Exchange bias effect in polycrystalline Bi0.5Sr0.5Fe0.5Cr0.5O3 bulk

Bulk Bi_0.5Sr_0.5Fe_0.5Cr_0.5O₃ (BSFCO) is a new compound comprising the R3c structure. The structural, magnetic property and exchange bias (EB) details are investigated. The material was in the super-paramagnetic (SP) state at room temperature. Exchange bias usually occurs at the boundary between different magnetic states after field cooling (H_FC) acts on the sample. Here the result shows that changing H_FC from 1 to 6 T reduces the H_EB value by 16% at 2 K at the same time. Meanwhile, H_EB diminishes as the ferromagnetic layer thickness increases. The variation of (the thickness of ferromagnetic layer) t_FM with the change of H_FC leads to the tuning of H_EB by H_FC in BSFCO bulk. These effects are obviously different from the phenomenon seen in other oxide types.

[Schistosomiasis control in China from 2012 to 2021: progress and challenges]

Schistosomiasis has been endemic in China for more than 2 000 years, which causes huge morbidity, social and economic burdens. Guided by the national specific strategic programs and criteria for schistosomiasis, tremendous achievements have been gained for schistosomiasis elimination in China. This paper reviews the progress of schistosomiasis control and endemic status of schistosomiasis in China during the period from 2012 to 2021, analyzes the challenges to achieve the goal of schistosomiasis elimination in China by 2030, and proposes suggestions for future schistosomiasis control programs.

[Prevalence of mountain-zoonotic type visceral leishmaniasis in Yangquan City of Shanxi Province from 2015 to 2020]

OBJECTIVE

To investigate the prevalence of mountain-type zoonotic visceral leishmaniasis (MT-ZVL) in Yangquan City, Shanxi Province from 2015 to 2020, so as to provide the scientific evidence for formulating the MT-ZVL control strategy.

METHODS

The epidemiological data pertaining to MT-ZVL cases in Yangquan City from 2015 to 2020 were collected and descriptively analyzed. A Joinpoint regression model was created to analyze the trend in the MT-ZVL incidence in Yangquan City from 2015 to 2020 using annual percent change (APC). The sandflies surveillance data and the prevalence of Leishmania infections in dogs were collected in Yangquan City in 2020, and the regional distribution of sandflies density and sero-prevalence of Leishmania infections in dogs were calculated. In addition, the associations of sandflies density and sero-prevalence of Leishmania infections in dogs with the incidence of human MT-ZVL were examined using the linear correlation analysis.

RESULTS

A total of 162 MT-ZVL cases were reported in Yangquan City, Shanxi Province from 2015 to 2020, with annual mean incidence of 1.9/10⁵, and there were 4, 7, 16, 27, 33 cases and 75 cases with MT-ZVL reported from 2015 to 2020, appearing a tendency towards a rapid rise (APC = 72.79%, t = 11.10, P < 0.01). MT-ZVL cases were reported across the five counties (districts) of Yangquan City, and the cases predominantly occurred in Jiaoqu District (35.2%, 57/162) and Pingding County (33.3%, 54/162). MT-ZVL cases were predominantly detected in residents at ages of 15 years and older (71.6%, 116/162) and at ages of 0 to 2 years (22.2%, 36/162), with farmers (37.4%, 61/162) and diaspora children (24.5%, 40/162) as predominant occupations. The mean density of Phlebotomus chinensis was 6.3 sandflies per trap per night in Yangquan City from during the period from May to September, 2020, with the highest density observed in Jiaoqu District (12.6 sandflies per trap per night) and the lowest in Yuxian County (1.1 sandflies per trap per night), and there was a region-specific mean density of Ph. chinensis in Yangquan City (H = 17.282, P < 0.01). The sero-prevalence of serum anti-Leishmania antibody was 7.4% (2 996/40 573) in domestic dogs in Yangquan City, with the highest sero-prevalence seen in Jiaoqu District (16.6%, 1 444/8 677), and the lowest in Yuxian County (2.3%, 266/11 501), and there was a region-specific sero-prevalence rate of anti-Leishmania antibody in domestic dogs in Yangquan City (χ² = 1 753.74, P < 0.01). The sero-prevalence of anti-Leishmania antibody was significantly higher in stray dogs (20.0%, 159/794) than in domestic dogs (χ² = 176.63, P < 0.01). In addition, there were significant associations among the sandflies density, sero-prevalence of anti-Leishmania antibody in domestic dogs and the incidence of human MT-ZVL (r = 0.832 to 0.870, all P values < 0.05).

CONCLUSIONS

The prevalence of MT-ZVL appeared a tendency towards a rapid rise in Yangquan City from 2015 to 2020, and systematic interventions are urgently needed for MT-ZVL control.

[Neurocognitive impairment and characteristics of neurocognitive performance among people with HIV on antiretroviral treatment]

Objective: Using two measuring tools to examine the prevalence and correlates of neurocognitive impairment (NCI) as well as characteristics of neurocognitive performance among people with HIV (PWH) on antiretroviral treatment (ART). Methods: A total of 2 250 treated PWH from the Comparative HIV and Aging Research in Taizhou (CHART) were recruited in Taizhou, Zhejiang province. The Chinese version of the Mini-mental State Examination (MMSE) and the International HIV Dementia Scale (IHDS) were used to evaluate their neurocognitive performance. Cluster analysis was conducted on the seven cognitive domains in the scale. Results: Among 2 250 treated PWH, 48.0% (1 080/2 250) were aged 45 to 89, 79.2% (1 782/2 250) were male, and 37.8% (852/2 250) had primary school education or below. The prevalence of neurocognitive impairment judged by MMSE and IHDS among HIV-infected people was 14.3% (321/2 250) and 31.8% (716/2 250), respectively. Aged 60 to 89 (aOR=2.63, 95%CI:1.52-4.56), depressive symptoms (aOR=5.58, 95%CI:4.20-7.40) and treatment with EFV (aOR=2.86, 95%CI:1.89-4.34) were main risk factors of NCI diagnosed by MMSE. Male (aOR=0.71, 95%CI:0.51-1.00), overweight (aOR=0.63, 95%CI:0.44-0.89), and high education level (aOR=0.11, 95%CI:0.05-0.25) were protective factors of NCI diagnosed by MMSE. Aged 60 to 89 (aOR=3.10, 95%CI:2.09-4.59), depressive symptoms (aOR=1.78, 95%CI:1.44-2.20) and treatment with EFV (aOR=1.79, 95%CI:1.41-2.29) were risk factors of NCI diagnosed by IHDS. Male (aOR=0.75, 95%CI:0.58-0.97), underweight (aOR=0.67, 95%CI:0.47-0.96), baseline CD4⁺ T lymphocyte (CD4) counts ≥350 cells/μl (aOR=0.69, 95%CI:0.53-0.91) and high education level (aOR=0.23, 95%CI:0.14-0.39) were protective factors of NCI diagnosed by IHDS. The neurocognitive performance of HIV-infected people can be divided into four main types. Among four types, age, gender, education level, alcohol drinking, depressive symptoms, waist-to-hip ratio, hypertension, diabetes, baseline CD4 counts and treatment with EFV were different statistically (all P<0.05). Conclusions: There are four main types of neurocognitive performance in treated PWH. The prevalence of NCI is high among this population, underscoring the need for tailored prevention and intervention.

[Measurement of morphological features of Oncomelania hupensis shells in Yunnan Province]

OBJECTIVE

To investigate the morphological variation of Oncomelania hupensis shells in Yunnan Province, so as to provide insights into the understanding of O. hupensis genetic evolution and control.

