ABSTRACT
OBJECTIVE@#To evaluate the diagnostic efficacy of indirect haemagglutination assay (IHA) for detection of Schistosoma japonicum infections among boatmen and fishermen in Dongting Lake region, so as to provide insights into improving the schistosomiasis surveillance program among boatmen and fishermen.@*METHODS@#The boatmen and fishermen were detected for S. japonicum infections using IHA and Kato-Katz technique or miracidium hatching test nylon gauze simultaneously at schistosomiasis testing sites in the anchor sites for boatmen and fishermen in the Dongting Lake region during the period from 2014 to 2016, and using IHA for serological screening followed by parasitological testing of seropositives during the period from 2017 to 2019. The sensitivity and specificity of IHA were evaluated for detection of S. japonicum infections among boatmen and fishermen, with the 2014-2016 parasitological testing results as a gold standard. In addition, the seroprevalence of S. japonicum infections was compared among boatmen and fishermen with different characteristics and among years.@*RESULTS@#A total of 306 schistosomiasis testing sites were assigned for boatmen and fishermen, and a total of 143 360 person-time boatmen and fishermen were tested for S. japonicum infections in the Dongting Lake region from 2014 to 2019. The sensitivity and specificity of IHA were 69.9%, 97.3% and 96.1% (χ2 = 74.6, P < 0.05), and 70.9%, 74.5% and 71.9% for detection of S. japonicum infections from 2014 to 2016 (χ2 = 29.4, P < 0.05), respectively. The seroprevalence of S. japonicum infections reduced from 30.3% in 2014 to 1.8% in 2019 among boatmen and fishermen, appearing an overall tendency towards a decline (Z = 1 552.4, P < 0.05). In addition, male, individuals at ages of 45 to 60 years, full-time boatmen and fishermen were more likely to be seropositive for S. japonicum infections (all P values < 0.05).@*CONCLUSIONS@#The seroprevalence of S. japonicum infections appeared a tendency towards a decline among boatmen and fishermen in the Dongting Lake region year by year from 2014 to 2019. IHA presented a high efficacy for screening of S. japonicum infections among boatmen and fishermen in the Dongting Lake region.
Subject(s)
Animals , Humans , Male , Middle Aged , China/epidemiology , Hemagglutination , Lakes , Prevalence , Schistosoma japonicum , Schistosomiasis/epidemiology , Schistosomiasis japonica/prevention & control , Seroepidemiologic StudiesABSTRACT
ABSTRACT: This article combines influencing factors of farmers' participation in the Rural Living Environment Renovation Project (RLERP) and conceptualizes a model that depicts the relationships between the demographic characteristics of farmers and their perceptions and behavioral response to RLERP. Using a questionnaire survey to collect empirical data, we found (1) A total of 92% of farmers have fully realized the importance of rural living environment, but most people have adopted a wait-and-see attitude and a lack of motivation to participate. (2) A total of 65% of farmers participate in the collection and classification of domestic waste, 22% of the farmers participate in captivity livestock behavior, and 19% of farmers participate in the response behavior of domestic sewage treatment. (3) A significant positive correlation occurs between income level and farmers' cognition and behavior response. (4) The education standards of the public are not correlated with the farmers' cognition but is significantly correlated with farmers' behavioral response. (5) The cognitive and behavioral response of females to RLERP is significantly higher than that of men. 6) In the process from cognition to the action response, farmers' cognition is positively correlated with action response. On this basis, some measures and suggestions to improve the response of farmers to rural living environment renovation are put forward.
RESUMO: Este artigo combina fatores que influenciam a participação dos agricultores no Projeto de Renovação do Ambiente Rural (RLERP) e conceitua um modelo que descreve as relações entre as características demográficas dos agricultores e suas percepções e resposta comportamental ao RLERP. Usando uma pesquisa por questionário para coletar dados empíricos, encontramos: (1) um total de 92% dos agricultores perceberam plenamente a importância do ambiente de vida rural, mas a maioria das pessoas adotou uma atitude de esperar para ver e uma falta de motivação para participar; (2) um total de 65% dos agricultores participam da coleta e classificação do lixo doméstico, 22% dos agricultores participam do comportamento pecuário em cativeiro e 19% dos agricultores participam do comportamento de resposta ao tratamento de esgoto doméstico; (3) uma correlação positiva significativa ocorre entre o nível de renda, a cognição e a resposta comportamental dos agricultores; (4) os padrões de educação do público não estão correlacionados com a cognição dos agricultores, mas estão significativamente correlacionados com a resposta comportamental dos agricultores; (5) a resposta cognitiva e comportamental das mulheres ao RLERP é significativamente maior do que a dos homens; (6) no processo de cognição para resposta de ação, a cognição dos agricultores está positivamente correlacionada com a resposta de ação. Com base nisso, são apresentadas algumas medidas e sugestões para melhorar a resposta dos agricultores à renovação do ambiente rural.
