Table of Content

30 October 2019, Volume 37 Issue 5

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INVITED REPORTS

From control to elimination: the historical retrospect of malaria control and prevention in China

Jun FENG, Shui-sen ZHOU

2019, 37(5):  505-513.  doi:10.12140/j.issn.1000-7423.2019.05.001

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Malaria used to be a severe parasitic disease that seriously harmed and endangered the health and safety of people and thwarted social and economic development in China. After performing comprehensive control and prevention measures for nearly 70 years since the founding of new China, China’s malaria prevention work has achieved remarkable results, effectively controlling the malaria epidemic, ensuring people’s health and promoting social and economic development. In 2017, no indigenous malaria case was reported nationwide for the first time. The zero indigenous case remained in 2018. This review gives a historical retrospect of the epidemic characteristics of malaria, the achievement, the lesson learned, the challenges and prospects for malaria control and elimination in China.

China fighting against schistosomiasis for 70 years: progress and experience

Shan LV, Jing XU, Chun-li CAO, Li-juan ZHANG, Shi-zhu LI, Xiao-nong ZHOU

2019, 37(5):  514-519.  doi:10.12140/j.issn.1000-7423.2019.05.002

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It has been 70 years to implement schistosomiasis control in China, which can be divided into five stages including the initiating preparedness, mass-based campaign, achievement consolidation, mass drug administration, control of infection source. A striking success in schistosomiasis control was achieved in China in the past decades with infected people declined from 9.49 million in 1957 to 30 000 in 2018. The great achievement is attributed to the central role of the Communist Party and the Government, integrated control, scientific strategies, and professional staff. The reduction and control of schistosomiasis could not come to truth without the leadership of endeavor of Communist Party and Government. In the march toward elimination the following measures are recommended, 1) improving the mechanism of schistosomiasis control and strengthening the leadership of governmental, 2) abiding by the law of disease control and making appropriate planning, 3) establishing the sensitive and effective surveillance system and focusing on the prevention, 4) promoting scientific management and implementing precision control.

ORIGINAL ARTICLES

Truncated Plasmodium berghei putative secreted ookinete protein 7 induces transmission-blocking immunity

Wen-qi ZHENG, Jun-rui WANG, Hua WANG, Fei LIU, En-jie LUO, Ya-ming CAO, Yan-qiu HAN

2019, 37(5):  520-525.  doi:10.12140/j.issn.1000-7423.2019.05.003

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Objective To investigate the truncated Plasmodium berghei putative secreted ookinete protein 7 (PbPSOP7) induces transmission-blocking immunity determined by in vitro antibody blocking and mosquito feeding assays. Methods Recombinant PbPSOP7 protein (rPbPSOP7) was expressed in E. coli and the anti-rPbPSOP7 sera were obtained by immunizing BALB/c mice for three times with rPbPSOP7 formulated with Freund’s adjuvant. For in vitro test, P. berghei-infected mouse blood was obtained from a mouse infected with 5 × 10⁶ P. berghei for three days, then co-incubated with mouse anti-rPbPSOP7 sera at 1 : 5, 1 : 10 and 1 : 50 dilutions. Mouse anti- a non-relevant His-tag protein serum at the same dilutions was used as control. The inhibition on the exflagellation of Plasmodium gametocytes was observed 15 min after the culture and the inhibition on the ookinete development was observed 24 hours after incubation. For mosquito feeding experiment, 5 mice were each immunized with 50 μg of rPbPSOP7 formulated with Freund’s adjuvant for three times, then infected with 5 × 10⁶ P. berghei by intraperitoneal injection 10 days after the last immunization. Three days post-infection, the mice were fed by at least 50 female anopheles mosquitoes. The mosquitoes were dissected 10 days after the blood feeding, the infection rate and the reduced number of oocysts in each infected mosquito were calculated compared with mosquitoes fed with mice immunized with His-tag control protein. The feeding experiment was repeated three times. Results When incubated with mouse anti-rPbPSOP7 sera at the 1 : 5, 1 : 10 or 1 : 50 dilutions for 15 min, the exflagellation of gametocytes was decreased by 22.0%, 8.0% and 2.0% compared to Plasmodium incubated with sera from mice immunized with His-tag protein(P > 0.05). After incubated with mouse anti-rPbPSOP7 sera for 24 hours, the significant inhibition of ookinete development was observed in the culture with different dilutions of the antisera. The development of ookinete was reduced by 69.2%, 56.4% and 48.6% when incubated with anti-rPbPSOP7 sera at 1 : 5, 1 : 10 and 1 : 50 dilutions, respectively, compared with control sera group (P < 0.01). Three independent mosquito feeding experiments showed that, compared with the control group, the development of oocysts in the midgut of mosquitoes in immunized group was significantly decreased from 87.1 ± 69.3, 96.4 ± 82.9 and 85.3 ± 69.1 to 31.1 ± 34.9, 30.2 ± 32.3 and 29.1 ± 35.1, respectively. Anti-rPbPSOP7 sera reduced the development of oocyst by 64.2%, 68.6% and 65.8% in three independent feeding experiments (P < 0.01). The infection rates of P. berghei in mosquitoes decreased from 96.4% (27/28), 89.3% (25/28) and 89.3% (25/28) to 78.6% (22/28), 78.6% (22/28) and 75.0% (21/28) in three experiments, with 17.8%, 10.7% and 14.3% reduction (P > 0.05). Conclusion Immunization of rPbPSOP7 induced transmission-blocking immunity characterized by reduced development of P. berghei ookinate and oocyst in mosquitoes, indicating that PbPSOP7 is a potential malaria transmission-blocking vaccine candidate.

Effect of artesunate combined with erythropoietin on the expression of cerebral malaria-associated factors in mice