METHODS

According to the O. hupensis density, geographical location, altitude, water system and environmental type, 12 administrative villages were sampled from 10 schistosomiasis-endemic counties (districts) in 3 prefectures (cities) of Yunnan Province as snail collection sites. From December 2021 to January 2022, about 200 snails were collected from each collection site, among which thirty adult snails (6 to 7 spirals) were randomly selected from each site, and the 11 morphological indexes of snail shells were measured and subjected to cluster analysis and principal component analysis.

RESULTS

Of O. hupensis snails from 12 localities of Yunnan Province, the longest shell (7.33 mm) was detected in snails from Yongle Village, Eryuan County, with the shortest (4.68 mm) in Dongyuan Village, Gucheng District, and the largest angle of apex (59.47°) was measured in snails from Caizhuang Village, Midu County, with the smallest (41.40°) in Qiandian Village, Eryuan County. The mean coefficient of variation was 9.075% among O. hupensis snails from 12 localities of Yunnan Province, with the largest coefficient of variation seen in the thickness of the labra brim (29.809%). Among O. hupensis snails from 12 localities of Yunnan Province, the mean Euclidean distance was 2.26, with the shortest Euclidean distance seen between O. hupensis snails from Qiandian Village of Eryuan County and Wuxing Village of Dali City (0.26), and the largest found between O. hupensis snails from Caizhuang Village of Midu County and Cangling Village of Chuxiong County (8.17). Cluster analysis and principal component analysis classified O. hupensis snails from 12 localities of Yunnan Province into three categories, including the O. hupensis snail samples from Caizhuang Village of Midu County, O. hupensis snail samples from Cangling Village of Chuxiong County, and O. hupensis snail samples from Qiandian Village of Eryuan County, Wuxing Village of Dali City, Yangwu Village of Yongsheng County, Xiaoqiao Village of Xiangyun County, Yongle Village of Eryuan County, Xiaocen Village of Dali City, Anding Village of Nanjian County, Dongyuan Village of Gucheng District, Lianyi Village of Heqing County, and Dianzhong Village of Weishan County. The variations in these three categories of snail samples were mainly measured in the principal component 2 related to the angle of apex and the thickness of the labra brim.

CONCLUSIONS

The variations in the Euclidean distance and morphological features of shells of O. hupensis from 12 localities of Yunnan Province gradually rise with the decrease in the latitude of the collection sites. The angle of apex is an indicator for the growth of O. hupensis whorl.

[Progress of schistosomiasis control in People's Republic of China in 2021]

This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites in the People's Republic of China at a national level in 2021. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2021. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2021, with 27 571 endemic villages covering 73 250 600 people at risk of infections. Among the 451 endemic counties (cities, districts), 75.17% (339/451), 22.17% (100/451) and 2.66% (12/451) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2021, 29 037 cases with advanced schistosomiasis were documented in China. In 2021, 4 405 056 individuals received serological tests and 72 937 were sero-positive. A total of 220 629 individuals received stool examinations and 3 were positive. In 2021, snail survey was performed in 19 291 endemic villages in China and Oncomelania snails were found in 7 026 villages, accounting for 36.42% of all surveyed villages, with 12 villages identified with emerging snail habitats. Snail survey was performed at an area of 686 574.46 hm² and 191 159.91 hm² snail habitats were found, including 1 063.08 hm² emerging snail habitats and 5 113.87 hm² reemerging snail habitats. In 2021, 525 878 bovines were raised in the schistosomiasis endemic areas of China, and 115 437 received serological examinations, with 231 positives detected. Among the 128 719 bovines received stool examinations, no positives were identified. In 2021, there were 19 927 schistosomiasis patients receiving praziquantel chemotherapy, and 729 113 person-time individuals and 256 913 herd-time bovines were given expanded chemotherapy. In 2021, snail control with chemicals was performed in 117 372.74 hm² snail habitats, and the actual area of chemical treatment was 65 640.50 hm², while environmental improvements were performed in snail habitats covering an area of 1 244.25 hm². Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2021, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remained at a low level in China in 2021; however, the progress towards schistosomiasis elimination was slowed and the areas of snail habitats rebounded mildly. Strengthening researches on snail diffusion and control, and improving schistosomiasis surveillance and forecast are recommended to prevent reemerging schistosomiasis.

[Taxonomic rank of human parasites]

Biological category is effective to indicate the evolution of organism populations between past and present. Conventional taxonomy of human parasites mainly depends on important morphological features, which suffers from a problem of categorizing related-genera species with similar morphological characteristics. With recent advances in molecular biological technologies, the effective applications of mitochondrial and ribosomal biomarkers and sequencing greatly improve the development of the taxonomic rank of human parasites. Worldwide, the classification of human parasites have been continuously revised and improved. Hereby, we re-categorize parasitic Protozoa, Trematoda, Cestoda and Nematoda, so as to provide insights into the researches on molecular systematics and genetic evolution of human parasites.

[Sharing the WHO guideline on control and elimination of human schistosomiasis to achieve the goal of schistosomiasis elimination in China]

Currently, the national schistosomiasis control program of China is moving from transmission interruption to elimination, and there are multiple challenges during the stage moving towards the progression of schistosomiasis elimination, including a high difficulty in shrinking snail-infested areas, unstable achievements for infectious source control, imperfect surveillance system and a reduction in schistosomiasis control and administration. Based on the core suggestions proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, recommendations on schistosomiasis surveillance system building, development of novel diagnostics, adjustment of the schistosomiasis control strategy and maintaining and improvements of the schistosomiasis control capability are proposed for the national schistosomiasis control program of China in the new era according to the actual status of schistosomiasis control in China. Formulation of the national schistosomiasis control strategy and goal from One Health perspective, verification of transmission interruption and elimination of schistosomiasis, precision implementation of schistosomiasis control interventions with adaptations to local circumstances, development and application of highly sensitive and specific diagnostics are recommended for elimination of schistosomiasis in China. In addition, the implementation of the 2022 WHO guideline on control and elimination of human schistosomiasis may guide the elimination of schistosomiasis in China.

[Analysis of the new WHO guideline to accelerate the progress towards elimination of schistosomiasis in China]

On February 2022, WHO released the evidence-based guideline on control and elimination of human schistosomiasis, with aims to guide the elimination of schistosomiasis as a public health problem in disease-endemic countries by 2030 and promote the interruption of schistosomiasis transmission across the world. Based on the One Health concept, six evidence-based recommendations were proposed in this guideline. This article aims to analyze the feasibility of key aspects of this guideline in Chinese national schistosomiasis control program and illustrate the significance to guide the future actions for Chinese national schistosomiasis control program. Currently, the One Health concept has been embodied in the Chinese national schistosomiasis control program. Based on this new WHO guideline, the following recommendations are proposed for the national schistosomiasis control program of China: (1) improving the systematic framework building, facilitating the agreement of the cross-sectoral consensus, and building a high-level leadership group; (2) optimizing the current human and livestock treatments in the national schistosomiasis control program of China; (3) developing highly sensitive and specific diagnostics and the framework for verifying elimination of schistosomiasis; (4) accelerating the progress towards elimination of schistosomiasis and other parasitic diseases through integrating the national control programs for other parasitic diseases.

