Effect of integrated control intervention on soil-transmitted helminth infections in Jiangxi province in southeast China.

Soil transmitted helminths (STHs) burden was enormous in China several decades ago, however, rigorous control efforts have been successful with appreciable reduction in diseases burden. Here, we assessed provincial-level data derived from cross sectional surveys, executed in 1989, 2002 and 2014, on the prevalence of STHs among populations in Jiangxi province, China. This study, also, reported STHs integrated control intervention aimed at reducing STHs transmission and worm burden among population at county-level. The intervention strategies included mass drug administration (MDA), health education, improved water supply for drinking, improved sanitary facilities and environmental modification in Guixi municipality. The overall infection rate of STHs in Jiangxi province decreased from 77.7% (1989) to 6.3% (2014), while Ascaris lumbricoides, hookworm and Trichuris trichiura decreased from 71.1%, 17.6% and 17.0% (1989) to 0.9%, 4.7% and 1.0% (2014), respectively. STHs infection rates in female population were higher than male in the three surveys. Reduction in STHs prevalence was observed in all age groups, but the decline was less in higher age group. STHs prevalence in Guixi intervention region indicated remarkable reduction from 31.8% (2006) to 6.1% (2009) (χ2＝255.22, P＜0.01). A. lumbricoides, hookworm and T. trichiura infection rates decreased from 10.4%, 17.0% and 7.1% (2006) to 0.1%, 4.1% and 2.2%, respectively (2009) (X2A.l = 110.23, P<0.01; X2hk = 103.57, P < 0.01; X2T.t = 32.0, P < 0.01). A. lumbricoides infection rate declined the most of all STHs. Following control efforts with integrated control intervention strategies, STHs prevalence in Jiangxi province experienced remarkable trend in decline between 1989 and 2014. Consolidating control efforts with sustained integrated control strategies is, therefore, important to achieving STHs elimination in China.

[Preservation of live eggs of Schistosoma japonicum].

OBJECTIVE: To observe the preservation time and activity of miracidium hatching from schistosome eggs preserved in different solutions, so as to obtain the optimal preservation conditions and then provide quality control products for field application. METHODS: The rectum stool of rabbits infected with Schistosoma japonicum was collected and the coarse fecal residue was removed with a series of sample sieves of 80, 100, 160 and 200 meshes respectively, and then the schistosome eggs were concentrated with the sample sieve of 260 meshes. The concentrated eggs were preserved in 0.9% sodium chloride solution, 1.2% sodium chloride solution, phosphate buffered saline solution (PBS, PH 7.2), 1.0% sucrose solution, and Mili-Q water, respectively, and then were conserved in a 4 °C refrigerator and 15 °C constant temperature incubator, respectively. The preserved eggs were hatched in different time (7-day interval) , the vitality and quantity of the miracidia were observed, and the hatching rates were calculated. RESULTS: Under the condition of 4 °C, the hatching rates of eggs dropped to 0 in 1.0% sucrose solution and 1.2% sodium chloride solution at the 49th and 126th day, respectively, and the hatching rates of eggs in the 0.9% sodium chloride solution and PBS solution dropped to 10% at the 112th day, and the activity of miracidium was weakened since 140th. In the Mili-Q water, the hatching rate dropped less than 10% at the 196th day and the activity of miracidia was weakened since the 280th day. Under the condition of 15 °C, the hatching rate of eggs in different solutions gradually dropped to 0 from the 49th day to 105th day. CONCLUSION: The eggs preserved in Mili-Q water at the temperature of 4 °C can be used as the positive reference for hatching tests within 196 days.

[Survey of epidemic status of principal human parasites in Jiangxi Province in 2014].

