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Objective To study the morphological change of Schistosoma japonicum eggs processed by calcium cyanamide synthetic drug,so as to provide the basis for further study of the mechanism that calcium cyanamide synthetic drug to schisto?some eggs. Methods The calcium cyanamide synthetic drug was added to the cattle feces containing schistosome eggs and mixed up,and then the cattle feces was stacked as original shape on the marshland. Blank controls were set at the same time. The cattle feces samples were collected and the schistosome eggs were observed under a microscope on the 1st,2nd,3rd,7th day after the experiment. Results By the effect of calcium cyanamide synthetic drug,the color of eggs was deepening gradual?ly,the miracidia were atrophied,and the shells of eggs were thickened. The embryonic membrane of miracidia was no longer completed 3 days later,and the miracidia were deformed severely 7 days later. The atrophy of miracidia was not obvious in the blank controls. Conclusion The schistosome miracidia and embryonic membrane can be damaged by the calcium cyanamide synthetic drug,and worse damaged with time extending.
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Objective To evaluate the schistosomiasis control effect of the measures of replacing cattle with machine for cul?tivation and forbidding depasturage of livestock on marshlands in marshland and lake regions. Methods The retrospective re?view and field survey were implemented in the Jiangling and Gongan counties of Hubei Province where were implemented with the measure of replacing cattle with machine for cultivation,and Yuanjiang and Huarong counties of Hunan Province where were implemented with the measure of forbidding the depasturage of livestock on marshlands. The schistosome infection status of hu?man,cattle,and Oncomelania hupensis snails,and schistosome?infested field excreta were surveyed from 2007 to 2013. The ef?fects of the interventions were compared before and after their implementations. Results The 6 villages of Hubei Province were implemented with the measure of replacing cattle with machine for cultivation,and 7 villages of Hunan Province were imple? mented with the measure of forbidding the depasturage of livestock on marshlands. From 2007 to 2013,the schistosome infection rates of residents declined from 3.95%to 0.70%(χ2 =128.376,P0.05). The infection rate of cattle decreased from 3.66%in 2007 to 0.65%in 2013,and the descend range was 82.24%(χ2=13.692,P<0.05). The field excreta was surveyed in the snail breeding place in 2013. The investigated area was 157.435 hm2, and 625 samples of field feces of cattle were collected with the density of field excreta of 3.97/hm2,and the positive rate was 1.12%(7/625). The schistosome infection rate of snails and the density of infected snails decreased successively from 2007, and no infected snails were detected from 2011 to 2013. Conclusions The schistosomiasis endemic situation are decreased sig?nificantly after the interventions of replacing cattle with machine for cultivation and forbidding the depasturage of livestock on marshlands. Therefore,schistosomiasis control effect of these measures is notable in the marshland and lake regions.
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Objective To analyze the time and space aggregation of acute schistosome infections in marshland and lake areas in five provinces(Jiangsu,Anhui,Jiangxi,Hubei and Hunan province)from 2005 to 2012,so as to provide the evidence for es-tablishing control strategies and taking effective control measures. Methods The data of patients with acute schistosome infection in marshland and lake areas in five provinces from 2005 to 2012 were collected and analyzed with the concentration ratio and circu-lar distribution methods for the epidemic season features and time aggregation of the infection,and with the spatial autocorrelation analysis for the space aggregation of the infected cases. Results According to the concentration ratio,the occurrence of acute schistosome infection had strong seasonality,and the concentration ratio was 0.758;according to the circular distribution method, the peak day of acute schistosome infections was 10th,August. The spatial analysis suggested that the infected cases highly gath-ered around Poyang Lake,Dongting Lake and Yangtze River Basin in 23 counties of the five provinces,and the result of spatial au-tocorrelation analysis showed that the spatial autocorrelation index I was 0.16(P=0.01). Conclusion The occurrence of acute schistosome infections in lake regions of the 5 provinces shows strong seasonality and space aggregation,therefore we can bring the control mark forward,and take targeted prevention and control measures in high aggregation areas of acute schistosomiasis.