[Decoding the evolution of preventive chemotherapy schemes for schistosomiasis in China to improve the precise implementation of the WHO guideline on control and elimination of human schistosomiasis]

Preventive chemotherapy is one of the pivotal interventions for the control and elimination of schistosomiasis, which is effective to reduce the morbidity and prevalence of schistosomiasis. In order to promote the United Nations' sustainable development goals and the targets set for schistosomiasis control in the Ending the neglect to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021-2030, WHO released the guideline on control and elimination of human schistosomiasis in 2022, with major evidence-based updates of the current preventive chemotherapy strategy for schistosomiasis. In China where great success has been achieved in schistosomiasis control, the preventive chemotherapy strategy for schistosomiasis has been updated several times during the past seven decades. This article reviews the evolution of the WHO guidelines on preventive chemotherapy and Chinese national preventive chemotherapy schemes, compares the current Chinese national preventive chemotherapy scheme and the recommendations for preventive chemotherapy proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, and proposes recommendations for preventive chemotherapy during the future implementation of the 2022 WHO guideline, so as to provide insights into schistosomiasis control among public health professionals engaging in healthcare foreign aid.

[Contribution to global implementation of WHO guideline on control and elimination of human schistosomiasis by learning successful experiences from the national schistosomiasis control program in China]

Schistosomiasis is a parasitic disease that seriously hinders socioeconomic developments and threatens public health security. To achieve the global elimination of schistosomiasis as a public health problem by 2030, WHO released the guideline on control and elimination of human schistosomiasis on February, 2022, with aims to provide evidence-based recommendations for schistosomiasis morbidity control, elimination of schistosomiasis as a public health problem, and ultimate interruption of schistosomiasis transmission in disease-endemic countries. Following concerted efforts for decades, great achievements have been obtained for schistosomiasis control in China where the disease was historically highly prevalent, and the country is moving towards schistosomiasis elimination. This article reviews the successful experiences from the national schistosmiasis control program in China, and summarizes their contributions to the formulation and implementation of the WHO guideline on control and elimination of human schistosomiasis. With the progress of the "Belt and Road" initiative, the world is looking forward to more China's solutions on schistosomiasis control.

[Prediction of trends for fine-scale spread of Oncomelania hupensis in Shanghai Municipality based on supervised machine learning models]

OBJECTIVE

To predict the trends for fine-scale spread of Oncomelania hupensis based on supervised machine learning models in Shanghai Municipality, so as to provide insights into precision O. hupensis snail control.

METHODS

Based on 2016 O. hupensis snail survey data in Shanghai Municipality and climatic, geographical, vegetation and socioeconomic data relating to O. hupensis snail distribution, seven supervised machine learning models were created to predict the risk of snail spread in Shanghai, including decision tree, random forest, generalized boosted model, support vector machine, naive Bayes, k-nearest neighbor and C5.0. The performance of seven models for predicting snail spread was evaluated with the area under the receiver operating characteristic curve (AUC), F1-score and accuracy, and optimal models were selected to identify the environmental variables affecting snail spread and predict the areas at risk of snail spread in Shanghai Municipality.

RESULTS

Seven supervised machine learning models were successfully created to predict the risk of snail spread in Shanghai Municipality, and random forest (AUC = 0.901, F1-score = 0.840, ACC = 0.797) and generalized boosted model (AUC= 0.889, F1-score = 0.869, ACC = 0.835) showed higher predictive performance than other models. Random forest analysis showed that the three most important climatic variables contributing to snail spread in Shanghai included aridity (11.87%), ≥ 0 °C annual accumulated temperature (10.19%), moisture index (10.18%) and average annual precipitation (9.86%), the two most important vegetation variables included the vegetation index of the first quarter (8.30%) and vegetation index of the second quarter (7.69%). Snails were more likely to spread at aridity of < 0.87, ≥ 0 °C annual accumulated temperature of 5 550 to 5 675 °C, moisture index of > 39% and average annual precipitation of > 1 180 mm, and with the vegetation index of the first quarter of > 0.4 and the vegetation index of the first quarter of > 0.6. According to the water resource developments and township administrative maps, the areas at risk of snail spread were mainly predicted in 10 townships/subdistricts, covering the Xipian, Dongpian and Tainan sections of southern Shanghai.

CONCLUSIONS

Supervised machine learning models are effective to predict the risk of fine-scale O. hupensis snail spread and identify the environmental determinants relating to snail spread. The areas at risk of O. hupensis snail spread are mainly located in southwestern Songjiang District, northwestern Jinshan District and southeastern Qingpu District of Shanghai Municipality.

[Molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate in hilly schistosomiasis-endemic regions]

OBJECTIVE

To evaluate the molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate (WPPS) against Oncomelania snails in hilly schistosomiasis-endemic regions and test its toxicity to fish.

METHODS

In October 2020, a snail-infested setting which had been cleared was selected in Nanjian County, Yunnan Province and divided into several blocks, and the natural snail mortality was estimated. 25% WPPS was prepared into solutions at concentrations of 1 and 2 g/L, and 25% wettable powder of niclosamide ethanolamine salt (WPNES) was prepared into solutions at a concentration of 2 g/L. The different concentrations of drugs were sprayed evenly, and the same amount of water was used as blank control. Snails were surveyed using the systematic sampling method 1, 3 and 7 days post-treatment, and snail survival was observed. A fish pond was selected in Nanjian County, and 2 kg 25% WPPS was evenly sprayed on the water surface to allow the effective concentration of 20 g/L. Fish mortality was estimated 8, 24, 48 and 72 h post-treatment.

RESULTS

One-day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 97.99%, 97.99% and 94.11% adjusted snail mortality rates (χ² = 3.509 and 3.509, both P values > 0.05), and the adjusted snail mortality was all 100% 3 d post-treatment with 1 and 2 g/L WPPS and 2 g/L WPNES, while 7-day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 91.75%, 86.57% and 57.76% adjusted snail mortality rates (χ² = 14.893 and 42.284, both P values < 0.05). Treatment with 2 g/L WPPS for 72 h resulted in a 0.67% cumulative mortality rate of fish.

CONCLUSIONS

25% WPPS is effective for snail control and highly safe for fish, which is feasible for use in hilly schistosomiasis-endemic regions.

[Current status and challenges for taeniasis and cysticercosis control in China]

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.

[Endemic status of schistosomiasis in People's Republic of China in 2020]

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2020, and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2020. A total of 450 counties (cites, districts) were found to be endemic for schistosomiasis in China, with 28 376 endemic villages covering 71 370 400 people at risk of infections. Among the 450 endemic counties (cities, districts), 74.89% (337/450), 21.87% (98/450) and 3.33% (15/450) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2020, 29 517 cases with advanced schistosomiasis were documented in China. In 2020, 11 117 655 individuals received inquiry examinations and 1 798 580 were positive; 5 263 082 individuals received serological tests and 83 179 were sero-positive. A total of 273 712 individuals received stool examinations and 3 were positive, including one case of acute schistosomiasis. In 2020, snail survey was performed in 19 733 endemic villages in China and Oncomelania snails were found in 7 309 villages, accounting for 37.04% of all surveyed villages, with 15 villages identified with emerging snail habitats. Snail survey covered an area of 736 984.13 hm² and 206 125.22 hm² snail habitats were found, including 1 174.67 hm² emerging snail habitats and 1.96 hm² habitats with infected snails. In 2020, 544 424 bovines were raised in the schistosomiasis-endemic areas of China, and 147 887 received serological examinations, with 326 positives detected, while 130 673 bovines received stool examinations, with no positives identified. In 2020, there were 19 214 patients with schistosomiasis receiving praziquantel chemotherapy, and 964 103 person-time individuals and 266 280 herd-time bovines were given expanded chemotherapy. In 2020, molluscicide treatment was performed in 136 141.92 hm² snail habitats, and the actual area of chemical treatment was 71 980.22 hm², while environmental improvements were performed in snail habitats covering an area of 1 464.03 hm². Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2020, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remains at a low level in China and the goal of the National Thirteenth Five-Year Plan for Schistosomiasis Control was achieved as scheduled; however, the endemic situation of schistosomiasis rebounded in local areas. Precision schistosomiasis control and intensified monitoring of the endemic situation and transmission risk of schistosomiasis are required to be performed to facilitate the progress towards elimination of schistosomiasis steadily.