OBJECTIVE: To understand and analyze the epidemic status of principal human parasites in Jiangxi Province, so as to provide the evidence for formulating The 13rd Five-Year Project of Parasites Control. METHODS: A survey was performed according to the scheme of The 3rd National Survey of Principal Human Parasites as well as the specific situation of Jiangxi Province. The survey of the soil-transmitted nematodes and intestinal protozoa were performed based on the ecological regions and stratified by economic and geographic situation. The survey of Clonorchis sinensis was performed along with the soil-transmitted nematodes in rural, and was performed by the sample method of random cluster in cities and towns. RESULTS: Totally 23 606 residents of 92 survey sites from 32 counties were surveyed, all of them were tested for the infection of soil-transmitted nematodes, in which 21,569 residents were tested for intestinal protozoa infection, and 1 486 children were tested for eggs of Enterobius vermicularis. Twenty kinds of intestinal parasites were found, with the total infection rate of 9.64%, and 4.296 millions of patients were reckoned in the whole Jiangxi Province. The infection rate of children of E. vermicularis was 13.73%. The infection rates of C. sinensis and intestinal protozoa were 0.58% and 1.42% respectively. The infection rate of Toxoplasma gondii was 7.50%. CONCLUSION: In Jiangxi Province, the infection rates of soil-transmitted nematodes are decreasing but the infection rate of C. sinensis is increasing in local areas, and the control work of parasites still should be strengthened.

[Analysis of characteristics of schistosome cercarial infested water contacts of residents in Poyang Lake endemic areas after operation of Three Gorges Project].

OBJECTIVE: To understand the characteristics of schistosome cercarial infested water contact of residents in Poyang Lake endemic areas after the operation of Three Gorges Project, so as to provide the evidence for formulating a well-directed control strategy. METHODS: The residents in two villages in schistosomiasis endemic areas were selected and surveyed for their activities of infested water contacts by questionnaire. RESULTS: The proportion and frequency of infested water contacts of residents in Poyang Lake region were high and the average rate of infested water contacts was 69.77%, and 98.96% of infested water contacts occurred in spring, summer and autumn. The main ways of infested water contacts were fishing/swimming/playing for adult men, washing clothes/fishing for adult women, and swimming/playing for school children, respectively. The rates of infested water contacts were 73.33%, 71.63% and 61.87% in adult men, women and school children, respectively. The frequencies of infested water contacts > 1 time/week, 1 time/week-1 time/month, and < 1 time/month were 62.61%, 23.74% and 13.66% respectively. CONCLUSIONS: The infested water contacts mainly occurs in spring, summer and autumn, and the main way of infested water contacts was fishing. Farming and mowing grass, which had been the primary way, now become the secondary way for the adult residents.

[Investigation of infections of soil-transmitted nematodes in Fusheng Village of Poyang Lake area in Jiangxi Province].

OBJECTIVE: To understand the status of soil-transmitted nematode infections in Poyang Lake area in Jiangxi Province. METHODS: The parasitic eggs of stools of residents aged 6-65 years were detected with the Kato-Katz technique in Fusheng Village of Poyang Lake area in Jiangxi Province in 2008. RESULTS: In 2008, the total average infection rate of soil-transmitted nematodes was 37.97%, and the infection rates of Ascarid lumbricoid, Trichuris trichiura and hookworm were 20.39%, 6.67% and 18.45%, respectively. The total infection rate of soil-transmitted nematodes and the rate ofA. lumbricoid were higher in the female than in the male with a statistically significant difference (P < 0.01). The infection rates of T. trichiura and hookworm in the female were higher than those in the male, but there was no significant difference between them (P > 0.05). The total infection rate of soil-transmitted nematodes and the rate of hookworm in different age groups had a similar change pattern which had an increasing trend with the age growing. The infection rate ofA. lumbricoid was the lowest in the age group of 10-19 years and was the highest in the age group of 20-29 years, and then the rate showed a gradually declining trend with the age increasing. The infection rate of T. trichiura had a decreasing trend as the age grew with 2 peaks in the age groups of 10-19 and 40-49, respectively. CONCLUSIONS: The infection rates of soil-transmitted nematodes in population of Fusheng Village in Jiangxi Province are still high. The effective control measures include health education, regular anthelminthic treatment, innoxiously processing of stool and environment reform, and the interruption of the transmitting chain is the fundamental strategy.

