at different time points. Methods　The E. multilocularis protoscoleces were collected, and E. multilocularis infection was modeled in mice via the hepatic portal vein at doses of 50 (low?dose), 500 (medium?dose) and 2 000 protoscoleces (high?dose), while physiological saline served as controls. Mouse spleen was isolated 2 (early?stage), 12 (middle?stage) and 24 weeks post?infection (late?stage), and spleen lymphocytes were harvested. The phenotype of memory CD8+ T cells and 2B4 expression were quantified in the mouse spleen, and the secretion of interferon (IFN)?γ, tumor necrosis factor (TNF)?α, interleukin (IL)?17A and IL?10 was measured. Results　A central?memory phenotype was predominant in the CD8+ T cells in the spleen of mice at the early stage of high?dose protoscolece infections, and the proportion of central?memory CD8+ T cells was significantly greater in the high?dose group than in the control group (35.50% ± 2.00% vs. 25.90% ± 2.46%, P < 0.01), while a effector? memory phenotype was predominant in the CD8+ T cells in the spleen of mice at the late stage of medium? and high?dose protoscolece infections, and the proportions of effector?memory CD8+ T cells were significantly greater in the medium? (25.70% ± 4.12%) and high?dose group (28.40% ± 4.12%) than in the control group (10.50% ± 6.45%) (P < 0.05). The proportions of the central?memory CD8+ T cells were significantly higher in the high?dose group than at middle and late stages than at the early stage (P < 0.01), and the proportion of effector?memory CD8+ T cells was significantly greater in the high?dose group at the late stage than at early and middle stages (P < 0.05). The secretion of IFN?γ and IL?17A by spleen CD8+ T cells was elevated in the low? and medium?dose groups at the early stage of infection, and high?dose protoscolece infection promoted the secretion of IFN?γ and TNF?α by spleen CD8+ T cells; however, the levels of IFN?γ and TNF?α were significantly lower at the late stage than at the early and middle stages (P < 0.05). In addition, high 2B4 expression was detected in spleen CD8+ T cells in the middle? and high?dose groups at the late stage of infection, and the 2B4 expression was significantly higher in the medium? (4.73% ± 1.56%) and high?dose groups (4.94% ± 1.90%) than in the low?dose group (2.49% ± 0.58%) and the control group (2.92% ± 0.60%) (P < 0.05). Conclusions　E. multilocularis may be killed and eliminated through the host immune responses at the middle and late stages of low? and medium?dose protoscolece infections, while high?dose protoscolece infections may trigger the upregulation of 2B4 expression in mouse spleen CD8+ T cells at the late stage, which leads to immune exhaustion and the resultant chronic infections.

Evaluation of the effect of the integrated echinococcosis control program in Ningxia Hui Autonomous Region from 2011 to 2018

WU Xiang-Lin, DUAN Hong-Ju, QI Rong-Ting, YAN Fang, FU Yi-Ren, MA Tian-Bo

2020, 32(6):  598. 