Yun-ting DU, Wei ZHAO, Lan XU, Xue-xing ZHANG

2019, 37(5):  525-531.  doi:10.12140/j.issn.1000-7423.2019.05.004

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Objective To understand the effects of artesunate (ART) combined with recombinant human erythropoietin (rhEPO) on the expression of cerebral malaria-associated factors in the brain of Plasmodium berghei-infected mice and the underlying mechanism. Methods Forty female C57BL/6 mice were divided into 5 groups (n = 8 in each group). Four groups of mice were infected with P. berghei ANKA strain by intraperitoneal injection of 1 × 10⁶ P. berghei-infected mouse erythrocytes. Two to four days post infection, mice in infection control group were not treated; Mice in ART group were each treated orally with 40 mg/(kg·d)of ART in a total volume of 200 μl by garvage; Mice in rhEPO group were each treated with 50 U rhEPO by intravenous injection; Mice in ART+rhEPO group were each treated with both ART and rhEPO at above mentioned dosage and route. The last group of mice was given with PBS only as normal control. The treatment was performed for consecutive 3 days. The parasitemia in blood of each mouse was observed by Giemsa-stained thin blood smears and the mortality was monitored 4 days post infection. The sera were collected from eyeball blood 5 days post infection. The levels of IFN-γ, TNF-α and IL-10 in the serum of each mouse were measured by ELISA. Four mice in each group were sacrificed by cervical dislocation 5 days post infection and the brain samples were collected. The relative expression levels of NF-κB, granzyme B, IFN-γ, VCAM-1 and ICAM mRNA in the brains were detected by quantitative real-time PCR (qRT-PCR). The percentage and absolute numbers of CD4⁺ and CD8⁺ T cells in brain were counted by flow cytometry. Results In infection control group, mice exhibited neurological symptoms and began to die around 6 days post infection and all mice died 12 days post infection, while mice in ART group and rhEPO group began to die 8 and 10 days post infection, respectively, and all mice died 26 days post infection. However, the significant improvement of mortality in combination group of ART+rhEPO was observed with prolonged occurrence of death (12 day post infection) and survival rate of 50% at 26 days post infection. The blood smear results showed that the ART+rhEPO group had significantly lower parasitemia(3.14% on day 6 to 7.10% on day 12) than group treated with rhEPO alone (4.96%-15.50%) or group without treatment (4.98%-19.90%) during day 7 to 12 post-infection. ELISA results showed that the levels of pro-inflammatory cytokines IFN-γ and TNF-α in the sera of ART+rhEPO treated mice were (378.94 ± 145.18) pg/ml and (109.89 ± 27.05) pg/ml, respectively, which were significant lower than that in infection control group [(726.09 ± 35.40) pg/ml and (345.97 ± 42.70) pg/ml, P < 0.05 or P < 0.01, respectively]. The level of IFN-γ in the ART+rhEPO group was also significantly lower than that in ART group [(795.46 ± 64.48) pg/ml, P < 0.01]. Meanwhile, the anti-inflammatory cytokine IL-10 in ART+rhEPO group [(224.18 ± 22.93) pg/ml] was significantly higher than that in infection control group [(90.72 ± 6.30) pg/ml] and in ART group [(103.99 ± 18.04) pg/ml] (P < 0.01). The relative mRNA expression levels of NF-κB, granzyme B, VCAM-1, ICAM-1 and IFN-γ in the brains of ART+rhEPO group (0.89 ± 0.59, 17.23 ± 4.39, 1.63 ± 0.21, 1.48 ± 0.16, and 11.68 ± 2.63, respectively) were significantly lower than that in the mice of infection control group (3.62 ± 0.36, 88.54 ± 21.13, 2.65 ± 0.50, 3.13 ± 0.62, and 60.56 ± 4.19, respectively) (P < 0.05 or P < 0.01). The relative mRNA expression levels of NF-κB, granzyme B, ICAM-1 and IFN-γ were significantly lower than that in rhEPO group (2.00 ± 0.59, 58.55 ± 1.11, 2.68 ± 0.29, and 44.69 ± 1.17, respectively) (P < 0.05 or P < 0.01). At the same time, the percentage of CD4⁺ T and CD8⁺ T cells in the brains of ART+rhEPO group [(1.29 ± 0.06)% and(1.68 ± 0.28)%] was significantly lower than that in the mice of infection control group [(2.77 ± 0.26)%, and (5.30 ± 0.35)%, P < 0.01, respectively] and ART group [(2.04 ± 0.66)% and (3.65 ± 0.14)%, P < 0.01, respectively]. Conclusion Combined treatment of ART with rhEPO significantly inhibit the infection level of P. beighei and reduce the expression of cerebral malaria associated factors in mice. The mechanism underlying the inhibition is possibly related to the down-regulation of pro-inflammatory cytokines/chemokines and reduced filtration of CD4⁺/CD8⁺ T cells in the brain, and up-regulation of anti-inflammatory cytokine IL-10.

Challenges in malaria elimination: the epidemiological characteristics of Plasmodium vivax in China from 2011 to 2018

Li ZHANG, Jun FENG, Hong TU, Zhi-gui XIA, Shui-sen ZHOU

2019, 37(5):  532-538.  doi:10.12140/j.issn.1000-7423.2019.05.005

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Objective To analyze the epidemiological characteristics of Plasmodium vivax in China from 2011 to 2018 so as to provide the evidence-based technical and theoretical support for the elimination of malaria in China. Methods The epidemiological data of P. vivax infection was collected from 31 provinces (municipalities, autonomous regions excluding Hong Kong, Macau and Taiwan) from 2011 to 2018. The data of epidemic situation, regional distribution, infection source were analyzed. Results A total of 7 768 P. vivax infected cases were reported in 30 provinces (municipalities and autonomous regions) except for Qinghai from 2011 to 2018, accounting for 30.0% of the total reported malaria cases (7 768/25 874). The reported of P. vivax cases have declined from 2 634 cases (accounting for 58.6% of the total malaria cases) in 2011 to 352 cases (accounting for 14.0% of the total malaria cases) in 2018. The reported P. vivax cases were mainly distributed in Yunnan (48.6%, 3 772/7 768), Anhui (7.9%, 612/7 768), Sichuan (7.8%, 604/7 768), Hunan (4.6%, 354/7 768), and Henan (3.9%, 303/7 768). Only 3 local vivax malaria cases were reported in 2016. There was no local P. vivax case reported in 2017 and 2018. The imported 6 227 P. vivax cases were reported in 30 provinces during 2011-2018, mainly in Yunnan (50.7%, 3 160/6 227), Sichuan (9.4%, 585/6 227), Hunan (5.6%, 349/6 227), Henan (4.8%, 297/6 227) and Guangxi (4.4%, 271/6 227). Totally 65 countries in 4 continents were recorded as the sources of P. vivax infection for the imported cases. 4 232 P. vivax cases (68.0%, 4 232/6 227) were imported from 16 countries in Asia including Myanmar (54.9%, 3 419/6 227), Indonesia (4.2%, 264/6 227), and Pakistan (2.9%, 182/6 227). A total of 1 556 cases (25.0%, 1 556/6 227) were imported from 44 countries in Africa including Ethiopia (9.3%, 580/6 227), Ghana (2.5%, 155/6 227) and Equatorial Guinea (1.5%, 96/6 227). Besides, 17 P. vivax cases were imported from 4 countries in South America (0.3%, 17/6 227), and 60 cases imported from 2 countries in Oceania (1.0%, 60/6 227). Conclusion P. vivax cases were reported decreasingly from 2011 to 2018. No local P. vivax cases occurred in China in 2017 and 2018. However, the imported P. vivax infection source has been identified in 65 countries from Africa, Asia, South America and Oceania. Therefore, the measures in elimination and post-elimination should continue to be strengthened to prevent re-establishment of the imported vivax malaria.

Risk factors of malaria infection in people returned from a travel to Africa in Shanglin, Guangxi

Kang-ming LIN, Duo-quan WANG, Shi-zhu LI, Ying-jun QIAN, Jun-yun WANG, Jun-hu CHEN, Bin XU, Jian TAN, Jian-feng CHEN, An-xiang MA, Fei LUO, Wei-dong LI, Tao ZHANG, Jun LI, Yi-chao YANG, Xiao-nong ZHOU