[Analysis on epidemiological characteristics of current advanced schistosomiasis cases in China based on the Epidemiological Dynamic Data Collection Platform (EDDC)]

OBJECTIVE

To investigate the epidemiological characteristics of current advanced schistosomiasis cases in China, so as to provide the scientific evidence for the precision management and medical care of advanced schistosomiasis.

METHODS

The baseline data pertaining to the current advanced schistosomiasis cases in China were collected from the Epidemiological Dynamic Data Collection Platform (EDDC) operated by the Chinese Center for Disease Control and Prevention. The demographic characteristics, population and regional distribution and medical care of advanced schistosomiasis cases were analyzed with a descriptive method.

RESULTS

A total of 31 889 cases with advanced schistosomiasis were reported in China by the end of June, 2019, and these cases were mainly identified in Hubei Province (7 737 cases) followed by in Jiangxi Province (7 256 cases), Hunan Province (5 615 cases), Anhui Province (5 236 cases) and Jiangsu Province (2 908 cases), accounting for 90.2% (28 752/31 889) of total cases in China. The current advanced schistosomiasis cases had a male/female ratio of 1.5∶1, and a mean age of (67.0 ± 11.2) years, with 92.6% (29 521/31 889) detected in individuals at ages of over 50 years. There were 97.6% (31 109/31 889) of the cases with an educational level of junior high school and lower, and 95.2% (30 359/31 889) with an occupation of farmers. Ascites (72.6%, 23 164/31 889) and splenomegaly types (26.3%, 8 386/31 889) were predominant in current advanced schistosomiasis cases in China, and there was a significant difference in the constituent ratio of disease types among current advanced schistosomiasis cases with different age groups (χ² = 362.31, P < 0.01), with the ascites type as the predominant type of advanced schistosomiasis. Among the current advanced schistosomiasis cases, 88.9% (28 358/31 889) and 18.7% (5 973/31 889) had received medical treatment and surgical treatment, respectively.

CONCLUSIONS

The current advanced schistosomiasis cases are predominantly reported in five marshland and lake endemic provinces of China where schistosomiasis is not eliminated, and are mostly categorized as the ascites and megalosplenia types, with minor differences seen in gender and disease-type distributions. Precision medical care should be reinforced according to the epidemiological features of the current advanced schistosomiasis cases, and early screening and standard management and follow-up is required.

[National surveillance of schistosomiasis morbidity in China, 2015-2019]

OBJECTIVE

To understand the morbidity due to Schistosoma japonicum in national schistosomiasis surveillance sites of China from 2015 to 2019, so as to provide insights into schistosomiasis control and elimination and provide the scientific evidence for formulating the new scheme for schistosomiasis surveillance in China.

METHODS

According to the requirements of National Scheme for Schistosomiasis Surveillance in China (2014 Edition), national schistosomiasis surveillance sites were assigned in all schistosomiasis-endemic counties (cities, districts) and the potential endemic counties (cities, districts) in the Three Gorges Reservoir areas, and S. japonicum infections were monitored in local residents, mobile populations and livestock according to different epidemic types. The sero-prevalence of S. japonicum infections, adjusted prevalence of human S. japonicum infections, characteristics of egg-positive individuals and prevalence of S. japonicum infections livestock were analyzed.

RESULTS

S. japonicum infections were monitored in 453 schistosomiasis-endemic counties (cities, districts) from 13 provinces (municipalities, autonomous regions) and 4 potential endemic counties (cities, districts) from the Three Gorges Reservoir areas in China from 2015 to 2019. During the 5-year period from 2015 to 2019, the sero-prevalence of S. japonicum infections reduced from 3.35% to 1.63% among local residents and from 1.15% to 0.75% among mobile populations, while the adjusted prevalence of infections reduced from 0.05% to 0 among local residents and from 0.20% to 0.001 03% among mobile populations. There were significant differences in the sero-prevalence of S. japonicum infections among local residents and mobile populations in terms of province, occupation and age (all P values < 0.05). A total of 132 egg-positives were identified during the 5-year period, including 97 local residents (inter-quartile range for ages, 47 to 61 years), and 35 mobile populations (inter-quartile range for ages, 26 to 48 years), and there was a significant difference in the age distribution between local residents and mobile populations (P < 0.05). There were totally 6 bovines (5 in 2015 and 1 in 2016) identified with S. japonicum infections in national schistosomiasis surveillance sites of China, with no S. japonicum infections detected in bovines from 2017 to 2019.

CONCLUSIONS

The prevalence of schistosomiasis is very low in China. Further surveillance including more mobile surveillance sites seems justified to identify the risk of schistosomiasis as soon as possible and interrupt the transmission route, so as to facilitate the elimination of schistosomiasis in China.

[National surveillance of Oncomelania hupensis in China, 2015-2019]

OBJECTIVE

To analyze the monitoring data of Oncomelania hupensis in the national schistosomiasis surveillance sites of China from 2015 to 2019, so as to understand the changes of Oncomelania snail status in the schistosomiasis-endemic areas of China and to provide the scientific evidence for Oncomelania snail control.

METHODS

According to the requirements of National Scheme for Schistosomiasis Surveillance in China (2014 Edition), national schistosomiasis surveillance sites were assigned in all schistosomiasis-endemic counties (cities, districts) and the potential endemic counties (cities, districts) in the Three Gorges Reservoir areas, and Oncomelania snail status was monitored according to different epidemic types. In endemic areas, Oncomelania snail survey was performed by means of systematic sampling and environmental sampling, and the occurrence of frames with Oncomelania snails and the prevalence of Schistosoma japonicum infections in Oncomelania snails were calculated, while in potential endemic areas, the risk of imported Oncomelania snails and Oncomelania snails in floating debris were monitored.

RESULTS

Oncomelania snail survey was performed covering an area of 116 834.16 hm² in the national schistosomiasis surveillance of China from 2015 to 2019, with 35 007.62 hm² Oncomelania snail habitats identified. A total of 6 908 292 frames were surveyed during the 5-year period, and there were 364 555 frames detected with Oncomelania snails, with a 5.28% mean occurrence of frames with Oncomelania snails. Among 997 508 living Oncomelania snails captured, no S. japonicum infections were detected, and loop-mediated isothermal amplification (LAMP) assay detected 18 positive mixed Oncomelania snail samples. During the period from 2015 to 2019, 147.20 hm² emerging Oncomelania snail habitats were identified, with an overall tendency towards a rise seen in the proportion of emerging Oncomelania snail habitats in plain regions with waterway networks (0.12% to 92.00%), a tendency towards a rise followed by decline seen in marshland and lake regions (0 to 96.72%), and a large fluctuation in hilly regions (0 to 88.49%). A total of 831.10 hm² re-emerging Oncomelania snail habitats were found in the national schistosomiasis surveillance sites of China from 2015 to 2019, with an overall tendency towards a rise seen in the proportion of re-emerging Oncomelania snail habitats in marshland and lake regions (16.05% to 79.66%), an overall tendency towards a decline seen in hilly regions (19.25% to 81.00%), and a minor fluctuation in plain regions with waterway networks (1.10% to 10.14%). During the 5-year period from 2015 to 2019, a total of 48 656 kg floating debris were captured in 4 surveillance sites in the Three Gorges Reservoir areas, and 2 204 snails were found, with no Oncomelania snails identified.