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Objective To investigate the schistosomiasis japonica infection and preventive knowledge of immigration popula-tion in Jinshan District,Shanghai so as to provide the evidence for improving the control work. Methods The immigration popula-tion from schistosomiasis endemic provinces and local people were screened by serum IHA screening for schistosome infection, and the positives were further examined by Kato-Katz technique and the miracidium hatching method. The schistosomiasis preven-tive knowledge and behaviors were investigated by questionnaires. Results A total of 579 were investigated with 348 immigration people and 231 local people,and among them,the male accounted for 72.0%and female accounted for 28.0%. In the immigration population,the main age group was 20-29(56.0%),and 56.6%of the immigration had an education level at senior middle school or higher. The most proportion of immigration was from Anhui Province(36.2%). There were 4 IHA positive persons(1.15%)in the immigration,and 1 was positive in the stool test,and the schistosome infection rate was 0.29%. There were no positives in the local people. The schistosomiasis preventive knowledge of the immigration was generally poor,and some people’s behaviors of see doctor and medication were incorrect. Conclusion There are schistosome infected persons among the immigration population from schistosomiasis endemic provinces,and their schistosomiasis prevention knowledge was poor,thus there is a schistosomiasistransmission risk.
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Objective To observe the effects of calcium cyanamide (Rongbao) on the histological and morphological changes of Oncomelania hupensis snails in order to explore its molluscicidal mechanisms.Methods The serial snails' slides were fixed after soaking in a concentration of Rongbao leached liquor at different time.The histological and morphological changes of the snails were compared among these slides.Results After soaking in the Rongbao leached liquor for 48 h,the mantle epithelia,respiratory epithelia of the gill,liver cells,and muscle cells of gastropods were injured seriously,which resulted in the death of the snails directly.The death rates of the snails were 96.70% and 100% after soaking in the Rongbao leached liquor for 48 h and 72 h,respectively.Conclusion Rongbao is an effective molluscicide by damaging the several snail tissues.
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The paper reviewed the project management model and its evolution in the national schistosomiasis control in China at different stages.The key factors impacting the progress of the control activities were analyzed by introducing the concept of project management,and the principles,i.e.objective management,temporal management,cost-effectiveness management,and quality management,that would have to be complied with in the future control activities were put forward,so as to accelerate the elimination of schistosomiasis in China.
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Objective To understand the status of knowledge and attitude of schistosomiasis control among the human populafion in schistosomiasis transmission-controlled area of Changqiu mountainous areas.Methods The subjects were selected by the random cluster sampling method among residents and students in these alias,then they were investigated by questionnaire.Resuits A total of 150 residents and 209 students were selected.There were 60% of the residents whose awareness rates of the knowledge on schistosomiasis control were above 90%.The correction rates of the questions in residents were between 99.30% and 100%.and the awareness rates about the questionswhether re-infection would occure after schistosomiasis was cured and the remedy for schistosomiasisof female adults were both 75.40%.The correction rates of the two question8 on attitude and behaviour of schistosomiasis control in adults were above 80.00%.In students'questionnaires.the awareness rates of knowledge on schistosomiasis control were above 90%.except the two questions on the shape of the snailand the infection-risk months of schistosomiasis.The correction rates of attitude and behaviour of schistosomiasis control were aslo above 80%.Conclusion The correction rates of knowledge,attitude and behaviour of schistosomiasis control of adults and students have reached the national goal of schistosomiasis control in 2008.