2019, 37(5):  539-544.  doi:10.12140/j.issn.1000-7423.2019.05.006

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Objective To identify the risk factors related to malaria infection in those who traveled to Africa and returned to Shanglin County of Guangxi. Methods An epidemiological investigation and Plasmodium detection were done using a case-control study method in 2018. The cases with Plasmodium positive examined by microscopy or PCR test were grouped as case group, while those with negative results were grouped as a control group. The malaria infection risk factors were investigated by a questionnaire answered by those returned from a travel to Africa, with and without malaria infection. The questionnaire included general information, past medical history and anti-malaria treatment, working and living conditions when abroad, knowledge of malaria prevention and control and behavioral awareness related to malaria infection and so on. The collected information was analyzed to compare the difference of each factor between the case group and the control group. The potential risk factors related to malaria infection were analyzed using an unconditional multivariate logistic regression analysis method by setting the case group as the result variable and other factors as the explanation variable. Results Total 465 people returned from a travel to Africa were enrolled in the investigation related to the malaria infection in Africa, among them 149 were identified as Plasmodium infection positive and 316 as negative. Univariate analysis showed that there were significant differences for the five variables between the case group and the control group (P ≤ 0.05), including age (< 30: 17.5% and 7.6%, 30-39: 40.3% and 40.8%, 40-39: 24.2% and 32.6%, ≥ 50: 18.1% and 19.0%）, living ecological environment (forest: 41.6% and 43.4%, jungle: 41.6% and 26.3%, meadow: 5.4% and 3.5%, uncultivated: 10.7% and 22.8%, mixed: 0.7% and 4.1%), the cultivated crop type (rice: 95.3% and 89.9%, other: 4.7% and 10.1%), outdoor activities in the evening (yes: 56.4% and 62.0%, no: 43.6% and 38.0%), and outdoor activity spent time (no: 43.6% and 38.0%, 1-30 min: 8.1% and 17.4%, 31 min-1 h: 1.3% and 2.9%, 1-2 h: 0.7% and 1.6%, ≥ 2 h: 46.3% and 40.8%), respectively. Multivariate logistic regression analysis showed that the living environment in Africa for case group and control group was in city： 4.0%, 2.2%; in countryside: 7.4%, 3.5%; in the wild: 87.3%, 91.8%; and mixed： 1.3%, 2.5%, respectively, with OR = 1.8(1.0-2.8). The living house for case group contained less percentage of window and door screen (7.4%) than control group (12.0%) with OR = 0.2 (0.1-0.8). Conclusion The results conclude that people who lived in houses without door and window screens, went outdoors in the evening, and spent longer time outdoors had higher chance to get malaria and these activities are the important risk factors for malaria infection in Africa. Interestingly, people living in the city or integrated areas had the higher risk to get infected than those living in the field.

Analysis of epidemic situation of the imported malaria and the control strategies in Lianyungang City from 2005 to 2018

WANG Jin-ling, WU Zhou-wei, ZHAO Si-qi, ZHAO Zhong-shun, MAO Yan-min

2019, 37(5):  545-551.  doi:10.12140/j.issn.1000-7423.2019.05.007

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Objective To analyze the epidemic situation of imported malaria in Lianyungang, Jiangsu from 2005 to 2018, so as to formulate a better prevention and control strategy of malaria suitable for the area.Methods Information of malaria cases identified in Lianyungang from 2005 to 2018 were collected from Infectious Diseaes Report System of Disease Control and Prevention, Malaria Epidemic, Case Investigation Data, Public Helth Intervention and other related information. The malaria database was established using Epidata 3.0 and analyzed using SPSS17.0 software.Results Total 324 cases of imported malaria were reported from 2005 to 2018 in Lianyungang region with two peaks happened in 2008 (30 cases) and 2013-2015 (54, 42 and 59 cases, respectively). The incidence of imported malaria decreased since 2016 with 36 cases in 2016, 22 cases in 2017 and 20 cases in 2018. Almost all the cases (99.1%, 321/324) were imported from abroad, with only 3 cases (0.9%) were domestically imported from other provinces in China. For those imported cases, 96.9% of them were imported from Africa, of which 39.2% from Equatorial Guinea (123 cases) and 17.2% from Angola (54 cases). All cases were male, 45.1% of them were within the age of 40-49 years old (146 cases). Most of them (91.0%, 295/324) were the migrant workers returned from abroad. There was no seasonal difference of imported malaria cases. Total 75.6% (245/324) of them were infected with Plasmodium falciparum, 4.3% (14 cases) with P. vivax, 14.5% (47 cases) with P. oval, 4.6% with P.malariae (15 cases) and 0.9% (3 cases) were the mixed-infection. Donghai county contained the most cases (46.9%, 152/324), followed by Ganyu District (33.0%, 107/324). Half of the malaria cases seeked for the first medication at local CDC (156 cases) and half at the local medical institutions (156 cases), but most of the malaria cases received confirmed diagnosis at local CDC (62.0%, 201/324). Out of all imported cases, 12 were severe malaria with 2 cases died. A KAP survey (knowledge, attitudes and practices) on malaria was performed among the people who worked abroad at the high-risk malaria areas and their families members in Donghai County, Ganyu District and other places. After education and health intervention, the knowledge awareness rate for malaria prevention, the correct attitude rate and the good practice rate increased from 19.7%, 36.9% and 76.6% to 84.4%, 88.0%, and 95.8%, respectively.Conclusion The epidemic situation of imported malaria was declined in recent years in Lianyungang City. It is important to enhance the management of the infectious sources, improve the malaria diagnosis and treatment, and strengthen the health education of migrant workers and their families in order to achieve better prevention and control of imported malaria in the area.

Comparative expression of HSP90α and KPNA2 genes in different tissues of Microtus fortis and their effects on the resistance against Schistosoma japonicum infection in recipient mice

Gang CHENG, Qian-bo WANG, qiang GONG, De-hui XIONG

2019, 37(5):  552-556.  doi:10.12140/j.issn.1000-7423.2019.05.008

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Objective To determine the expression levels of Schistosoma-resistant genes HSP90α (heat shock protein-90α) and KPNA2 (Karyopherin α2) in different tissues of rodent Microtus fortis and their effects on the resistance against S. japonicum infection in recipient mice. Methods RT-PCR was used to determine the levels of mRNA expression of HSP90α and KPNA2 in different tissues (heart, liver, spleen, lung, kidney, brain, muscle, skin and bone marrow) of normal M. fortis. To determine the effect of HSP90α and KPNA2 on their resistance against S. japonicum infection, the recombinant retroviral vectors containing target genes, pLXSN-HSP90α and pLXSN-KPNA2, were used to make recombinant viruses. The viruses containing the target HSP90α and KPNA2 were used to transfect naive Kunming mice on day 1, 3, 7 by tail vein injection of 4×10⁵ cfu viruses to make them expressed in the recipient mice. The mice were then infected with (30 ± 2) cercaria of S. japonicum 2 days after the final injection of viruses. The mice received empty vector or PBS were used as negative controls. All mice were euthanized 42 days after cercaria challenge and adult worms were collected by portal vein drainage and livers collected to measure the egg count and the egg granuloma by HE staining. The HSP90α and KPNA2-induced resistance against S. japonicum infection was measured by the adult worm reduction, egg count reduction and the reduced liver egg-granuloma compared to mice received empty vector or PBS only. Results RT-PCR results showed that HSP90α gene was highly expressed in the brain and bone marrow of M. fortis, while KPNA2 gene highly expressed in heart, kidney and muscle. The cercaria challenge study showed that mice transfected with pLXSN-HSP90α and pLXSN-KPNA2 viruses produced 40.80% and 39.42% adult worm reduction, and 57.90% and 76.50% egg reduction, respectively, with statistical significance compared with mice received pLXSN vector only (P < 0.01). However, there was no significant difference in adult worm reduction between mice received pLXSN-HSP90α and pLXSN-KPNA2, but with significant difference for egg count reduction (57.9% for pLXSN-HSP90α group and 76.5% for pLXSN-KPNA2 group, P < 0.05). The liver sections showed that mice received pLXSN-HSP90α and pLXSN-KPNA2 had significantly less number of eggs and egg granuloma compared to mice received empty vector only. Conclusion HSP90α and KPNA2 genes are expressed differently in brain, bone marrow, heart, kidney and muscle tissues of M. fortis. Mice received viruses containing M. fortis HSP90α and KPNA2 genes acquired significant resistance against S. japonicum infection characterized by the reduced adult worms and reduced egg count and granuloma in livers of infected mice.