[Development and assessment of Schistosoma japonicum antibody test kit (IHA)].

OBJECTIVE: To develop a Schistosoma japonicum antibody test kit (IHA). METHODS: According to the requirement of Good Manufacturing Practice (GMP) and Quality Control (QC) of drugs, the components of kit as well as its preparation method and procedure were studied, and the test kit was assembled and its diagnostic effect was assessed. RESULTS: The sensitivity and specificity were up to 94.49% and 97.14% when testing the serum samples of chronic schistosomiasis patients and normal serum samples by the kit, respectively. The Youden Index of the Kit was 0.92. The cross reaction rates with paragonimus and trichina were 15.00% and 10.00%, respectively. Compared with ELISA and another IHA kit produced by An'Ji company which were used to test schistosome antibody in residents of endemic areas at the same time, the coincident rates of the developed kit were 93.06% and 92.25%, respectively. CONCLUSION: The IHA kit for Schistosomajaponicum antibody has a high sensitivity and specificity, and has the value of application and popularization in the field.

[Evaluation on medium-term effect of schistosomiasis comprehensive control strategy based on infectious source control in Poyang Lake area].

OBJECTIVE: To evaluate the medium-term effect and stability of the schistosomiasis comprehensive control strategy based on infectious source control after its popularization and application in marshland endemic areas. METHODS: The schistosomiasis comprehensive control strategy based on infectious source control including "replacing buffalo with machine", "marshlands isolation and grazing forbidden", etc. was implemented in all villages of Sanli Township, a heavy endemic area with schistosomiasis in Jianxian County. The infection situation of schistosomiasis in population and Oncomelania snails in 4 villages around the lake were monitored regularly for 6 consecutive years. RESULTS: The infection rate of schistosomiasis in population significantly decreased after the comprehensive control measures were carried out. Two years later, the infection rate in Huangjia Village was 0, and was sustained at zero for 5 consecutive years; the infection rate in Fengfu Village decreased by 77.24% and stabilized to zero for the next three years; the population infection rates in Fanrong Village and Caomen Village decreased by 82.33% and 82.53%, respectively, then the infection rates of the two villages kept under 1% and were 0 for 2 years and 1 year, respectively. The number of spots with infected snails in two marshlands in pilot areas decreased yearly from 10 before the intervention to 0, in which, the infection rate of snails and the number of spots with infected snails in Huangjiaoniu Marshland and Goulian Marshland decreased to zero 1 year and 3 years after the strategy was implemented, respectively, and the infected snails were not found in these marshlands in following years. CONCLUSION: Strengthening the management of buffaloes in surrounding areas and utilizing marshland resources is the main measure that can consolidate and expand the medium-term and long-term effect of the schistosomiasis 2.2 comprehensive strategy based on infectious source control.

A novel procedure for precise quantification of Schistosoma japonicum eggs in bovine feces.

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin-ethyl acetate sedimentation-digestion (FEA-SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.

[Comparison of fecal examinations and worm collection results in an investigation of Ascaris lumbricoides infection].

OBJECTIVE: To explore the relationship between fecal examinations and worm collection results in a community investigation of Ascaris lumbricoides infection. METHODS: A total of 1 019 residents in Zhangxi Village, Nanchang County, Jiangxi Province were investigated with the Kato-Katz technique and worm collection after deworming. RESULTS: Among 1 019 residents investigated, the actual prevalence of A. lumbricoides was 30.23%, and the egg and worm positive rates were 20.41% and 23.75%, respectively. The average burden was 2.64 worms per person, and the heavier worm burden accounted for less proportion. The heavier the worm burden, the higher the probability to got egg in the feces. If one person had 7 worms or more, the probability to got eggs in his feces was 100%. Among people of false negative fecal examination, 61.00% of them were infected with male worms only, whereas 7.00% were infected with immature female worms with or without male worms, and 32.00% were infected with mature female worms with or without male worms. Totally 32.47% of infected people were missed by fecal examination, including 22.08% without egg excreted, and 10.39% missed because of the method itself. CONCLUSION: The egg positive rate is obviously lower than the actual infection rate, and the egg detection rate is correlated with the worm burden.