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Objective　To evaluate the effect of the integrated echinococcosis control program in Ningxia Hui Autonomous Region from 2011 to 2018. Methods　A package of integrated interventions were employed for echinococcosis control in 22 counties (districts) of Ningxia Hui Autonomous Region from 2011 to 2018, including screening of human echinococcosis, treatment of echinococcosis patients, deworming of domestic dogs and monitoring of infections, surveillance of echinococcosis in bovines and sheep, health education. The detection of human echinococcosis, seroprevalence of anti?Echinococcus antibody in children at ages of 6 to 12 years, the Echinococcus coproantigen?positive rate in domestic dogs, prevalence of echinococcosis in bovines and sheep, and the awareness of echinococcosis control knowledge were investigated and compared during the period between 2011 and 2018. Results　The detection of human echinococcosis appeared a decline tendency in Ningxia Hui Autonomous Region over years during the period from 2011 to 2018 (χ2trend = 82.22, P < 0.05), and the prevalence of human echinococcosis decreased from 0.31% in 2011 to 0.15% in 2018. The seroprevalence of anti?Echinococcus antibody appeared a decline tendency in children at ages of 6 to 12 years over years (χ2trend = 439.64, P < 0.01), and the prevalence of anti?Echinococcus antibody decreased from 6.12% in 2011 to 0.67% in 2018. The Echinococcus coproantigen?positive rate appeared a decline tendency in domestic dogs over years (χ2trend = 260.33, P < 0.05), and the prevalence of anti?Echinococcus antibody decreased from 7.11% in 2011 to 0.75% in 2018. The prevalence of bovine and sheep echinococcosis reduced from 3.26% and 5.08% in 2011 to 1.35% and 0.76% in 2018, and Echinococcus predominantly parasitized in bovine (92.00%) and sheep (93.94%) livers. A total of 63 stool samples were collected from red fox, wolf and badger in Xiji and Haiyuan counties of Ningxia Hui Autonomous Region in 2013 and 2014, with no Echinococcus coproantigen?positives detected, and 107 domestic cats and 3 domestic dogs were dissected in these two counties, with no Echinococcus found. A total of 6 046 wild mice were dissected in Xiji County, Yuanzhou District and Haiyuan County of Ningxia Hui Autonomous Region from 2016 to 2019, and the prevalence of E. multilocularis was 0.31%. The awareness of echinococcosis control knowledge appeared an increasing tendency in Ningxia Hui Autonomous Region over years from 2011 to 2018 (χ2trend = 3 367.97, P < 0.01), and the awareness increased from 21.83% in 2011 to 72.24% in 2018. Conclusions　The integrated echinococcosis control program achieves a remarkable effect in Ningxia Hui Autonomous Region, and the transmission of echinococcosis has been preliminarily controlled. However, the echinococcosis transmission risk remains in few regions, and the integrated echinococcosis control program remains to be reinforced.

Evaluation of the diagnostic efficiency of three anti-Echinococcus antibody?based assays for the serodiagnosis of echinococcosis

YANG Zhi-Yong, TIAN Feng-Yuan, CAI Qi-Gang, ZHU Wen-Jun, HAN Xiu-Min

2020, 32(6):  605. 