Spatial autocorrelation analysis of current schistosomiasis case distribution in Anhui Province

Feng-hua GAO, Jia-chang HE, Shi-qing ZHANG, Tian-ping WANG, Ting-ting LI, Jing-bo XUE, Shi-zhu LI

2019, 37(5):  556-562.  doi:10.12140/j.issn.1000-7423.2019.05.009

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Objective To analyze the spatial distribution of current schistosomiaisis cases in Anhui Province as reference for facilitating the control of the disease. Methods The epidemiological data of current schistosomiasis cases in Anhui from January 2017 to October 2018, including age, gender, occupation, education, current address, disease stage, economic status, health insurance and treatment, were collected from Epidemiological Dynamics Data Collection Platform (EDDC). A database of Anhui schistosomiasis cases was established using Microsoft Excel 2010. SPSS18.0 was used to analyze the statistical significance of epidemiological characteristics of schistosomiasis cases in Anhui. ArcGIS 10.2 clustering module was used to analyze the spatial autocorrelation of chronic and advanced schistosomiasis cases identified at township level, among them the global spatial autocorrelation analysis was performed using global Moran’s I index and the local spatial autocorrelation analysis using local Getis-Ord G coefficient. Results A total of 20 345 schistosomiasis cases were reported in the province during January 2017-October 2018, including 15 080 chronic clinic cases and 5 265 advanced cases. There was no acute case reported during the period. More male cases (11 319) than female cases (9 026) were reported with male and female ratio of 1.25 : 1. Average age of all cases was 57.8 ± 12.2. Among all chronic cases, the average age was 54.8 ± 11.2 years old. Most of the cases were farmers (96.4%, 14 540/15 080) with low education (primary school/51.9%, middle school/23.0% and illiterate/21.8%). Total 4.9% (736/15 080) of the chronic cases came from families with low income. Among all advanced cases, the average age was 66.4 ± 10.7 years old. The main occupation was farmers (93.8%, 4 936/5 265) with low education level (illiterate/43.6%, primary school/38.1% and middle school/15.2%). More than 10% of the cases (528/5 265) came from the poor families with low income. Chronic cases were distributed in 249 townships within 42 counties (cities or districts) along Yangtze River Basin. There were 38 townships with prevalence of chronic cases higher than 0.5%. The advanced cases were mainly distributed in 340 townships within 45 countries (cities or districts) along Yangtze River Basin and Xin’an River Basin. There were 3 counties with prevalence of advanced schistosomiasis cases higher than 0.5%. The global autocorrelation analysis at the township level showed that both prevalence of chronic schistosomiasis (Moran’s I = 0.202 5, P < 0.01) and the advanced schistosomiasis (Moran’s I = 0.183 4, P < 0.01) possesed spatial autocorrelation in Anhui Province. Analysis of local autocorrelation showed that highly concentrated areas of chronic schistosomiasis were mostly distributed in the townships along the upper and middle reaches of the Yangtze River in Anhui, and highly concentrated areas of advanced schistosomiasis were mainly distributed along the upper and middle reaches of the Yangtze River and the Xin’an River Basin. Conclusion There is spatial accumulation of schistosomiasis case in Anhui Province. The upper and middle reaches of the Yangtze River remain the key areas for schistosomiasis prevention and control in Anhui Province.

Cloning, expression and immunoreactivity of Toxoplasma gondii gliding-associated protein 45

Run-hua LI, Li GUAN, Guo-rong YIN

2019, 37(5):  563-567.  doi:10.12140/j.issn.1000-7423.2019.05.010

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Objective To clone and express Toxoplasma gondii gliding-associated protein 45 (TgGAP45) as recombinant protein and analyze its immunoreactivity by T. gondii infected human serum for its potential as an immunodiagnostic antigen. Methods Total RNA was extracted from tachyzoites of T. gondii RH strain and reversely transcribed into cDNA (RT-PCR). The DNA encoding for the open reading frame of TgGAP45 was amplified with gene-specific primers based on TgGAP45 sequence(GenBank accession No. AF453384.1). The PCR products were cloned into bacterial expression vector pET-30a(+) using EcoRⅠ and XhoⅠ sites. The correct recombinant plasmid pET-30a(+)-TgGAP45 was identified by PCR with gene-specific primers, double restriction enzyme digestion and DNA sequencing. The pET-30a(+)-TgGAP45 plasmid DNA was transformed into E. coli Rosetta (DE3) and the recombinant TgGAP45 protein (rTgGAP45) was expressed under induction of IPTG. The rTgGAP45 was purified with Ni-NTA column and analyzed by SDS-PAGE for its purity and Western blotting for its immune-recognition by T. gondii infected human serum and mouse anti-T. gondii soluble tachyzoites antigen (STAg) serum. Results DNA coding for TgGAP45 was successfully amplified from T. gondii tachyzoites total RNA by RT-PCR as 750 bp in length, then cloned into bacterial expression vector pET-30a(+). The correct recombinant plasmid pET-30a(+)-TgGAP45 was identified by gene-specific PCR, double restrict enzyme digestion and DNA sequencing. The TgGAP45 was successfully expressed as soluble recombinant protein in E. coli BL21 (DE3) under induction of IPTG with a rough molecular weight of 35 000, and purified with Ni-NTA. The His-tagged rTgGAP45 was strongly recognized not only by the anti-His antibody, but also by T. gondii-infected human serum and mouse anti-T. gondii STAg serum by Western blotting. Conclusion DNA encoding for TgGAP45 was successfully cloned from T. gondii tachyzoites and rTgGAP45 was efficiently expressed as soluble protein in E.coli BL21 (DE3). The purified rTgGAP45 remained its immunoreactivity to T. gondii infected human serum and mouse immune sera.

Toxicity of doxorubicin on Echinococcus granulosus protoscoleces in vitro

Chun-yan TIAN, Bei CHEN, Shuai LU, Li-mei WEN, Jun ZHAO, Xuan ZHENG, Kuerbannisha·AMAHONG, Yi GAO, Jian-hua WANG