[The effect and influencing factors of schistosomiasis control by forbidding livestock denaturing on marshland with Oncomelania snails].

OBJECTIVE: To evaluate the effect of schistosomiasis control by forbidding livestock denaturing on marshland with Oncomelania snails and to analyse its influencing factors. METHODS: The village of Aiguo, Xinhe, Huangjia, Fanrong, Fengfu and Caomen and its respective nearby marshland, i.e., Aiguoniu, Liulingwei, Huangjianiu, Da, Goulian, and Litouzui, in Jinxian county, Jiangxi province were selected as the pilot areas for implementing the measures of forbidding livestock denaturing on the marshlands with Oncomelania snails during the period of the year 2005 to 2007. A total of 300 residents in each village were randomly chosen for stool examination with the Kato-Katz technique every year. The snail survey was carried out in spring and autumn every year on the marshlands close to the villages with systemic sampling method. The marshlands with a height 16.5 m above the sea level in Futian was selected for snail survey and planting with sesame. The residents aged 20 - 50 years old in Fengfu and Aiguo villages were studied by using questionnaire on the compliance of forbidding livestock pasturing on marshlands with Oncomelania snails. RESULTS: Before implementation of the measures, human infection rate with Schistosoma japonicum was 11.35% (90/793) in Aiguo, 4.00% (12/300) in Xinhe, 4.00% (6/150) in Huangjia, 8.00% (12/150) in Fanrong, 3.17% (4/126) in Fengfu and 6.64% (14/211) in Caomen. After implementation in 2008, human schistsome infection rate in the aforementioned 6 villages was declined to 0.18% (1/551), 0.00% (0/348), 0.00% (0/316), 2.27% (7/308), 1.17% (5/428) and 1.16% (5/430), respectively. Only in Fengfu village the decline of the human prevalence was not significant (χ(2) = 2.4, P = 0.12), while in the other 5 villages, human prevalence rate had been declined significantly (χ(2) = 126.77, P < 0.01; χ(2) = 16.31, P < 0.01; χ(2) = 18.79, P < 0.01; χ(2) = 10.39, P < 0.01; χ(2) = 14.17, P < 0.01, respectively). Infected snails were not found in 5 out of the 6 marshlands close to the villages. Three infected snails were founded in Da marshland because of poor environmental isolation. Before planting, the living snail density was 0.063/0.11 m(2) (34/540), and after planting, the living snail density was 0.0074/0.11 m(2) (4/538), a 88.25% reduction (Z = 12.47, P < 0.01) was recorded through economy crop planting at Futiandaan marshland in 2008. A total of 986 pieces of questionnaire were provided, and 968 valid ones were collected. The results of questionnaire indicate that compliance of forbidding livestock denaturing on marshland with Oncomelania snails in Aiguo and Fengfu villages was 84.38% (216/256) and 75.42% (537/712), respectively. Using logistic regression model, knowledge level on harmfulness of livestock denaturing on marshland with Oncomelania snails, willingness of culture with machine to substitute traditional cattle culture, and willingness of investment to marshland culture development are 3 varieties that affect residents' implementation of forbidding livestock denaturing on marshland with Oncomelania snails. CONCLUSION: The infected snail density and human schistosome infection rate were reduced on the marshlands of well environmental isolation after 2 - 3 years implementation of forbidding livestock denaturing on marshlands with Oncomelania snails. The key influencing factors of forbidding livestock denaturing on marshland with Oncomelania snails are knowledge level on harmfulness of livestock denaturing on the snail infested marshlands, the willingness of machine culture to substitute cattle culture, and the willingness of investment to marshland culture development.