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Objective　To evaluate the efficiency of three Chinese commercial anti?Echinococcus antibody?based assays for the serodiagnosis of echinococcosis. Methods　A total of 142 sera from cystic echinococcosis patients, 89 sera from alveolar echinococcosis and 39 sera from healthy controls were sampled, and detected by kits A (ELISA), B (ELISA) and C (colloidal gold immunoassay). The routine blood testing results and biochemical parameters were compared between the cystic and alveolar echinococcosis patients, and the associations of the absorbance (A value) of the serum specific antibody detected by A and B kits with the routine blood testing results and biochemical parameters were examined in echinococcosis patients. In addition, the performance of these three assays for the serodiagnosis of echinococcosis was evaluated. Results　There were no significant differences between the cystic and alveolar echinococcosis patients in terms of the median white blood cell count (WBC), neutrophil count (NEU), monocyte count (MONO), basophil count (BASO), alanine aminotransferase concentration (ALT), aspirate aminotransferase concentration (AST), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL) (all P values > 0.05), and higher median lymphocyte count (LYM) and albumin levels (ALB) were detected in cystic echinococcosis patients than in alveolar echinococcosis patients (both P values < 0.05), while the median eosinophil count (EOS) was greater in the alveolar echinococcosis patients than in the cystic echinococcosis patients (P < 0.01). The A value of the serum specific antibody detected by kit A showed a linear positive correlation with WBC (rs = 0.153, P < 0.05) and EOS (rs = 0.174, P < 0.05), and a linear negative correlation with TBIL (rs = -0.134, P < 0.05) and IBIL (rs = -0.146, P < 0.05), while the A value of the serum specific antibody detected by kit B showed a linear positive correlation with WBC (rs = 0.257, P < 0.01), NEU (rs = 0.203, P < 0.01), MONO (rs = 0.159, P < 0.05), EOS (rs = 0.330, P < 0.01), ALT (rs = 0.171, P < 0.01) and AST (rs = 0.160, P < 0.05), and a linear negative correlation with ALB (rs = -0.168, P < 0.05). The overall coincidence rate, sensitivity, specificity, Youden’s index and Kappa value of A, B and C kits were 86.30%, 69.63% and 91.48%; 84.42%, 64.94% and 92.21%; 97.44%, 97.44% and 87.18%; 0.82, 0.62 and 0.79; and 0.600, 0.337 and 0.750 for the diagnosis of echinococcosis, respectively. The overall coincidence rate, sensitivity, specificity and Youden’s index of A, B and C kits were 84.54%, 64.64% and 71.82%; 80.99%, 55.63% and 68.31%; 97.44%, 97.44% and 87.18%; and 0.78, 0.53 and 0.56 for the diagnosis of cystic echinococcosis, respectively, while the overall coincidence rate, sensitivity, specificity and Youden’s index of A, B and C kits were 92.19%, 85.16% and 85.16%; 89.89%, 79.78% and 84.27%; 97.44%, 97.44% and 87.18%; and 0.87, 0.77 and 0.72 for the diagnosis of alveolar echinococcosis, respectively. The C kit showed cross?reactions in the serodiagnosis of cystic echinococcosis and alveolar echinococcosis. There were no significant difference in the area under the receiver operating characteristic curve (ROC) between A and B kits for the diagnosis of echinococcosis (0.970 vs. 0.948, Z = 1.618, P > 0.05), and there was a high agreement between A and B kits in the diagnosis of echinococcosis (Kappa = 0.585, P < 0.01). Conclusions　The three commercial anti?Echinococcus antibody?based kits exhibit a higher serodiagnostic efficiency for alveolar echinococcosis than for cystic echinococcosis. The A kit shows a high sensitivity and specificity for the diagnosis of echinococcosis, and has a relatively stable diagnostic performance and fewer influencing factors, which is suitable for the pre?surgical preliminary diagnosis and post?surgical follow?up monitoring of serum anti?Echinococcus antibody, while the C kit shows a high sensitivity and specificity for the diagnosis of echinococcosis, and is easy to perform and high in reporting rate, which is feasible for initial screening of echinococcosis.

Analysis of drug-resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province in 2015 and 2016

NIE Guang-Kui, XU Chao, WEI Qing-Kuan, LI Jin, XIAO Ting, SUN Hui, KONG Xiang-Li, YIN Kun, ZHAO Gui-Hua, ZHANG Ben-Guang, YAN Ge, HUANG Bing-Cheng

2020, 32(6):  612. 

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Objective　To investigate the drug?resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province. Methods　From 2015 to 2016, blood samples were collected from imported P. falciparum malaria patients returning from Equatorial Guinea to Shandong Province, and genome DNA of the malaria parasite was extracted. The drug?resistant Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum were amplified using a PCR assay, followed by DNA sequencing, and the sequences were aligned. Results The target fragments of all 5 drug?resistant genes of P. falciparum were successfully amplified and sequenced. There were 72.8%, 18.6%, and 8.6% of P. falciparum parasites carrying the wild?, mutant?, and mixed?type Pfcrt gene, respectively, and all mutant haplotypes were CVIET (the underline indicates the mutation site). There were 20.0%, 61.4% and 18.6% of P. falciparum parasites carrying the wild?, mutant?, and mixed?type Pfmdr1 gene, respectively, and the mutant haplotypes mainly included YF and NF (the underlines indicate the mutation sites). There were 1.4%, 98.6%, and 0 of P. falciparum parasites carrying the wild?, mutant?, and mixed?type Pfdhfr gene, respectively, and AIRNI was the predominant mutant haplotype (the underline indicates the mutation site). There were 1.4%, 94.3%, and 4.3% of P. falciparum parasites carrying the wild?, mutant?, and mixed?type Pfdhps gene, respectively, and SGKAA was the predominant mutant haplotype (the underline indicates the mutation site). The complete drug?resistant IRNGE genotype consisted of 8.6% of the Pfdhfr and Pfdhps genes, and the K13 gene A578S mutation occurred in 1.4% of the parasite samples. Conclusion　There are mutations in the Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum imported from Equatorial Guinea to Shandong Province, with a low frequency in the Pfcrt gene mutation and a high frequency in the Pfmdr1, Pfdhfr, and Pfdhps gene mutations, and the K13 gene A578S mutation is detected in the parasite samples.