CONCLUSIONS

The areas of Oncomelania snail habitats tended to be stable in the national schistosomiasis surveillance sites of China during the period from 2015 to 2019, however, there was a gradual rise in the area of Oncomelania snail habitats year by year, and LAMP assay identified positive Oncomelania snail samples, suggesting Oncomelania snail control is far from optimistic in China.

[Clinico-pathological and follow-up analysis of 5 skeletal muscle single-organ vasculitis cases]

Objectives: To delineate clinico-pathological features, treatment and outcome of skeletal muscle single-organ vasculitis (SM-SOV). Methods: The clinico-pathological characteristic of SM-SOV cases treated over 3 years in China-Japan Friendship Hospital were retrospectively analyzed and the data were compared with the cases from the literature. Results: Five patients (2 women and 3 men) with a median age of 36 years were included in this study. The main clinical manifestations were lower limb myalgia (5/5) and fever (1/5). The most frequent laboratory findings included high erythrocyte sedimentation rate (5/5), high C reactive protein (5/5) and leukocytosis (1/5). No elevated creatine kinase (CK) was found in these cases. Four patients received electromyogram examination and none of them showed myogenic injury. On MRI, hyperintense signals in T₂ weighted image (T₂WI) and/or short TI inversion recovery (STIR) and normal unenhanced T₁ weighted image (T₁WI) of one or several leg muscles was founded in all 5 patients. All muscle specimens showed nongranulomatous vasculitis without myonecrosis affecting small sized artery (5/5) in perimysia (75.0%, 3/4) or both perimysia and fascia (25.0%, 1/4). Corticosteroids (5/5) and immunosuppressants (5/5) were the main agents prescribed. With a median follow-up of 24 months, sustained remission was observed in 3 patients, relapses occurred in 2 patients. Conclusion: SM-SOV should be considered for patients with lower limb myalgia, high inflammatory markers and normal/low CK level. The diagnosis of SM-SOV should be applied when there are both histologic evidence of vasculitis and a minimum of 6 months of follow-up surveillance without evidences suggesting extra-muscular involvement. Corticosteroid combined with immunosuppressant is effective.

[Expert consensus on the strategy and measures to interrupt the transmission of schistosomiasis in China]

Since 2015 when the transmission of schistosomiasis was controlled in China, the country has been moving towards elimination of schistosomiasis, with the surveillance-response as the main interventions for schistosomiasis control. During the period of the 13th Five-Year Plan, the transmission of schistosomiasis had been interrupted in four provinces of Sichuan, Jiangsu, Yunnan and Hubei and the prevalence of schistosomiasis has been at the historically lowest level in China. As a consequence, the goal set in The 13th Five-Year National Schistosomiasis Control Program in China is almost achieved. However, there are multiple challenges during the stage moving towards elimination of schistosomiasis in China, including the widespread distribution of intermediate host snails and complicated snail habitats, many types of sources of Schistosoma japonicum infections and difficulty in management of bovines and sheep, unmet requirements for the current schistosomiasis control program with the currently available tools, and vulnerable control achievements. During the 14th Five-Year period, it is crucial to consolidate the schistosomiasis control achievements and gradually solve the above difficulties, and critical to provide the basis for achieving the ultimate goal of elimination of schistosomiasis in China. Based on the past experiences from the national schistosomiasis control program and the challenges for schistosomiasis elimination in China, an expert consensus has been reached pertaining to the objectives, control strategy and measures for The 14th Five-Year National Schistosomiasis Control Program in China, so as to provide insights in to the development of The 14th Five-Year National Schistosomiasis Control Program in China.

[Key points and research priorities of schistosomiasis control in China during the 14th Five-Year Plan Period]

Schistosomiasis was once endemic in 12 provinces (municipalities, autonomous regions) along and south of the Yangtze River basin, which seriously damages human health and hinders socioeconomic developments in China. Following the concerted efforts for 70 years, remarkable achievements have been gained in the national schistosomiasis control program of China. However, there are still multiple challenges for elimination of schistosomiasis in the country. This paper describes the current status of schistosomiasis and the challenges during the progress towards the elimination of schistosomiasis, and proposes the goals, key points and research priorities of schistosomiasis control in China during the 14th Five-Year Plan Period.

[Endemic status of schistosomiasis in People's Republic of China in 2019]

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 seropositive. 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.

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

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.

CONCLUSIONS

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.

[Assessment of schistosomiasis transmission risk along the Yangtze River basin after the flood disaster in 2020]

OBJECTIVE

To evaluate the impact of the flood disaster on schistosomiasis transmission along the Yangtze River basin in 2020, so as to provide insights into schistosomiasis prevention and control in flood-affected areas.

METHODS

The data pertaining to the endemic situation of schistosomiasis were collected from 5 provinces of Hunan, Hubei, Jiangxi, Anhui and Jiangsu from 2013 to 2019, including Schistosoma japonicum infections in humans and livestock and snail distribution, and the warning water levels and actual water status were collected in water regions locating in these 5 provinces. The cumulative numbers of S. japonicum egg-positive individuals and bovines during the period from 2013 to 2019, the area of snail habitats in 2019 and the water level on July 12, 2020 were estimated at a county level and employed as parameters for classification of schistosomiasis transmission risk. Then, the cumulative value of each risk index was calculated to assess the risk of schistosomiasis transmission risk.

RESULTS

After the flood disaster along the Yangtze River basin in 2020, there were 10, 5 and 9 counties (districts) at high risk of schistosomiasis transmission in 5 provinces of Hunan, Hubei, Jiangxi, Anhui and Jiangsu based on number of egg-positive individuals, number of egg-positive bovines and snail distribution, respectively. Based on comprehensive risk indices, there were 10 (8 in Dongting Lake regions of Hunan Province and 2 in Poyang Lake regions of Jiangxi Province) and 15 counties (districts) (4 in Hubei Province, 7 in Hunan Province and 4 in Jiangxi Province) identified at grades 5 and 4 risk of schistosomiasis transmission.

CONCLUSIONS

Dongting Lake regions and Poyang Lake regions are the most severely flood-affected schistosomiasis-endemic foci of China in 2020, and the flood disaster may facilitate the transmission of schistosomiasis in affected areas. Therefore, schistosomiasis control requires to be intensified after the flood disaster to prevent the rebound of the disease.

[Challenges of schistosomiasis control in China during the coronavirus disease 2019 (COVID-19) epidemic]

OBJECTIVE

To investigate the implementation of schistosomiasis control activities in China during the coronavirus disease 2019 (COVID-19) epidemic, so as to evaluate the impact of COVID-19 epidemic on the national schistosomiasis control program in China.

METHODS

On April 2020, 3 counties (districts) were randomly selected from each of the 12 schistosomiasis-endemic provinces (municipality, autonomous region), and a questionnaire survey was conducted to investigate the implementation of schistosomiasis control activities in these counties (districts) from January to March 2020. Then, the impact of the COVID-19 epidemics on the national schistosomiasis control program of China was evaluated using a comparative analysis approach.

RESULTS

Among the 36 counties (cities, districts) sampled from 12 provinces (municipality, autonomous region), 66.67% were at a high and medium risk of COVID-19 epidemics. The implementation of schistosomiasis control activities assignment, human schistosomiasis examination and treatment, snail control with chemical treatment and health education reduced by 44.26% to 91.56% as compared to 2019 during the same time period, and the schistosomiasis control program was more affected by COVID-19 in transmission-controlled provinces. The gross funds invested into the schistosomiasis control program reduced by 23.39% in relative to the expected, while the total expenditure increased by 41.22%. In addition, all 36 surveyed counties (districts) considered that the COVID-19 epidemic had a short-term impact on the schistosomiasis control program, with the most predominant impact on schistosomiasis control activities assignment, human resources and monitoring of endemic situation of schistosomiasis.