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This report overviewed the national endemic status of schistosomiasis in China in 2008. During the whole year of 2008, a total of 412 927 cases of schistosomiasis were estimated and 57 acute cases were reported, among which one acute case infected with Schistosoma mansoni was imported from overseas. The reduction rates of total cases and acute cases were 19.97% and 32.53% when comparing to those in 2007, respectively. A total of 21 222 advanced cases were treated in 2008 with an increase rate of 15.04% comparing with that in 2007. About 372 263. 11 hm~2 of areas infested with Oncomelania snails were found in 2008, and about 1 197. 89 hm~2 newly detected areas were found in non-infested areas with Oncomelania snails, in historical records. There were 1 468 669 head of the cattle with its infection rate of 1.34% in schistosomiasis transmission regions, with reduction rates of 1. 86% and 36.79% , respectively, comparing to those in 2007. However, cattle were still remaining as the main infectious source for the transmission of schistosomiasis. Six provinces including Jiangsu, Anhui, Jiangxi, Hubei, Hunan, and Yunnan reached the national criteria of infection control. Sichuan Province reached the national criteria of transmission control. The country achieved the mid-term goal of schistosomiasis control written in the document ofOutline of mid- and long-term national programme on control and prevention of schistosomiasis (2004 -2015).
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According to the requirement of the national assessment for achieving the infection control criteria, 42 villages (among them,25 villages belonged to the first stratum, and 17 villages belonged to the second stratum) in 14 counties from 5 provinces, including Hunnan, Hubei, Jiangxi, Anhui and Yunnan, were selected as sampling villages for the assessment.The results from the field assessment showed that 154 out of 9 067 people were found infected with Sckistosoma japonicum, with an average infection rate of 1.7% ranged from 0.31 % to 4.10% , and only Yongping Village from Weishan County and Tenglong Village from Eryuan County were not found any case. A total of 46 out of 3 323 head of cattle were infected with S. japonicum, with an average infection rate of 1.38% ranged from 0.26% to 3.79% , and no any infected individual detected in Nanling County. No outbreak occurred in those sampling villages. Therefore, it is indicated that the five sampling provinces have reached the national criteria on infection control of schistosomiasis.
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Objective To survey and understand the endemic situation of schistosomiasis among 80 national surveillance sites in China in 2008, so as to provide the evidence for decision-making of schistosomiasis control. Methods According to the National Surveillance Protocol for Schistosomiasis, the data of schistosomiasis in residents, domestic animals and Oncomelania snails and other relevant factors were collected and analyzed in the 80 national surveillance sites. Results Among the 80 national surveillance sites, the average positive rate of residents with sera examination and the average infection rate of the residents were 9.86% and 0.67% , respectively, and the infection rate of domestic animals was 1.62% , all remarkably decreased compared with the rates of 2007, but the proportion of domestic animals stable breeding was only 6.07% . The areas of infected snail habitats and the new snail habitats were 177.70 hm~2 and 7.64 hm~2, respectively. The mean density of living snails and infection rate of snails were 0.32/0.1 m~2 and 0. 15% , respectively. Conclusions The endemic situation of residents, domestic animals and snails decreased in 2008 compared with those in 2007, and domestic animals are still the main infection sources of schistosomiasis, the management of domestic animals need to be further strengthened, meanwhile the surveillance and control of snails should be focused on.
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Objective To study the compliance of forbidden depasturing livestock on the marshland with Oncomelania snails in schistosomiasis endemic areas. Methods According to 3 levels of human infection rates as > 10% ,5%-10% and <5% , 2 204 residents selected randomly from the schistosomiasis endemic villages were sampled with the stratified cluster sampling method in Hunan, Hubei, Jiangxi, Anhui, Jiangsu, Sichuan and Yunnan provinces, and investigated by questionnaire. The contents of the questionnaire included the recognition and implementation of forbidden depasturing livestock on marshland with Oncomelania snails and breeding livestock in bam. Results A total of 78.4% residents agreed forbidden depasturing livestock on marshland with snails, but 3. 7% residents disagreed it. A total of 83. 9% residents considered the relationship between breeding livestock in bam and schistosomiasis control, but 3. 1% residents thought that it was no relationship. The main reasons of depasturing livestock on marshland with Oncomelania snails were the high cost of breeding livestock in bam (36. 2% ) , unaccustomed (26.4% ) and no room for breeding livestock in bam (25.4% ). Conclusion Forbidden depasturing livestock on the marshland with Oncomelania snails should be strengthened according to the local economic, nature environment, agriculture, residents'culture degree and agriculture habit.