Transcriptome sequencing and bioinformatics analysis of Tyrophagus putrescentiae

JIA Hao-Yuan, ZHOU Ying, CUI Yu-Bao, WANG Ting-Ting

2020, 32(6):  618. 

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Objective　To obtain the transcriptome data of Tyrophagus putrescentiae, so as to provide insights into the subsequent functional studies. Methods　The mixture of male and female T. putrescentiae was sequenced using the Illumina HiSeqTM 2000 high?throughput sequencing platform. Unigenes were obtained after assembling the sequencing data using the Trinity software and compared with the protein sequences in the RefSeq non?redundant protein sequence (NR) database, nucleotide sequence (NT) database, Swiss?Prot database, Kyoto encyclopedia of genes and genomes (KEGG) database and clusters of orthologous groups (COG) database, and the function of the Unigenes was annotated. In addition, the coding DNA sequences (CDS) were predicted through alignment of the Unigenes in NR and Swiss?Prot protein databases. The SSR loci were identified by analysis of the Unigenes in T. putrescentiae with the MISA software, and the SNPs were detected using the SOAPsnp technique. Results　A total of 4.67 GB high?quality data were obtained from raw sequencing data. A total of 51 271 Unigenes were obtained after assembling the sequencing data, with a total length of 41 848 995 nucleotide (nt) and a mean length of 816 nt. A total of 29 053 annotated Unigenes were obtained following comparisons with the public protein databases, and 27 443 CDS were predicted. In addition, there were 23 092 SSR loci and 148 027 SNPs identified. Conclusions　The database of T. putrescentiae transcriptome is created by sequencing, and a large number of T. putrescentiae transcripts are obtained, which provides a basis for the subsequent functional studies of allergy?related genes.

Analysis of factors affecting health-related behaviors for schistosomiasis prevention and control among primary and secondary school students in Sichuan Province

ZHANG Yu, LIU Yang, LI Rong-Zhi, LU Ding, SHANG Jing-Ye, CHEN Lin

2020, 32(6):  623. 

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Objective　To analyze the influencing factors of health?related behaviors for schistosomiasis prevention and control among primary and secondary school students in Sichuan Province using a multilevel and multivariate logistic model, so as to provide the theoretical evidence for developing the schistosomiasis prevention and control strategy among primary and secondary school students in Sichuan Province. Methods　A multi?stage sampling was conducted among 63 schistosomiasis?endemic counties (districts) in Sichuan Province. Five endemic townships were sampled from each county (district), and 100 Grade 4 to 6 students in each primary school and 100 Grade 1 to 3 students in each secondary school were sampled from each township as the study subjects. The health?related behaviors for schistosomiasis prevention and control were investigated using a questionnaire survey, and factors affecting infested water contact behaviors were identified using univariate and multilevel logistic analyses. Results　Among the 62 200 questionnaires distributed, there were 59 134 recovered, and 56 510 were qualified. The qualified 56 510 respondents included 22 955 secondary school students and 33 555 primary school students, and 28 297 male students and 28 213 females. A higher proportion of infested water contacts was seen in male students than in females (P < 0.001), and the students living in heavily endemic areas had a higher proportion of infested water contacts than those in mildly endemic areas (P < 0.001). In addition, there was no significant difference in the proportion of infested water contacts between primary and secondary school students (P > 0.05). Multilevel and multivariate logistic analyses revealed a lower proportion of infested water contacts with the increase of knowledge, belief and self?efficacy levels (P < 0.001), and there was a cluster of infested water contacts among students at a county scale (P < 0.001). Conclusions　There is a cluster of infested?water contact behaviors among primary and secondary school students at a county scale in Sichuan Province. Individual and environmental factors should be considered during the formulation of health education strategy and interventions for schistosomiasis among primary and secondary school students.