2019, 37(5):  571-576.  doi:10.12140/j.issn.1000-7423.2019.05.011

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Objective To evaluate the toxicity of doxorubicin (Dox) on Echinococcus granulosus protoscoleces in vitro. Methods Total 200 E. granulosus protoscoleces in each group were incubated with different concentration of doxorubicin (25, 50, 100, 200, 400, 600 μmol/L) in triplicate for 24 hours in vitro. Other two groups were incubated with medium(blank) or 1% DMSO controls. The viability of protoscoleces was determined by eosin staining and survival rate was calculated. The structural damage of treated protoscoleces was observed under scanning electron microscope (SEM). Single cell gel electrophoresis was used to detect DNA damage in treated protoscoleces. Real-time quantitative PCR (qRT-PCR) was used to detect the mRNA expression levels of ataxia telangiectasia mutated gene (ATM), p53 and DNA topoisomerase 2-alpha (Topo2a) in treated protoscoleces. Results Based on the eosin dye staining, the survival rates of treated protoscoleces were (96.0 ± 1.4)%, (80.3 ± 4.8)%, (75.6 ± 6.2)%, (53.2 ± 3.0)%, (26.4 ± 8.1)% and 0 when the concentrations of Dox were 25, 50, 100, 200, 400, 600 μmol/L, respectively, compared to that of protoscoleces incubated with blank control [(99.0 ± 0.5)%] and 1% DMSO (98.6 ± 0.3)%], with significant difference when incubated concentration is over 25 μmol/L (P < 0.01). The Dox IC₅₀ on protoscoleces was (267.92 ± 7.14) μmol/L. SEM results showed that E. granulosus protoscoleces in the blank control group and 1% DMSO group had smooth surface with a spherical or elliptic shaped scolex and complete apical structure. There were clearly visible microtricles on the surface. When incubated with 400 μmol/L Dox, the protoscoleces scolex was distorted and damaged and whole body collapsed. The apical structure slightly distorted. The microtriches on the surface were lost obviously. The body surface was shrinked. The single cell gel electrophoresis showed trailed cell when the concentration of Dox reached to 100 μmol/L, indicating the cell damage. The olive tail moment (OTM) was 16.6 ± 1.7 for cells treated with 100 μmol/L of Dox, which was significantly longer compared with the blank control group(0.1 ± 0.0) (P < 0.01). The qRT-PCR results showed that the relative expressions of ATM, p53 and Topo2a mRNA in 1% DMSO group were 1.0 ± 0.1, 1.1 ± 0.1 and 1.3 ± 0.9, respectively, with no statistical significance compared with the blank control group (1.0 ± 0.1, 1.0 ± 0.4, 1.0 ± 0.1, respectively) (P > 0.05). However, the relative expression levels of ATM, p53 and Topo2a mRNA in Dox group were 38.6 ± 3.5, 10.0 ± 2.5 and 54.0 ± 0.8, respectively, which were significantly increased compared with the blank control group (P < 0.05). Conclusion Dox has toxicity on the protoscoleces of E. granuloides in vitro, leading to cell and DNA damage and rpossibly related to the mRNA expression of of ATM, p53 and Topo2a.

Epidemiological analysis of echinococcosis in Yunnan Province from 2012 to 2017

Ben-fu LI, Fang-wei WU, Xin-liu YAN, Jin-rong ZI, Jia PENG, Xue-ying BAO, Xuan CAI, Ya-ming YANG

2019, 37(5):  576-582.  doi:10.12140/j.issn.1000-7423.2019.05.012

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Objective To understand the endemic status of echinococcosis in Yunnan province so as to provide evidence basis for the better prevention and control of the disease. Methods Based on the National Hydatid Disease Epidemiological Investigation Program, epidemiological investigation of echinococcosis was performed in Deqin, Eryuan, Weixi and Shangri-La counties from 2012 to 2015, and in other 24 counties (Binchuan, Daguan, Dayao, Deqin, Eryuan, Fugong, Gongshan, Gucheng, Heqing, Huize, Jianchuan, Lanping, Longyang, Lushui, Mouding, Shilin, Tengchong, Weixi, Shangri-La, Xuanwei, Yangbi, Yulong, Yunlong and Zhaoyang) from 2016 to 2017. Three townships from each county and 4 villages from each township were selected as investigation sites based on cluster random sampling method. Residents with age over 1 year old were examined by abdominal ultrasonography in 2012, 2016 and 2017. The diagnosis of hydatid disease was made based on the ultrasonic imaging combining with epidemiological history, clinical manifestations and serological test for those suspected. During the investigation from 2013 to 2015, residents with age over 1 year old and all students from one primary school in each county were chosen for testing anti-Echinococcosus IgG antibody in their sera. Those with antibody positive were further examined by abdomanal ultrasonography to confirm the diagnosis. A questionnaire investigation was carried out in enrolled participants for the awareness of infection and prevention of hydatid disease. Each dog was selected from 20 households in each village for detecting the coproantigen of Echinococcus by ELISA. In each county (city), visceral organs were collected from locally raised sheep/pigs (100) or cattle (500) for examining hydatid cysts by necropsy. All data were statistically analyzed using SPSS 17.0 software. Results A total of 768 villages were investigated including 192 villages in 4 counties from 2012 to 2015 and 576 villages in 24 counties from 2016 to 2017. A total of 105 555 residents were examined by ultrasound, of whom 67 (0.06%) were detected with hydatid disease, all infected with Echinococcus granulosus. The prevalence of cystic echinococcosis in the investigated population in 2012, 2016 and 2017 were 0.05% (4/7 512), 0.05% (32/61 110) and 0.08% (31/36 933), respectively. Among the different investigated countries, the prevalence > 0.10% was distributed in Heqing (0.19%, 7/3 779), Shilin (0.17%, 8/4 799), Zhaoyang (0.16%, 4/2 520), Dayao (0.12%, 4/3 378), Eryuan (0.11%, 11/9 738), Yunlong (0.11%, 5/4 465) and Jianchuan (0.11%, 5/4 595). The prevalence of cystic echinococcosis in males and females were 0.05% (23/46 179) and 0.07% (44/59 376), respectively (P > 0.05). The prevalence increased with age (χ² = 21.414, P < 0.05), with highest in group of 60-79 years old (0.12%, 26/22 724) followed by people with age over 80s (0.08%, 2/2 414). There was a significant difference in prevalence among the different occupations (χ² = 11.581, P < 0.05), with highest prevalence in farmers and herdsmen (0.08%, 64/82 978). As to the education level, the prevalence was highest in the people with illiteracy (0.11%, 26/22 724) with significant difference compared to people with higher educational levels (χ² = 16.307, P < 0.05). The overall dog coproantigen positive rate was 4.87% (965/19 812), The dog positive rate > 5% was located in Longyang District (8.41%), Shangri-La City (8.13%), Lushui County (7.21%), Eryuan County (7.50%), Fugong County (6.54%) and Muding County (5.18%), with statistical difference among different counties(χ² = 69.287, P < 0.05). From 2012-2017, the average dog coproantigen positive rates in these investigated sites was 1.24% (16/1 293), 13.41% (483/3 601), 5.10% (95/1 862), 3.01% (72/2 389), 1.56% (103/6 588) and 4.81% (196/4 079), respectively. The overall hydatid detection rate in livestock (sheep, cattle and pigs) was 0.12% （32/27 502）, with 1.49% (2/134) in 2015, 0.21% (8/3871) in 2016 and 0.10% (22/21 125) in 2017. The overall awareness rate for echinococcosis among the investigated population was 52.39% (9 974/19 039), 47.72% (607/1 272), 51.77% (789/1 524), 61.00% (549/900), 77.20% (772/1 000), 43.50% (5 075/11 668) and 81.57% (2 182/2 675) from 2012 to 2017, respectively. Conclusion Echinococcosis in Yunnan Province showed a low and medium prevalence, all of which were infected with E. granulosus. Farmers and herdsmen over 40 years old with low educational level had the highest infection rate.