CONCLUSIONS

The COVID-19 epidemics affect the routine schistosomiasis control program across the endemic-foci of China. Policy and financial support should be strengthened to ensure the completion of the schistosomiasis control program.

[Prevalence of soil - borne nematode infections among residents living in urban/town areas of China in 2015]

OBJECTIVE

To understand the prevalence of soil-borne nematode infections among residents living in urban/town areas of China, so as to provide insights into the control and elimination of soil-borne nematodiasis.

METHODS

A total of 5 epidemic areas were classified in China according to the prevalence of human Clonorchis sinensis infections captured from the 2014-2015 national survey on major human parasitic diseases in China, and the total sample size was estimated according to the binomial distribution and Poisson's distribution. Then, the total sample size was allocated proportionally to each province (autonomous region, municipality) of China based on the percentage of residents living in urban and town areas, and the number of survey sites in each province (autonomous region, municipality) was proportionally assigned according to the percentages of residents living in urban and town areas. Then, stratified sampling was performed at county, township and community levels according to the number of sampling sites in each province (autonomous region, municipality), and the survey site (community) was defined as the smallest sampling unit. All permanent residents in the survey sites were selected as the study subjects, and their stool samples were collected for identification and counting of parasite egg using a Kato-Katz technique. The prevalence and intensity of each parasite species were calculated.

RESULTS

From 2014 to 2015, among the 133 231 residents detected in 31 provinces (autonomous regions, municipalities) of China, the overall prevalence of soil-borne nematode infections was 1.23% (1 636/133 231), and the prevalence rates of hookworm, Ascaris lumbricoides and Trichuris trichiura infections were 0.77% (1 032/133 231), 0.32% (426/133 231) and 0.17% (224/133 231), respectively. The highest prevalence of soil-borne nematode infections was seen in Jiangxi (4.03%, 82/2 034) and Chongqing (4.03%, 524/13 012), followed by in Hainan (3.47%, 72/2 075). The prevalence of soilborne nematode infections was 1.07% (662/62 139) in men and 1.37% (974/71 092) in women, and the greatest prevalence was found in residents at ages of 65 to 70 years (2.56%, 219/8 569). With regard to occupations and education levels, herdsmen (2.47%, 2/81) and illiterate residents (3.33%, 226/6 795) were found to have the highest prevalence of soil-borne nematode infections, respectively. In addition, mild infections were predominantly identified in hookworm-, A. lumbricoides- and T. trichiura-infected individuals (all > 90%).

CONCLUSIONS

The overall prevalence of soil-borne nematodiasis remains low in urban and town areas of China; however, human infections are widespread. According to the epidemiological features, health education combined with deworming are recommended to reduce the prevalence of soil-borne nematode infections among residents living in urban and town areas of China.

[Molecular identification of Tricula spp. and the parasitized trematode cercariae in schistosomiasis-endemic areas of Yunnan Province]

OBJECTIVE

To characterize a species of the genus Tricula and parasitized trematodes in schistosomiasis-endemic areas of Yunnan Province using a molecular analysis, so as to understand their taxonomic positions.

METHODS

Tricula spp. and Oncomelania snails were collected from Xiangyun County, Yunnan Province, and cercaria parasitizing snails were observed using crushing followed by microscopy. Cercaria parasitizing Tricula snails at various morphologies were sampled using a shedding method. Genomic DNA was extracted from snail soft tissues and cercariae, and the 16S rRNA, COI, 28S rDNA genes in snails and the ND1 and 28S rDNA genes in cercariae were amplified using a PCR assay and sequenced. The species of Tricula snails and their parasitized trematodes was characterized using sequence alignment and phylogenetic analysis.

RESULTS

Among 382 Tricula snails detected, there were three types of trematode cercariae found, including the non-forked (20.94%, 80/382), double-forked (3.40%, 13/382) and swallow shapes (7.07%, 27/382). Sequence and phylogenetic analyses showed that the 16S rRNA, COI and 28S rDNA gene sequences of this species of Tricula had high homology to those in Delavaya dianchiensis, and were clustered in a branch. Sequencing analysis of the ND1 and 28S rDNA genes revealed that the non-forked cercariae belonged to the family Pleu- rogenidae, the swallow-shaped cercariae belonged to the family Opecoelidae, and the double-forked cercariae belonged to another species of the genus Schistosoma that was different from S. sinensium and S. ovuncatum.

CONCLUSIONS

The species and taxonomy of Triculla spp. and their parasitized trematodes are preliminarily determined in schistosomiasis-endemic areas of Yunnan Province; however, further studies are required to investigate the more definite taxonomy and pathogenicity.

[Strategy for the South-South cooperation on schistosomiasis control under the Belt and Road Initiative]

Following the concerted efforts for nearly 70 years, great successes have been achieved in the national schistosomiasis control programme in China. Currently, the national schistosomiasis control programme in China is facing the challenges to solve the problems during the"final mile"stage towards schistosomiasis elimination, and contribute Chinese experiences, Chinese strategy and Chinese wisdom to the global schistosomiasis control programmes, so as to facilitate the transformation of the joint efforts in the Belt and Road Initiative to a high-quality development, thereby well supporting the activities on global health security. This paper analyzes the current global status of schistosomiasis and the challenges of the global schistosomiasis control programmes, describes the basis for the cooperation on schistosomiasis control among the countries along the Belt and Road Initiative, illustrates the challenges for translation of Chinese experiences and techniques in schistosomiasis control to other diseaseendemic countries, and proposes the patterns and prospects of the South-South cooperation on schistosomiasis control under the Belt and Road Initiative.

[Surveillance and control strategy of imported schistosomiasis mansoni: an expert consensus]

In 1980s, Biomphalaria straminea, an intermediate host of Schistosoma mansoni, was found in Shenzhen City, Guangdong Province, China, and currently, this snail has colonized in Shenzhen City and spread to peripheral cities involving of Dongguan and Huizhou. Since imported cases infected with S. mamoni have been reported from time to time in China, Mainland China is facing the potential risk of transmission of schistosomiasis mansoni. With the deepening of the opening-up policy, notably the implementation of the Belt and Road Initiative, there is an increase in the risk of transmission of schistosomiasis mansoni in Mainland China. Increasing the understanding on schistosomiasis mansoni, improving the awareness toward schistosomiasis mansoni prevention and control, and identifying, reporting and managing imported cases with S. mansoni infection or pathogen carriers, are of particular importance to prevent the development of entire life cycle of S. mansoni and the resultant schistosomiasis mansoni transmission in China. To protect public health, a consensus has been reached pertaining to the surveillance and control strategy of imported schistosomiasis mansoni by Chinese infectious disease experts and parasitologists, with aims to improve the awareness and capability for the diagnosis, treatment and control of imported schistosomiasis mansoni among Chinese disease control and prevention institutions and medical institutions, and decrease and even eliminate the risk of schistosomiasis mansoni transmission in China.