Quality of malaria blood smears from fever patients in Zibo City, Shandong Province from 2011 to 2018

XU Jin, HAO Jun-Feng, HAN Chao, ZHANG Ben-Guang

2020, 32(6):  627. 

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Objective　To analyze the quality of malaria blood smears from fever patients in Zibo City from 2011 to 2018, so as to provide the scientific evidence for the development of the malaria post?elimination surveillance strategy. Methods　All negative malaria blood smears from fever patients reexamined in the municipal microscopic examination station and all positive blood smears in Zibo City during the period from 2011 to 2018 were reexamined, and the blood smear preparation, dyeing, cleanliness and reexamination results were analyzed. Results　A total of 2 141 negative malaria blood smears and 39 positive blood smears were re?reviewed by the municipal microscopic examination station of Zibo City from 2011 to 2018, with a 99.44% qualification rate of negative blood smears preparation, a 97.62% qualification rate of dyeing, a 93.65% qualification rate of cleanliness, and a 100% consistence with the re?review, and no missing diagnosis was found. A total of 39 positive blood smears were re?reviewed, with a 46.15% qualification rate of blood smears preparation, a 61.54% qualification rate of dyeing, a 76.92% qualification rate of cleanliness, and a 97.44% consistence with the re?review, and a blood smear mistaking the Plasmodium species was found. There were significant differences in the qualification rate of blood smears preparation and dyeing among all districts (counties) in Zibo City (all P values < 0.05), and no significant difference was detected in the qualification rate of blood smear cleanliness ( [χ2] = 13.72, P > 0.05), while significant differences were seen in the qualification rate of blood smears preparation, dyeing and cleanliness each year from 2011 to 2018 (all P values < 0.05). Conclusion　The quality of malaria blood smears is high in all districts of Zibo City; however, the quality of city?level blood smears remains to be improved. Further actions to improve the training of grassroots microscopic examinations and quality control of malaria blood smears are required to ensure the capability of microscopic examinations of Plasmodium during the malaria post?elimination stage.

Re-examination of malaria diagnosis in Hubei Provincial Malaria Diagnostic Reference Laboratory from 2017 to 2019

SUN Ling-Cong, DONG Xiao-Rong, TU Zhen, WU Dong-Ni, LIN Wen, ZHOU Xiao-Rong, ZHU Hong

2020, 32(6):  631. 

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Objective　To analyze the re?examination results of malaria cases captured from the National Notifiable Communicable Disease Reporting System in Hubei Provincial Malaria Diagnostic Reference Laboratory from 2017 to 2019, so as to provide the scientific evidence for improving the malaria control capability in the province. Methods　Microscopy and nested PCR assay were performed to re?examine the diagnosis of malaria cases registered in the National Notifiable Communicable Disease Reporting System in Hubei Provincial Malaria Diagnostic Reference Laboratory from 2017 to 2019, and the coincidences of malaria diagnosis and malaria parasite species were evaluated. Results　A total of 410 malaria cases were reported in Hubei Province from 2017 to 2019 according to the data retrieved from the National Notifiable Communicable Disease Reporting System. Among the 407 samples re?examined by Hubei Provincial Malaria Diagnostic Reference Laboratory from 2017 to 2019, the diagnosis 374 malaria cases were confirmed, with an overall coincidence of 91.89% (374/407) for malaria diagnosis and 89.04% (333/374) for parasite species identification. The coincidence rates of malaria diagnosis and parasite species identification were 50.00% to 100.00% and 66.67% to 100.00% in 16 cities (prefectures) of Hubei Province during the re?examinations, which both varied in regions (χ2 = 40.46 and 42.30, both P values < 0.01). The coincidence rates of Plasmodium falciparum, P. vivax, P. malariae and P. ovale identification were 95.80%, 100.00%, 58.33% and 51.92% during the re?examinations, respectively (χ2 = 76.66, P < 0.01). The consistency rate between microscopic and nested PCR results was 89.83% (362/403). Conclusion　The overall diagnostic quality of malaria is high in medical institutions at all levels in Hubei Province; however, the diagnostic capability of malaria remains to be improved in some regions.