Prevalence of human intestinal protozoan infections in Sichuan Province in 2015

Jing-wen LUO, Hong-chun TIAN, Hong XIE, Bo ZHONG, Yang LIU, Yi-lan CHEN, Li LI

2019, 37(5):  583-587.  doi:10.12140/j.issn.1000-7423.2019.05.013

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Objective To understand the current status of human intestinal protozoan infections in Sichuan Province. Methods An epidemiological survey was carried out in Sichuan Province according to the Protocol of National Survey Scheme on Major Human Parasitic Diseases from April to June, 2015. Total 45 survey sites were selected from 15 counties (cities and districts) within 5 ecological zones of Sichuan by using a stratified sampling method. No less than 250 rural permanent villagers in each site were enrolled in the survey and the fecal sample was collected from each participant. The protozoan cysts in the feces were examined by Lugol’s iodine staining method(one check for each sample). The protozoan trophozoites were examined only in the fresh diarrheal or bloody fecal samples using saline direct smear method(one check for each sample). Each fecal sample was examined once. SPSS 23.0 software was used for statistical analysis. The prevalence difference among the different groups of people was compared by χ² test. Results Total 11 403 people were investigated. The overall prevalence of intestinal protozoan infections was 2.0% (223/11 403) province-wide. Total 9 protozoan species were identified in infected people including Entamoeba histolytica (0.2%, 22/11 403), E. coli (0.7%, 78/11 403), Gardia lamblia (0.1%, 9/11 403）, Blastocystis hominis (0.5%, 60/11 403）, E. hartmani (0.2%, 17/11 403）and Endolimax nana(0.6%, 67/11 403). Two cases of Balantidium coli, one case of each Iodamoeba butschlii and Embadomonas intestinalis were identified. The highest prevalence of intestinal protozoan infections was identified in areas of Source of rivers-Southern Gansu ecological zone (6.5%, 148/2 278),and the lowest prevalence was identified in Sichuan basin zone (0.4%, 10/2 289). There was a significant difference in the prevalence of protozoan infections among different ecological zones (P < 0.01). The highest prevalence of intestinal protozoan infections was identified in Markam County (10.2%, 102/1 001), followed by Ganzi County (6.1%, 46/755). There was significant difference in the prevalence of intestinal protozoa among different counties (cities and districts) (P < 0.01). The prevalence of intestinal protozoa in males and females were 1.9% (97/5 247) and 2.1% (126/6 156), respectively, without significant difference (P > 0.05). People with age 20-29 had the highest prevalence of intestinal protozoa and no protozoa infection was found in people with age of 80 or older, however, there was no significant difference in the prevalence of intestinal protozoa among different age groups (P > 0.05). Regarding the education, people with no education (illiteracy) had the highest prevalence (3.2%, 73/2 317) and no infection was identified in people with education of college and above, with significant difference among people with different education(P < 0.01). In terms of occupation, the highest prevalence of protozoan infections occurred in herdsmen (4.8%, 20/421) followed by students (2.0%, 30/1 491), however, there was no significant difference in the prevalence among different occupations (P > 0.05). In terms of ethnic groups, the highest prevalence was found in Tibetan population (5.3%, 149/2 381) followed by Han population (0.9%, 74/7 857) with significant difference in the prevalence of protozoan infections among different nationalities (P < 0.01). Conclusion Source of rivers Gannan ecological zone and Markam County kept relatively high prevalence of protozoan infections in which more prevention and control measures should be adopted. The people with low education and Tibetan are the main population for the control of intestinal protozoan infections.

Neurotoxicity of niclosamide on juvenile zebrafish

Bi-ran ZHU, Bo LI, Qiu-zhen FENG, Yun-dan XU

2019, 37(5):  588-592.  doi:10.12140/j.issn.1000-7423.2019.05.014

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Objective To study the neurotoxicity of niclosamide (NIC) on juvenile zebrafish. Methods Taking the model animal zebrafish as the research object, 7 200 fertilized zebrafish eggs were randomly divided into 6 groups with each four replicates and exposed in water containing 0, 5, 10, 20, 40 and 80 μg/L of NIC, respectively, for 120 hours. The rates of survival, malformation, hatchingand and body mass of juvenile zebrafish were measured. The acetylcholinesterase (AChE) activity of each group of fish was determined using an AChE Activity Kit. The average moving speed of juvenile zebrafish was monitored using a ZebraLab monitor system. The mRNA relative expression of mircroglobulin precursor (mbp) and α-tubulin in fish exposed to different concentration of NIC was determined by qRT-PCR. The results were statistically analyzed using one-way ANOVA followed by Tukey’s multiple comparison using SPSS 16.0. Results The survival of zebrafish were significantly reduced when exposed in water containing 40 μg/L NIC [(81.9 ± 0.8)%] and 80 μg/L NIC [(80.5 ± 0.9)%] compared to the water without NIC [(86.8 ± 0.2)%] (P < 0.05, P < 0.01, respectively). The malformation were significantly increased in water containing 40 and 80 μg/L NIC [(5.7 ± 0.6)% and (6.0 ± 0.4)%], respectively compared to water with 0 μg/L NIC [(3.2 ± 0.3)%] (P < 0.05, P < 0.01, respectively). The hatching and body mass of zebrafish were not significantly altered in all NIC exposure groups compared to 0 μg/L NIC exposure group [(92.2 ± 2.2) % and (472 ± 45 ) ng] (P > 0.05). The AChE activity in zebrafish exposed to 40 and 80 μg/L NIC was significantly increased [1 048.6 and 1 202.4 nmol/(mg·min), respectively] compared to fish in water without NIC[838.4 nmol/(mg·min)] (P < 0.05, P < 0.01, respectively). The moving speed of zebrafish in dark environment was significantly decreased in water containing 40 μg/L NIC [(2.3 ± 0.2) mm/s] and 80 μg/L NIC [(2.1 ± 0.2) mm/s] compared to water without NIC [(2.7 ± 0.2) mm/s]. In the bright environment the moving speed of zebrafish was also significantly decreased when exposed to 40 and 80 μg/L NIC water [(1.5 ± 0.1) mm/s, (1.4 ± 0.1) mm/s, respectively] compared to fish in water with 0 μg/L NIC [(1.9 ± 0.1) mm/s] (P < 0.05, P < 0.01, respectively). Compared to the fish in water without NIC (1.0 ± 0.0), the mRNA relative expression of mbp and α-tubulin were significantly down-regulated in fish exposed to 40 and 80 μg/L NIC (0.8 ± 0.1, 0.7 ± 0.1 and 0.7 ± 0.1, 0.6 ± 0.1, respectively) (P < 0.05, P < 0.01). Conclusion Exposure to 40 and 80 μg/L NIC could cause significant toxicity to zebrafish indicated by the decreased survival, moving speed and mbp and α-tubulin mRNA expression, and increased malformation and AChE activity.

INFORMATION REPORT

Analysis on the highly cited papers published in Chinese Jourmal of Parasitology and Parasitic Diseases since its inception

Feng-yun YI, Zheng-yan ZHANG, Qin CHEN, Fan YANG, Hui-feng SHENG

2019, 37(5):  593-597.  doi:10.12140/j.issn.1000-7423.2019.05.015

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To evaluate and improve the quality of Chinese Journal of Parasitology and Parasitic Diseases (CJPPD), the highly cited papers published in CJPPD from 1983 to 2018 were searched through the full-text database of Chinese journals in Chinese Academic Journal Network Publishing Database and the Chinese Citation Database of CNKI. Total 515 highly cited papers with more than 15 citations were identified from CJPPD since 1983. The publication time, authorship, covered parasite and research categories of these highly cited papers were analyzed using bibliometric method. The results showed that the 515 highly cited papers had been cited for 15 496 citations, with average of 30 citations for each paper. The research related to schistosomiasis covered the highest number of the highly cited papers, accounting for 27.6% (142/515). Most of the highly cited papers are associated with immunology and diagnosis of parasitic diseases, accounting for 75.6% (166/515). Among the 515 highly cited papers, only 27 were single-authored papers and others were co-authored (94.8%, 488/515). The analysis on the highly cited papers published in CJPPD reveals the research trends in the area of parasitology and parasitic diseases, objectively reflects the research dynamics and hotspots related to the control of parasitic diseases. The analysis also provides reference for researchers to grasp the research direction, for journal editors to make better editorial planning and topic selection.