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<p><b>OBJECTIVE</b>To identify Oncomelania hupensis snail habitats and areas with high transmission potential by GIS/RS.</p><p><b>METHODS</b>Marshland areas near high endemic villages of schistosomiasis in the Poyang Lake region were selected. Corresponding map was digitized and (Landsat 5 TM) image was corrected according to the digital map. The image in dry seasons was calculated by both normalized difference vegetation index (NDVI) and tasseled cap model.</p><p><b>RESULTS</b>Result showed that snails spots were distributed in class 6, 7 and 8. Farther analysis of both NDVI and tasseled cap model showed that the snail habitats were mainly distributed in the areas where NDVI value was more than 110, and in tasseled cap wetness value between -10 to 3 with correction rate 94.93%.</p><p><b>CONCLUSION</b>First step was to use unsupervised classification to define the class 6, 7 and 8 snail habitat environment. Second step was to extract the value by NDVI model, and to define a healthy vegetation as snail suspicious habitat when NDVI value was more than 110. Then the third step was to use tasseled cap wetness model to define the areas as snail habitats which value was between -10 to 3.</p>
Subject(s)
Animals , Demography , Disease Vectors , Schistosomiasis , SnailsABSTRACT
[Objectice] To study the relationship between the livestock trade and schistosomiasis transmission and to provide an evidence for making a strategy of schistosomiasis control in mountainous areas. [Methods] A retrospective survey and analysis was conducted to investigate the prevalence of schistosomiasis in both humans and livestock (cattle, horses, mules, donkeys and pigs), and the number and migration of livestock in Weishan County, Yunnan Province in 1980～ 1991. [Results] A positive correlation was found between the infection rate of residents and the numbers of livestock migration (R=0. 9151, P＜0.01). During 1980 to 1991 the infection rate was increased gradually along with the development of livestock husbandry, especially, from the economic reforms since 1984. In 1984 there was positive correlation in the infection rate both human and livestock (R=0. 8458, P＜0.05). The results show that the infection rates of livestock on sale including cattle, horses, mules, donkeys and pigs are 9.54%, 29.39%, 16.38%, 14.47%, 25.73% and 11.11%, respectively. [Conclusion] The infection rate of human and livestock arises by parallel. The high frequency of livestock trade resulted in serious spreading of the infection source of schistosomiasis. The migration of the infected livestock might be an important factor in transmitting schistosomiasis.
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Objective To survey and understand the endemic situation of schistosomiasis in China in 2007,so as to provide the evidence for decision-making of schistosomiasis control.Methods The data of investigation on schistosomiasis in residents,domestic animals,Oncomelania snails and other relative factors were collected and analysed in the 80 national surveillance sites,2007. Results In 2007,the total infection rate of the residents was 0.92%,which decreased by 42.31% compared with that in 2006. There was no site where the resident infection rate was more than 5% among all the 80 surveillance sites. The peak of the resident infection rate with different age groups appeared at the 50-60 age group. The cattle and buffalo were still the main infection targets. The infection rate of domestic animals was remarkable decreased. The density of living snails was 0.430 0/0.1 m2. The percentage of frames with living snails was 0.06%. The density of infected snails was 0.000 7/0.1 m2,and the snail infection rate was 0.16%. All of them were decreased compared with those of 2006. Conclusion The schistosomiasis endemic in the residents,cattle and snails was remarkable decresed in the national surveillance sites,2007.