Seroprevalence and risk factors of Toxoplasma gondii infections among high-risk populations in Changzhou City

XIE Yi-Qing, HE Ming-Zhen, ZHANG Wu-Hong

2020, 32(6):  635. 

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Objective　To understand the prevalence and risk factors of Toxoplasma gondii infections among high?risk populations in Changzhou City, so as to provide the scientific basis for formulating effective control measures of toxoplasmosis. Methods　Four types of high?risk populations living in Changzhou City were recruited from 2016 to 2018 as the study subjects, including HIV/AIDS patients, cancer patients, pregnant women and livestock and poultry breeding or processing workers. Each subject was investigated for the knowledge on knowledge, attitude and practice of toxoplasmosis prevention and control. In addition, serum specific IgG and IgM antibodies against T. gondii were detected, and the risk factors of T. gondii infections were identified. Results　A total of 900 participants at high risk of T. gondii infections were investigated in Changzhou City from 2016 to 2018, including 150 HIV/AIDS patients, 250 cancer patients, 250 pregnant women and 250 livestock and poultry breeding or processing workers. The overall awareness rate of toxoplasmosis prevention and control knowledge was 16.8% (151/900), and the awareness rate was significantly greater in women than in men ([χ2] = 41.34, P < 0.05). The awareness rate of toxoplasmosis prevention and control reduced with ages ([χ2] = 147.78, P < 0.05), and increased with the education level ([χ2] = 166.42, P < 0.05). In addition, there was an occupation?specific awareness rate of toxoplasmosis prevention and control ([χ2] = 92.26, P < 0.05), and the highest awareness rate was seen in cadres and staff (47.2%, 34/72). Among all high?risk populations, 34.6% (311/900) had frequent contacts with cats/dogs, 40.4% (364/900) raised cats/dogs at home, 0.9% (8/900) ate raw meat, and 15.8% (142/900) separated chopping boards for raw and cooked food. Among the participants aware of toxoplasmosis prevention and control knowledge, 24.5% (37/151) contacted cats/dogs frequently, which was significantly lower than those not aware of toxoplasmosis prevention and control knowledge (36.6%, 274/749) ([χ2] = 8.11, P < 0.05), and 35.1% (53/151) separated chopping boards for raw and cooked food, which was significantly higher than those not aware of toxoplasmosis prevention and control knowledge (11.9%, 89/749) ([χ2] = 50.97, P < 0.05). The overall seroprevalence of T. gondii infections was 11.0% (99/900), and the positive rates of IgG antibodies against T. gondii were 6.0%, 13.9%, 4.8% and 17.3% in HIV/AIDS patients, livestock and poultry breeding or processing workers, pregnant women and cancer patients, respectively ([χ2] = 25.87, P < 0.05). A higher seroprevalence of T. gondii infection was seen in men than in women ([χ2] = 8.88, P < 0.05), and the seroprevalence increased with ages ([χ2] = 37.03, P < 0.05) and reduced with education levels ([χ2] = 25.07, P < 0.05). There was an occupation?specific seroprevalence of T. gondii infection ([χ2] = 22.09, P < 0.05), and the highest seroprevalence was detected in peasants (57/330, 17.3%). Conclusions　The awareness of toxoplasmosis prevention and control knowledge is low among high?risk populations in Changzhou City. Health education pertaining to toxoplasmosis prevention and control requires to be strengthened in cancer patients and livestock and poultry breeding or processing workers who have a high seroprevalence of T. gondii infections, so as to change the poor behavior styles.