REVIEWS

Progress in the identification of Paragonimus species by DNA technology

Kun-min HU, Bin ZHENG, Shao-hong CHEN, Ling AI

2019, 37(5):  598-602.  doi:10.12140/j.issn.1000-7423.2019.05.016

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Paragonimiasis is an important food-borne parasitic disease caused by the infection of Paragonimus spp. through ingestion of the intermediate host crabs, crayfishes contaminated with Paragonimus larvae. The tremotode parasitizes in different tissues and organs of human and other mammals and cause paragonimiasis. China is the country with the most widespread of the disease and diverse species of Paragonimus. Paragonimus infections have been reported in 27 provinces or regions in China. In recent years, the development of molecular biology technology including DNA detection technique has played an important role in the identification of Paragonimus species and strains. However, different DNA detection assays own different detection sensitivity, specificity, detection time and cost. The appropriate DNA detection method should be selected according to the different needs. In this paper, the research progress in the identification of Paragonimus species and strains by the DNA detection assays developed by domestic and international scientists is reviewed in order to provide reference for accelerating the identification Paragonimus species and the diagnosis of paragonimiasis.

Progress towards mosquito microbiome on regulating the transmission of mosquito-borne diseases

Zhen CAI, Xi YU, Gong CHENG

2019, 37(5):  603-608.  doi:10.12140/j.issn.1000-7423.2019.05.017

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Mosquito is a hematophagous insect which transmits malaria, dengue fever or Zika infections by blood feeding, posing fatal threats to global public health. Mosquito midgut is the first line of defense against infected pathogens. When mosquito feeds on a host with virus or parasite infections, the pathogens in the host blood are ingested into the midgut in which variant commensal microbes harbor. Some commensal microbes have effect on the infection of ingested pathgens into epithelial cells of mosquito midgut by secreting some proteins or other molecules, thereby regulating the process of pathogen transmission in the mosquito. In this review, we summarize research on the commensal microbes that regulate the transmission of mosquito-borne diseases and understand various mechanisms of commensal microbes involved in the transmission of mosquito-borne pathogens.

SHORT COMMUNICATIONS

Prevalence of soil-transmitted nematodes in Xiamen region during 2012-2017

Zhi-nan GUO, Min CHEN, Hua-fang CHEN, Guo-wei CHEN

2019, 37(5):  567-570.  doi:10.12140/j.issn.1000-7423.2019.05.018

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To understand the current status of the soil-transmitted nematode (STN) infections among Xiamen population in order to establish a scientific strategy for the better control and prevention, an epidemiological survey was performed in Xiamen region from 2012 to 2017. Based on the National Survey Plan and Implementation Rules for the Status of Human Key Parasites, the survey sites were chosen using stratified cluster sampling method. Total 4 evenly distributed townships (or street) were randomly chosen from each District of Xiamen (Out of island: Xiang’an, Tong’an, Jimei, and Haicang. On the island: Huli and Siming) and then four to five villages or communities were randomly selected from each selected township (or street) as survey sites. More than 50 permanent residents with age over 3 years old from each survey site were enrolled as participants. Fecal samples were collected from each participant and the intestinal helminth eggs were examined under microscope using modified Kato-Katz thick smear method (one sample one examination). Total 7 099 individuals from 140 survey sites (villages or communities) distributed in 28 township (streets) were examined. The overall prevalence of STN infections was 1.65% (117/7 099), including 1.62% (115/7 099) of hookworm infection and 0.03% (2/7 099) of Trichuris trichiura infection. No Ascaris infection was detected among all samples. There was no significant difference in the prevalence of STN between male (1.55%, 51/3 363） and female participants (1.77%, 66/3 736) (P > 0.05). In terms of the age, people over 50 years old had the highest prevalence of STN infections(3.83%, 84/2 196) with significant difference compared to people in other age groups (P < 0.05). Regarding the occupational distribution, farmers had the highest prevalence (4.95%, 87/1 756). There was significant difference in the prevalence of STNs between people living on the island (with only hookworm infection 0.25%, 5/2 035) and outside the island (mainland) (2.21%, 112/5 063, including hookworm 2.17%, 110/5 063 and Trichuris 0.04%, 2/5 063） (P < 0.05). People living in Xiang’an District had the highest prevalence of STNs compared to other 5 Districts. By this survey, we conclude that the overall prevalence of STN infections among the whole Xiamen region keeps at low level. People living on mainland have higher infection rate than people living on the island.

Survey of soil-transmitted nematode infection in Hangzhou from 2015 to 2018

Xing-yi JIN, Su-juan ZHU, Wei-min XU, Wei-qiang WANG, Heng WANG, Yi TANG, Liang-liang HUO, Yang YANG

2019, 37(5):  608-611.  doi:10.12140/j.issn.1000-7423.2019.05.019

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To understand the prevalence of soil-transmitted nematode (STN) infection in Zhejiang Province, a survey was carried out in Jiande city, a fixed monitoring site and in Xiaoshan, Fuyang, Linan Districts, Tonglu, Chun’an Counties, the five mobile monitoring sites of STN infections from 2015 to 2018 according to the requirements of Zhejiang Surveillance Plan and Implementing Approaches of STN. A total of 7 911 residents were enrolled in the survey, 145 of them were positive for STN infections and the infection rate was 1.83%. Among them, 4 cases were infected with Ascaris lumbricoides and Truchuris trichiura, and 137 cases were infected with hookworm. Enterobius vermicularis was not detected. The overall prevalence of STN decreased from 2.32% (89/3 829) in 2015 to 0.54% (11/2 044) in 2018, with a decrease rate of 76.72%. Hookworm larvae were cultured from 137 hookworm egg positive feces using test-tube filter paper culture method, 98 of them were larva-positive (71.53%). In which 80 cases were infected with Necator americanus, 13 cases with Ancylostoma duodenale and 5 cases were fixed infections. The infection rates of STN for male and female were 2.00% (77/3 845) and 1.67% (68/4 066), respectively. The highest infection rate was 3.20% (101/3 156) in the age group over 60, and the infection rate increased with age (χ² = 63.061, P < 0.01). With respect of education and occupational distribution, the highest prevalence of STN infection was found in students in junior middle school (2.07%, 48/2 313) and in farmers (2.13%, 144/6 763). Among 100 examined soil samples, the detection rate of A. lumbricoides eggs was 2.00% (2/100), and no hookworm larva was detected. From 2015 to 2018, the infection rate of STN in monitoring sites in Hangzhou showed a downward trend.

Survey on malaria prevention and control among abroad labor workers dispatched by two companies in Guizhou Province

Li-dan LU, Dong AN, Yang LI, Shan CAI, Jia-rui DAI

2019, 37(5):  612-615.  doi:10.12140/j.issn.1000-7423.2019.05.020

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To understand the situation of malaria prevention and control implemented among abroad labor workers as reference for the better control and management of imported malaria, a questionnaire survey was carried out in 2017 on those who returned from abroad or will be dispatched abroad and the administrators in these two companies in Guizhou Province for the knowledge, attitude and behavior (KAP) toward malaria infection and control. Among 242 people surveyed, 182 (75.2%) had experience working abroad, of which 40 (22.0%) had suffered from malaria. Among these migrant workers, the infection incidence of malaria was highest in those with education of middle school or lower (44.4%), with statistical significance among people with different educational levels (P < 0.05). People who worked outdoor had higher malaria incidence (34.5%) than those working indoor with statistical significance (P < 0.05). However, there was no statistical significance in the malaria incidence between the people with acquired malaria control knowledge and without (P > 0.05). People who agreed that antimalarial drugs could prevent malaria had significantly lower malaria incidence (15.7%) than those who did not agree (42.9%)(P < 0.05). Regarding the protection behavior, people who used mosquito nets had much lower malaria incidence (1.4%) than those who did not (35.8%) with statistical significance between them (P < 0.05). The similar result was seen in the usage of mosquito repellents, people who used had significantly lower malaria incidence (12.1%) than those who did not (27.3%)(P < 0.05). People who took prophylactic medication had significantly lower malaria incidence (13.0%) than those who did not (59.0%) (P < 0.05). Multivariate logistic regression analysis demonstrated that the risk factors for malaria infection include the lack of use of mosquito nets (OR = 69.075, CI = 7.187-663.904), lack of taking preventive medicine (OR = 17.602, CI = 4.754-65.173). The attitude towards agreement to use anti-malarial drugs was beneficial for preventing malaria (OR = 0.119, CI = 0.034-0.423). Lack of mosquito net usage and without taking preventive medicine are the big risk factors for malaria infection in endemic areas when working abroad.