[Endemic status of schistosomiasis in People's Republic of China in 2018]

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2018, and analyzed the data collected from the national schistosomiasis prevention and control system and 453 national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, 5 provinces (municipality and autonomous region), including Shanghai, Zhejiang, Fujian, Guangdong and Guangxi, continued to consolidate the achievements of schistosomiasis elimination, Sichuan Province achieved transmission interruption and 6 provinces of Yunnan, Jiangsu, Hubei, Anhui, Jiangxi and Hunan achieved transmission control by the end of 2018. There were 450 endemic counties (cities, districts) covering 260 million people, specifically including 28 456 endemic villages covering 70.059 7 million people at risk of infection. Among the 450 endemic counties (cities, districts), 58.44% (263/450), 27.56% (124/450) and 14.00% (63/450) reached the criteria of elimination, transmission interruption and transmission control, respectively. By the end of 2018, a total of 29 214 advanced schistosomiasis cases were documented in China. In 2018, a total of 11.127 6 million individuals received inquiry examinations and 2.062 9 million were positive; 7.191 4 million individuals received serological tests and 138.5 thousand of them were positive, 532.2 thousand individuals received stool examinations and 8 were positive in China. In 2018, snail survey was performed in 19 821 endemic villages and Oncomehania snails were found in 7 321 villages, accounting for 36.94% of all surveyed villages, with 3 newly detected villages with snails in China. Snail survey covered an area of 590 241.01 hm² and 168 319.41 hm² snail habitats were found, including emerging snail habitats of 61.28 hm²; however, no infected snails were identified. In 2018, a total of 646 823 bovines were raised in the schistosomiasis endemic areas of China, and 225 258 received serological examinations, with 2 638 positives detected, while 164 803 bovines received stool examinations, with 2 positives identified. In 2018, there were 90 388 patients with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 1 490 594 person-times; there were two bovines with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 352 577 bovine-times; chemical treatment was conducted in an area of 141 660.87 hm², including an actual mollusciciding area of 75 308.26 hm², and environmental improvements were performed in an area of 4 738.37 hm² in China. Data from the 453 national schistosomiasis surveillance sites of China showed that the mean Schistosoma japonicum infection rates were 0.001 5% and zero in humans and bovines in 2018, respectively, and no infected snails were found. The results demonstrate that the endemic situation of schistosomiasis appears a tendency towards a continuous decline in China; however, there is still a risk of schistosomiasis transmission, and challenges remain in achieving the target set in the Thirteenth Five-Year National Plan for Schistosomiasis Control in 2020 in some regions.

[Therapy-related myeloid neoplasms after successful treatment for acute promyelocytic leukemia: a report of four cases and literature review]

目的

探讨急性早幼粒细胞白血病（APL）患者继发治疗相关性髓系肿瘤（t-MN）的临床特点、诊断、治疗及预后。

方法

回顾性分析中国医学科学院血液病医院2012年10月至2019年1月收治的4例APL继发t-MN患者的临床资料，并进行相关文献复习。

结果

4例APL继发t-MN患者均为女性，中位年龄42（40~53）岁，3例接受了以维甲酸（ATRA）+亚砷酸（ATO）为基础联合蒽环/蒽醌类药物±阿糖胞苷的前期诱导缓解及巩固治疗方案，1例采用了ATRA联合蒽环/蒽醌类药物±阿糖胞苷的治疗方案，均没有使用烷化剂。在APL获得完全缓解（CR）后40~43个月出现t-MN，其中治疗相关性骨髓增生异常综合征（t-MDS）1例，治疗相关性急性髓系白血病（t-AML）3例，出现t-MN时PML-RARα融合基因均为阴性。3例t-AML患者接受了2~4个疗程再诱导治疗，其中有1例t-AML患者在获得CR后行异基因造血干细胞移植（allo-HSCT），1例t-MDS患者接受了去甲基化治疗。中位随访54.5（48~62）个月，2例t-AML患者死亡，出现t-MN后中位生存期为12（5~18）个月。1989至2018年文献共报道63例APL继发t-MN病例，与本次报道的4例汇总分析，67例患者中男27例，女40例；中位年龄为52.5（15~76）岁；中位潜伏期39（12~168）个月，确诊t-MN后中位生存时间为10（1~39）个月。

结论

APL继发t-MN较为少见，目前缺乏有效的防治措施，预后不佳，在随访过程中（尤其是获得CR后39个月左右）若出现病情变化，应警惕t-MN的发生，对此类患者应尽快明确疾病的变化，给予合理的治疗。

[Endemic situation of schistosomiasis in People's Republic of China from 2010 to 2017]

OBJECTIVE

To understand the epidemic trend of schistosomiasis in China from 2010 to 2017 so as to provide the scientific evidence for schistosomiasis elimination.

METHODS

The information of schistosomiasis control nationwide from 2010 to 2017 was collected, including the endemic of population, status of livestock control, and Oncomelania hupensis snail control. Microsoft Excel was applied for datum management and analysis.

RESULTS

From 2010 to 2017, the epidemic of schistosomiasis in China dropped significantly. The decreasing amplitude of estimated number of patients nationwide was 88.46%. Seventy-one acute schistosomiasis patients were reported and 12.68% (9/71) of them were imported. The decreasing rate of cultivated cattle was 50.09%, and the accumulative number of schistosome-infected cattle was 17 239, and the average positive rate of stool examinations decreased from 1.04% to 0.000 22%. The area with snails nationwide was 373 596.18 to 363 068.95 hm², and the new detected area with snails was 46.71 to 1 346.73 hm². The area with schistosome-infected snails was 171.68 hm² in 2012 and it was 9.25 hm² in 2013. In 72 key monitoring points of 7 endemic provinces, there were 17 schistosome positive points of water body in 2010 and 6 points in 2016. There were some high risk-factors related to schistosomiasis transmission including schisto-some-infected cattle, dogs, and field rats, and the field stools, and the pasture in the area with snails in schistosomiasis monitoring points.

CONCLUSIONS

The endemic status of schistosomiasis in China has dropped significantly, and the transmission level is very low. However, the infectious source and risk factors in the endemic environments have not be eliminated. Therefore, the infectious source control, health education, snail control, and transmission monitoring should be strengthened, so as to promote the progress of schistosomiasis elimination.

[Research advances in the mammalian target of rapamycin signaling pathway and its inhibitors in treatment of hepatocellular carcinoma]

Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase in the downstream of the phosphatidylinositol 3-kinases (PI3K) family. This kinase plays an important role in the development and progression of hepatocellular carcinoma (HCC). Preclinical data demonstrate that 40%-50% of HCC patients have dysregulated expression of the effectors of the mTOR signaling pathway, and the activation of the mTOR pathway is associated with poorly differentiated tumors, early tumor recurrence, and poor survival/prognosis. This article reviews the research advances in the potential role of the mTOR signaling pathway and its inhibitors in the treatment of HCC.

[Retinal image quality in northern rural Chinese adult population]