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Objective To analyze comprehensively the investigation data of the national schistosomiasis surveillance sites from 2005 to 2007, in order to provide the evidence for mastering the endemic situation and pattern of schistosomiasis. Methods Eighty surveillance sites were selected, and the investigation data about schistosomiasis in residents and domestic animals and the status of Oncomelania snails in these sites were collected and analysed. Results From 2005 to 2007, the total infection rate in residents decreased by 54.90% (average decreased by 18.30% each year). The sites where the infection rate in residents was higher than 5% decreased year by year. In 2007, there was no site where the infection rate in residents was higher than 5% in all the 80 surveillance sites. All the infection rates in different age groups decreased for three years in succession, and the peak appeared at 30-50 age group in 2005, but moved to 50-60 age group in 2007. The infection rate in domestic animals decreased by 69.22%, and the infection rate in cattle and buffaloes remarkably decreased. For the three years, the areas with snails reduced by 8.84%, and the areas with infected snails reduced by 53.23%. The average densities of living snails and infected snails decreased year by year, but the infection rate of snails fluctuated during the three years. Conclusion The endemic situation of schistosomiasis in residents and cattle, and the status of snails, in general, remarkably decreased from 2005 to 2007.
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Objective To understand the endemic situation of schistosomiasis among 80 national surveillance sites for schistosomiasis in 2006,so as to provide scientific evidence for making out schistosomiasis prevention and control measures. Methods According to the national surveillance protocol, the endemic situation of schistosomiasis in residents and livestock, and the status of Oncomelania snails and other factors were investigated in the 80 national surveillance sites for schistosomiasis, and all the data were collected and analysed. Results Among the 80 national surveillance sites,the average positive rate of residents with sera examination was 13.60% and the average positive rate with stool examination was 1.59%.The average positive rate of floating population with sera examination was 5.79%. There were 143 advanced patients among the national surveillance sites, and 12 acute patients were reported in 2006, but no breaking-out epidemic reported. The proportion of domestic animals stable breeding were about 4.74% of 5 365 examined animals in 2006, and the others were not.The infection rate of domestic animals was 5.93% that declined by 34.49% compared with that in 2005 and especially for the infection rate of cattle and sheep. A total of 7 429.63 hm2 of areas were surveyed. The areas of snail habitats, infected snail habitats and the new snail habitats were 4 994.01,621.75 hm2 and 21.75 hm2,respectively. The density of living snails and infection rate of snails were 0.544 8/0.1 m2 and 0.37%, which increased compared with infection rate of 0.26% in 2005. Conclusion The endemic situation of residents, cattle and snail habitats declined in 2006 compared with those in 2005 in the national surveillance sites.
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Objective To understand the potential impact of south-north water transfer project on transmission and distribution of Schistosomiasis japonica, and to put forward the countermea-sures of prevention of the disease transferring into other places. Methods The information on the progress of south-north water transfer project and factors related to the distribution of Schistosoma juponicum were collected, and the suggestions on improving the countermeasures were obtained through the group discussions and field visits. Results The potential impact of the project on the disease transferring is existed, mainly the disease transferring will be through the Lixia River basin in Jiangsu Province, and Chaohu areas of Anhui Province in the east route, and Sihu areas of Hubei Province in the middle route. The snail transferring northward will be affected both by the project and global warming, as a result, the endemic areas of Schistosomiasis will probably transfer into the Hongzehu and Chaohu areas in the future. Conclusion In the east route of the project, if the project is not combined with Schistosomiasis control, the endemic areas of Schistosomiasis will extend into other regions, the loss in the society and economy will be very large.
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Oncomelania hupensis is the intermediate host of Schistosoma japonicum, and its distribution is consistent with that of schistosomiasis.Temperature is an essential environmental factor for the survival of snails.Therefore, it is important to study the impact of climate warming on snail-breeding and schistosomiasis transmission.This paper reviews the importance of climate warming to snail breeding and the spreading of the disease, and the application of relative research techniques.
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Possible impact of ecological and social environmental changes due to the construction of the Three Gorges Dam on the transmission of schistosomiasis draws great attention of the health authority and publics. This article reviews the situation and progress of research on schistosomiasis transmission in reservoir area from three aspects: the possibility of snail spreading and breeding, imported infection sources and social behavioral factors of the people.