An investigation of parasitic infections in aquatic products sold in Qiqihar

Ze-hu SHENG, Shuo ZHANG, Jin-biao YAO, Fan ZHANG, Guan-bei LI, Jia GUO, Hao ZHANG

2019, 37(5):  616-618.  doi:10.12140/j.issn.1000-7423.2019.05.021

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In order to know the infection status of parasite in aquatic products sold in Qiqihar, 14 species of freshwater fishes, molluscs, arthropods and amphibians were collected from this area during August to November, 2018. Fish samples were examined for trematode metacercaria by direct slide examination under microscope. The parasite species were identified under microscope. In this survey, Total 450 fishes within 7 species were examined, 32.4% of them were infected with different trematode metacercaria. Total five species of trematode metacercaria were identified including Clonorchis sinensis, Metorchis taiwanensis, Metagonimus yokogawai and Metorchis taiwanensis and one unknown. The infection rates of trematode metacercaria in 7 species of freshwater fish were Phoxinus lagowskii (75.3%), Carassius auratus (42.2%), Perccottus glenii (24.5%), Pseudorasbora parva (23.6%), Cyprinus carpio (4.8%), Hemiculter leucisculus (4.4%) and Pseudobagrus fulvidraco (0). In molluscs, the infection rates of trematode in Procambarus clarkii and Unionidae were 8.3% (7/84) and 15.0% (3/20). The total infection rate of helminth in frog Rana nigromaculata was 42.9% with trematode Diplodiscus mehrai and an unknown nematode identified in its intestine. No parasite was identified in Lithobates catesbeiana, Macrobranchium nipponense, Brachyura and Oratosquilla oratoria. The survey showed that it is common to find the helminth infections in the aquatic products sold in Qiqihar area and people and local CDC should pay attention to the food safety.

Epidemiological analysis of malaria in Henan Province during 2016-2018

Cheng-yun YANG, Dan QIAN, De-ling LU, Ying LIU, Rui-min ZHOU, Su-hua LI, Hong-wei ZHANG, Yu-ling ZHAO

2019, 37(5):  619-622.  doi:10.12140/j.issn.1000-7423.2019.05.022

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To analyze the epidemiological characteristics of malaria in Henan Province as basis for the better prevention and control, the information of malaria cases reported in Henan Province during 2016-2018 were collected and analyzed for the infected Plasmodium species and source, distribution of infected cases, diagnosis and treatment using SPSS 17.0. The results showed that total 541 malaria cases were reported in Henan Province during 2016-2018. These laboratory confirmed cases consisted of 405 cases(74.8%) infected with Plasmodium falciparum, 36 (6.7%) with P. vivax, 76 (14.1%) with P. ovale, 16 (2.9%) with P. malariae, 7 (1.3%) with mixed infections, and 1 (0.2%) with P. knowlesi. All cases were imported from Africa and Southeast Asia except for one case domestically imported from Yunnan in 2016. The imported cases came mainly from Angola (90), Nigeria (71), Congo (44), Cameroon (31), Ghana (29), Guinea (28), Côte d′Ivoire (26), The Republic of Congo (25), and Equatorial Guinea (23). The malaria cases were reported in all 18 cities with most in Luoyang (83), Zhengzhou (77), Xinxiang (53), Puyang (40), Anyang (33) and Xuchang (31). Most malaria cases were male (533, 98.5%), and only 8 cases were female (1.5%). The cases covered the age ranged from 18 to 71 years old, most of them were 30-50 years old (350 cases, 64.7%). Regarding the occupation, most of the infected cases were farmers(223 cases, 41.2%), followed by workers(78 cases, 14.4%), household or unemployed(62 cases, 11.5%). The cases were reported all year round with more in May, August and December. The time between disease onset to visiting a doctor varied from 0 day to 154 days with average of 2.6 days. Total 208 (38.4%) cases were diagnosed as malaria within 24 hours after visiting a doctor, 196 (36.2%) within 3 days, 137 (25.3%) over 3 days and 66 cases (12.2%) were diagnosed as malaria over 7 days after a doctor visit. The local hospitals were the preferred medical institutions for patients to seek for medication after onset of the disease (405 cases, 74.9%), followed by the local center for disease control and prevention(126 cases, 23.3%). Total 345(63.8%) cases received confirmed diagnosis of malaria at the first doctor visit. The medical institutions to get confirmed diagnosis of malaria were mainly provincial (187 cases, 34.6%) and prefecture-level medical institutions (178 cases, 32.9%).

Activities of host animals of Echinococcus spp observed by infrared triggered cameras in Shiqu, Sichuan

Qi WANG, Shun-de CHEN, Qian WANG, Wei HE, Wen-jie YU, Guang-jia ZHANG, Fan CHEN, Liu YANG, Sha LIAO, Rui-rui Li, Yan HUANG, Ren-xin YAO, Bo ZHONG

2019, 37(5):  622-625.  doi:10.12140/j.issn.1000-7423.2019.05.023

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To understand the activities of intermediate and definitive host animals of Echinococcus spp. in Shiqu, Sichuan during June to August 2018, the infrared triggered cameras were used to observe the interaction between human and dogs, and dogs with other animals, within eight households in Rizha village, Odoma township, Shiqu County, Sichuan. Other four sites were selected to observe the activities of small mammals around the selected households. The infrared cameras were installed on poles or fence about 100 cm above the ground to record the activities of people or animals within the range of 6 m. The rodents Ochotona curzoniae and Neodon fuscus within the camera monitor range were collected for the species identification by PCR amplification of cytochrome b gene (Cyt b) and double-stranded DNA sequencing. Total 277 minutes of video were effectively recorded from 3 out of 8 households. The records showed that there was only one leashed Tibetan dog in each household, which moved outside the fence, but within 28 m of house. The dogs were fed once a day averagely. There was no touch caught between people and domestic or wild dogs. The rodents captured by the camera were identified as Ochotona curzoniae and Neodon fuscus by DNA sequencing analysis. The ground activity of Ochotona curzoniae started at 6 : 46 and ended at 20 : 41 with peak at 9 : 00, 12 : 00, 15 : 00 and 19 : 00. The smokey vole Neodon fuscus started to move around at 8 : 06 and ended at 20 : 09 with peak at 19 : 00. Ochotona curzoniae activity began earlier than Neodon fuscus and was aremore active observed throughout the day. The only interaction between dogs and their owners was when dogs were fed. If dogs are fed less, more chance the dogs would prey on small mammals.