[The impact of water level changes on distribution of snails around lake areas reacted by thematic mapper images].

OBJECTIVE: To study the impact of water level changes on the distribution of snails around lakes, and to study the possibility of forecasting the distribution of snails according to changes of water level reacted by remote sensing images. METHODS: All information including water level information of Xingzi Hydrometric Station from 1997 to 2007, twelve TM images of Poyang Lake between 1998 and 2006 were collected. The water areas of Poyang Lake was extracted by MNDWI threshold approach, and the relationships between water areas from TM images and water level from Hydrometric Station was analyzed; Majiawan and Menqiantan marshland of Zhuxi village, Xingzi county was chosen as study pilot to set frames and investigate snails 2991 frames in 2007, and the information of snails of this pilot from 1998 to 2006 was collected to analyze the relationships between snails and water level. RESULTS: The water areas of Poyang Lake extracted from Remote Sensing images from 1998 to 2006 was 1658.73 - 5873.48 km(2), and the corresponding daily water level of Xingzi Hydrometric Station was 9.96 - 21.72 m, according to correlation analysis, they were positive correlation relationship, the correlation coefficient was 0.96 (P < 0.01), and build a model: S = 5189.96 x ln(h) - 10 284.97; the percent of frames with living snail of zhuxi pilot from 1998 - 2007 was 28.33% - 77.46%, the corresponding monthly average water level of last August was 13.19 - 21.96 m, the corresponding highest water level of last year was 15.97 - 21.96 m, according to correlation analysis. The percent of frames with living snail of zhuxi pilot was negatively correlated with the corresponding monthly average water level of last August and the corresponding highest water level of last year, and the correlation coefficient was -0.69 (P < 0.05), and -0.77 (P < 0.01) respectively. CONCLUSION: Water areas of Poyang Lake extracted from remote sensing images could well express the actual changes of water level, and the highest water level ahead of the year investigating snails influence the distribution of snails, thus we can estimate the distribution of snails around lakes by remote sensing images.

[Study of the efficacy of a monoclonal antibody biotin-avidin system for the diagnosis of schistosomiasis japonica].

OBJECTIVE: To explore the diagnostic efficiency of circulating antigen using the TM5.28 mAB-biotin-avidin system for the detection of schistosomiasis japonica. METHODS: A mAb-biotin-avidin system was set up using a TM5.28 mAB which was prepared against a gut associated antigen of Schistosoma japonicum. Detection was performed on the sera from 50 acute schistosomiasis patients, 224 chronic patients, 49 advanced patients and 46 schistosomiasis patients who were followed up at 6 months and 12 months post treatment. In addition, 19 cases of clonorchiasis, 31 cases of paragonimiasis, 23 cases of hepatitis B and 100 healthy individuals were also included. RESULTS: The system showed sensitivity of 83.1% and specificity of 94.0% when applied to detect chronic schistosomiasis and healthy persons respectively, while 94.0% to acute schistosomiasis. The Youden's index of the system was 0.771. The rate of cross-reaction to paragonimiasis, clonorchiasis and hepatitis B was 12.9%, 15.8% and 13.0% respectively. The rates of negative turning were 43.9% and 62.1% respectively in chronic schistosomiasis at the 6 month and 12 month intervals after treatment. Geometric mean of the OD values also decreased from 0.172 before treatment to 0.081 at 6 months and 0.068 at 12 months after treatment with a reduction rate of 60.30%. The detection rate in the heavy infected population reached a maximum of 90.0%. This was similar in moderate and light infected populations, i.e., 83.9% and 82.1%, respectively. CONCLUSION: The TM5.28 mAb-biotin-avidin system showed a relatively high efficiency in the diagnosis of schistosomiasis and a high negative turning rate after treatment. It is, therefore, a valuable tool for the estimation of prevalence in endemic populations, as well as individual diagnosis and for assessing the effect of chemotherapy.