Effect of integrated schistosomiasis control measures on Oncomelania snails in river channels connecting the Yangtze River in Nanjing City

XIE Chao-Yong, WANG Yu, HE Yi-Sha, WEI De-Hui, XU Xiao-Lin

2020, 32(6):  640. 

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Objective　To evaluate the effectiveness of Oncomelania snails control following the implementation of integrated schistosomiasis control measures in river channels connecting the Yangtze River in endemic areas of Nanjing City. Methods　The river channels connecting the Yangtze River with snails in Nanjing City were selected as the study pilots. The integrated schistosomiasis control measures implemented in the study pilots were investigated by means of retrospective analyses and field surveys from 1998 to 2019, and the effectiveness of snail control was evaluated. Results　Integrated control measures with emphases on environmental improvements including water resource projects for schistosomiasis control were implemented in the study pilots during the period from 1998 to 2019, including river bank concretion with 84.51 km in length, marshland cutting and dredging with 50.41 km in length, building 2 sluices and 3 overflow dams, digging one floodway and snail control with chemical treatment that covered an area of 3 370.80 hm2. No Schistosoma japonicum infection had been detected in snails since the completion of the integrated control measures. In addition, snails had been eliminated in 6 river channels connecting the Yangtze River until 2019, with the snail habitats reducing from 214.33 hm2 to 52.22 hm2 in 10 river channels connecting the Yangtze River and the snail density reducing to below 0.1 snails/0.1 m2 in snail?breeding river channels connecting the Yangtze River. Conclusions　 The integrated schistosomiasis control measures with emphases on environmental improvements may effectively control snail breeding and spread in rivers connecting the Yangtze River in endemic areas of schistosomiasis; however, the maintenance of the project and snail surveillance and control should be intensified following the completion of the integrated schistosomiasis control measures.

Epidemic situation of malaria in Lishui City from 2013 to 2018

HUANG Xiao-Meng, YE Ling, YU Yang, MEI Jian-Hua

2020, 32(6):  643. 

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Objective　To analyze the epidemic situation and epidemiological characteristics of malaria in Lishui City from 2013 to 2018, so as to provide the evidence for formulating the malaria control strategy. Methods　The data pertaining malaria cases in Lishui City from 2013 to 2018 were captured from National Notifiable Communicable Disease Reporting System and the Information System for Parasitic Diseases Control and Prevention, and the epidemiological features of malaria cases were analyzed. Results　A total of 119 malaria cases were reported in Lishui City from 2013 to 2018, including 101 cases with falciparum malaria (84.87%), 6 cases with vivax malaria (5.04%), 8 cases with ovale malaria (6.72%), and 4 cases with mixed infection (3.36%). Among the 119 cases, there were one local case with blood transfusion?induced malaria and 118 cases with overseas imported malaria. There were 98.32% of the imported malaria cases acquiring infection in African countries, and most cases were reported in Qingtian County (60.50%) and Liandu District (22.69%). In addition, 86.55% of the malaria cases were detected in individuals at ages of 20 to 50 years, and most cases were found in oversea workers (52.94%) and businessmen (38.65%). Conclusion　Most of the malaria cases in Lishui City are imported from Africa, and the monitoring and health education pertaining to malaria control knowledge requires to be intensified among high?risk populations.

Endemic situation of schistosomiasis in national surveillance sites of Zhenjiang City from 2015 to 2019

LI Sha-Sha, WANG Lin, LI Ai-Hua, ZHANG Wan-Jun

2020, 32(6):  646. 