Objective: To assess the retinal image quality of the normal northern rural Chinese adult population. Methods: A normal population-based, cross-sectional study. From Oct, 2012 to Jan 2013, a clustered, random sampling procedure was used to select normal population who visual acuity≤ 0(LogMAR) and 30-69 years old from 2 villages. All eligible subjects were invited to undergo a comprehensive eye examination, and the retinal image quality related index were examined with pupil 4 mm using objective optical quality analysis systemⅡ(OQAS Ⅱ, Visiometrics, Spain), including MTFcutoff, VA20, VA9, PSF50, PSF10, OSI, SR. And describe the retinal image quality of different age group, including 30-39y, 40-49y, 50-59y, 60-69y. Results: Among 1 108 participants (61.9%) that completed examinations in our center, 681 participants (1 362 eyes) were recruited. There were 146, 586, 440 and 190 eyes in each group. The spherical equivalent refraction of each group was (-0.35±0.84), (-0.19±0.50), (-0.03±0.54) and (0.20±0.71) D. The best corrected vision acuity of each group was -0.02±0.04, -0.01±0.03, -0.01±0.02 and -0.00±0.01. The MTFcutoff of each group was (37.06±9.31), (36.69±8.93), (36.52±9.05) and (32.61±10.08) c/deg. Retinal imaging parameters were significantly different(MTFcutoff: MD=4.45, SR:MD=0.03, PSF50: MD=-0.45, PSF10: MD=-2.87, VA20:MD=0.13, A9:MD=0.09, OSI:MD=-0.41, P<0.001)between aged 30-39 group and aged 60-69 group. Objective scattering index (OSI) were significantly different(MD=-0.13, P=0.004)between aged 30-39 group and aged 50-59 group. Retinal imaging parameters were significantly different(MTFcutoff:MD=4.45, SR:MD=0.03, PSF50:MD=-0.45, PSF10:MD=-2.87, VA20:MD=0.13, VA9: MD=0.09, OSI: MD=-0.41, P<0.001)between aged 40-49 group and aged 60-69 group. Retinal imageing parameters were significantly different(MTFcutoff: MD=4.45, SR: MD=0.03, PSF50: MD=-0.45, PSF10: MD=-2.87, VA20:MD=0.13, VA9:MD=0.09, OSI:MD=-0.41,P<0.001)between aged 50-59 group and aged 60-69 group. Conclusion: Retinal image quality was gradually worse over time in the northern rural Chinese adult population. (Chin J Ophthalmol, 2018, 54:593-598).

[Clinical effect of compound internal fixations in treating extreme distal radial fractures]

Objective: To investigate the clinical character and treating strategy of extreme distal radial fractures. Methods: From June 2012 to May 2014, 12 patients who suffered from extreme distal radial fractures were treated in Department of Orthopedics, Tongji Hospital, Tongji University. According to AO/OTA classification, there were 4 cases of type 23B1, 3 cases of 23B2, 3 cases of 23C1 and 2 cases of 23C3.When classified by morphological features, there were 4 of simple styloid process fracture, 3 of simple extreme distal radial fracture without articular surface involved, 3 of styloid process fracture combined with distal radial articular fracture, and 2 of articular surface splintered or collapse fracture. According to the fracture features that radiographic exams showed, different surgical paths and fixation methods were chosen in order to protect soft tissues to the best advantage. To those patients with simple styloid process fracture, screw alone, Kirschner-wire or styloid plate were used for fixation. To the other types of fracture, open reduction and compound internal fixation with low-notch volar plate, dorsal or volar mini-plate, screw or Kirschner-wire was applied to ensure the stability of fixation, and maximally protect soft tissues like tendons, ligaments and neurovascular bundles, counting on the "stuffing-squeezing" effects after reduction or reconstruction of the articular surface. Situation of the wound and soft tissue were mainly checked in the first 2 weeks, and in the 3rd month post-operatively, fracture reduction and internal fixation were evaluated by radiographic methods like X-ray and CT scan. When 12 months post-operatively, not only radiographic follow-up such as fracture reduction, internal fixation and osteoarthritis were taken, but also some other evaluation, such as pain of wrist, rotation range of forearm, grip strength, and function of wrist according to DASH scores. Results: All of the 12 cases were followed up for at least 1 year. The wound healed well in all cases 2 weeks post-operatively, and no soft tissue infections, necrosis or neurovascular complications occurred. All fractures healed and no loss of reduction occurred 3 months post-operatively. Internal fixations were at good condition except in 2 cases, whose Kirschner-wire had been removed 2.5 and 2.8 months after the operation due to loosening and partly backing out on dorsal side. When followed up at 12 months post-operatively, one from these 2 patients suffered from a mild pain of wrist, and grip strength together with the function of the affected wrist dramatic declined when compared to the unaffected side. With the help of radiograph, local collapse on the articular surface was found, which meant to be traumatic arthritis. There were no pain in the rest 11 cases, and flexion-extension range of the wrist, rotation range of forearm and grip strength of the affected side recovered to over 80% of the unaffected side, with a DASH score was from 7 to 15 points(average 11.9 points)below 15 points. Conclusions: Traditional volar plates can not be used for extreme distal radial fractures. It may be an effective way to treat extreme distal radial fractures with compound internal fixation on the basis of morphological feature of fractures and the situation of soft tissue because of vivid of the fixation, reducing damage of soft tissue and early functional training.

Policy Support and Resources Mobilization for the National Schistosomiasis Control Programme in The People's Republic of China

Schistosomiasis remains a public health problem in many developing countries around the world. After the founding of The People's Republic of China, from 1949 till date, all levels of government, from central to local, have been attaching great importance to schistosomiasis control in The People's Republic of China. With considerable policy support and resources mobilization, the national schistosomiasis control programmes have been implemented during the past 65years. Here, we summarize the successful experience of schistosomiasis control during the process. Recommendations for the future management of the Chinese national schistosomiasis elimination programme are put forward after considering the remaining challenges, shortcomings and lessons learnt from 65years of schistosomiasis control drives in The People's Republic of China. They will help to sustain past achievements, foster the attainment of the ultimate goal of schistosomiasis elimination for the country and provide reference for schistosomiasis control programme in other countries.

The Establishment and Function of Schistosomiasis Surveillance System Towards Elimination in The People's Republic of China

Schistosoma japonicum is the main schistosome species in The People's Republic of China, causing intestinal schistosomiasis, a debilitating disease of public health importance. The People's Republic of China used to be heavily endemic with schistosomiasis, but great progress has been made through the vigorous efforts of the national control programmes in the last six decades. Presently, efforts are geared towards eliminating schistosomiasis from The People's Republic of China by the end of 2025 through effective schistosomiasis surveillance, an important component in the drive towards schistosomiasis elimination. Therefore, this article explicitly outlines the development and progress made in schistosomiasis surveillance since 1990 with a special focus on the new surveillance system in use. Although the surveillance system has steadily improved over the years, it is faced with many challenges. Hence, more efforts are needed to establish an effective and sensitive evaluation system for the national schistosomiasis elimination programme in The People's Republic of China.

Ferroelectricity and ferromagnetism of La(0.5)Lu(0.5)Ni(0.5)Mn(0.5)O(3) thin films on Nb:SrTiO(3) substrates

Epitaxial orthorhombic La(0.5)Lu(0.5)Ni(0.5)Mn(0.5)O(3) (LLNMO) thin films deposited on Nb:SrTiO(3) (NSTO) substrates are prepared by pulsed laser deposition and their ferroelectricity and magnetism are investigated using various techniques. It is revealed that the as-prepared thin films are ferromagnetic (FM) insulators. The FM transition occurring at ∼ 125 K is evidenced by the well defined hysteresis at low temperature, with a saturated magnetic moment as high as 1.8 µ(B)/f.u. at ∼ 5 K. A reversible ferroelectric polarization of ∼ 0.2 µC cm(-2) below ∼ 140 K is also observed. The magnetism can be understood by the FM ordering associated with a partially ordered major Ni(2 +)-Mn(4 +) plus minor Mn(3+)-Ni(3+) configuration, while the ferroelectricity is argued to originate from the A-site disordering of La(3+) and Lu(3+).

A Simple Method to Synthesize Cadmium Hydroxide Nanobelts

Cd(OH)₂nanobelts have been synthesized in high yield by a convenient polyol method for the first time. XRD, XPS, FESEM, and TEM were used to characterize the product, which revealed that the product consisted of belt-like crystals about 40 nm in thickness and length up to several hundreds of micrometers. Studies found that the viscosity of the solvent has important influence on the morphology of the final products. The optical absorption spectrum indicates that the Cd(OH)₂nanobelts have a direct band gap of 4.45 eV.