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Objective　To analyze the endemic situation of schistosomiasis in national surveillance sites of Zhenjiang City from 2015 to 2019, so as to provide the scientific basis for the consolidation of schistosomiasis control achievements and timely treatment of risk factors. Methods　A total of 7 national schistosomiasis surveillance sites were assigned in Zhenjiang City from 2015 to 2019. According to the National Scheme for Schistosomiasis Surveillance (2014 version), Schistosoma japonicum infections were monitored in local residents, floating populations and livestock, and snail habitats were surveyed in Zhenjiang City from 2015 to 2019. The results of schistosomaisis surveillance in Zhenjiang City from 2015 to 2019 were analyzed. Results 　There were 15 848 and 7 779 person?times of local residents and floating populations receiving serological screening of schistosomiasis in 7 national surveillance sites of Zhenjiang City from 2015 to 2019, and the seroprevalence rates were 0.95% to 1.75% and 0.14% to 0.91% among local residents and floating populations, respectively; however, no egg?positives were identified. A total of 1 885 herd?times of livestock were detected, and no egg?positives were found. During the 5?year period, snail survey was conducted in snail habitats and suspected snail habitats covering 3 333.79 hm2, and there were 108.71 hm2 snail habitats identified, including 50.97 hm2 re?emerging snail habitats. The density of living snails was 0.007 to 0.125 snails/0.1 m2 from 2015 to 2019, which showed a trend for a rise year by year (χ2 = 2 732.626, P < 0.01); however, no S. japonicum infections were detected in snails. Conclusions　The endemic situation of schistosomiasis has been maintained at a low level in Zhenjiang City, and schistosomiasis control achievements are consolidated. However, snails are widely distributed in the city, and there are still risk factors associated with schistosomiasis transmission. Further integrated interventions require to be reinforced to timely manage the risk of transmission of schistosomiasis and promote the progress towards elimination of schistosomiasis.

Advances in the research on the interaction between human parasites and gut microbiota

ZHU Yuan-Jie, XU Zhi-Peng, JI Min-Jun

2020, 32(6):  649. 

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Human parasites may interact with the microbiome parasitizing in human and mammalian intestines. The interplay between intestinal parasites and gut microbiota and its potential impacts have been widely reported; however, some parasites that do not parasitize in intestines may also affect the characteristic of gut microbiota. Hereby, we review the advances in the research on the impacts of parasites inside and outside of human intestines on the gut microbiota.

Progress of researches on the interaction between parasitic infections and host cell autophagy

2020, 32(6):  654. 

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Autophagy, a conserved intracellular degradation system, is a specific life phenomenon in eukaryocytes. Autophagy is widely accepted as a pathway that double?membrane autophagosomes envelop and sequester intracellular cytoplasmic components and then fuse with lysosomes to form autolysosomes, which degrade their contents to regenerate nutrients. Autophagy may be triggered by starvation and a diverse range of pathogens, including parasites. Following infection with intracellular parasites, host cells may eliminate parasites by autophagy. However, parasites may develop self?defense mechanisms, and promote the self?growth and ?development by host cell autophagy. This review describes the advances in the interplay between parasitic infections and host cell autophagy. Understanding autophagy is of great significance for the management of parasitic infections and the development of antiparasitic drugs.

Progress of researches on the use of ultrasound in the diagnosis and treatment of hepatic alveolar echinococcosis

MENG Qing-Yang, PENG Jie, MA Shu-Mei, FAN Hai-Ning

2020, 32(6):  657. 

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The patients with hepatic alveolar echinococcosis have unapparent early symptoms due to invasive and slow growth, and the disease is usually at an advanced stage upon diagnosis, which has a poor prognosis. Early diagnosis of hepatic alveolar echinococcosis is therefore of great importance. The advances in the ultrasound techniques continues to improve the accuracy for the diagnosis of hepatic alveolar echinococcosis, and ultrasound plays a critical role in the treatment and assessment of therapeutic efficacy for hepatic alveolar echinococcosis. This paper mainly reviews the application of ultrasound in the diagnosis and treatment of hepatic alveolar echinococcosis.

Appendiceal schistosomiasis complicated by low-grade appendiceal mucinous neoplasm: a report of two cases

TANG Wei, WANG Peng

2020, 32(6):  661. 

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This report presents two cases with appendiceal schistosomiasis complicated by low?grade appendiceal mucinous neoplasm.