ABSTRACT
As an ancient parasitic disease, schistosomiasis has been endemic in Dongting Lake areas for more than 2 100 years. In the early 20th century, the first human case of schistosomiasis in China was reported in Dongting Lake areas, which was paid extensive attention. After the founding of the People’s Republic of China, large-scale schistosomiasis control activities were launched promptly in Dongting Lake areas, and great successes have been achieved following the three stages of control efforts, including the snail control-based stage, synchronous chemotherapy for humans and livestock-based control stage and infectious source control-based control stage. In 2015, transmission control of schistosomiasis was achieved in Hunan Province. This paper comprehensively describes the discovery and control of schistosomiasis, analyzes the challenges for the current schistosomiasis control programs and proposes the emphasis for future control activities in Dongting Lake areas, so as to provide insights into the schistosomiasis control program in this area.
ABSTRACT
Hunan Province occupies a particular position in the history of the national schistosomiasis control programme of China. The province is hyperendemic for schistosomiasis, and achieves great successes and many experiences at various stages of the national schistosomiasis control programme of China. Recently, remarkable schistosomiasis control benefits have been achieved in Hunan Province because of the strong political will, increased financial support, intensification of the integrated control strategy and sustainable implementation of the four projects, including management of livestock and humans as sources of Schistosoma japonicum infections, snail control and capability building of schistosomiasis control institutions. In addition, a series of schistosomiasis control models have been created from the schistosomiasis control programme, and the concept of control-research combination and research serving for field control has been achieved, which provides the "Hunan experience" for the natonal schistosomiasis control programme of China. Based on the government-led multisectoralcollaboration principle, further actions are required with scientific control and joint prevention and control, implementation of the integrated strategy with emphases on controlling sources of S. japonicum infections and snails, adequate financial support, improved professional capability building, and innovative medical treatment-prevention combination patterns, so as to achieve the goal of schistosomiasis elimination in Hunan Province as soon as possible.
ABSTRACT
Objective To evaluate the effects of water body environments on the microbial community of Oncomelania hupensis snails in marshlands of the eastern Dongting Lake where natural extinction of O. hupensis snails are found, so as to explore the correlation between the natural extinction of O. hupensis snails and the microbial community in snails. Methods Snails were caged water bodies in the Qianliang Lake marshland (Qianliang Lake regions) where natural extinction of snails was found and in the Junshan Park marshland (Junshan Park regions) in the eastern Dongting Lake for 30 days, and then all snails were collected and identified for survival or death. DNA sequencing of the fungi and bacteria was performed in snails before and after immersion in waters, and the biodiversity and abundance were analyzed. Results The survival rates of O. hupensis snails were 28.0% (70/250) and 64.8% (162/250) in Qianliang Lake regions and Junshan Park regions 30 days after immersion in waters, respectively (χ2 = 81.365, P < 0.01). The number of the fungal community and the biodiversity of the bacterial community were both greater in snails caged in Qianliang Lake regions post-immersion than pre-immersion, and there was a significant difference in the structure of the fungal and bacterial communities. The microbial community with a significant difference included Flavobacteriaceae,which was harmful to O. hupensis snails. Conclusion The water body environment affects the composition of the microbial community in O. hupensis snails in marshlands with natural snail distinction around the eastern Dongting Lake; however, further studies are required to investigate whether the natural distinction of snails is caused by water body environments-induced changes of the microbial spectrum in O. hupensis snails.
ABSTRACT
Objective To investigate the reasons of natural extinction of Oncomelania hupensis snails by comparing the difference of the water chemical properties between the snail-breeding marshland and non-snail marshland in Eastern Dongting Lake areas. Methods Three adjoining marshlands in Eastern Dongting Lake areas were selected, one was a snail-breeding marshland, the second was a non-snail marshland, and the third was a boundary zone between them. During the periods of water-rising season, wet season and water-falling season, the water samples from the bottom of 0.5 m were collected by the systematic random sampling method (200 m × 200 m grid method). In addition, the water samples below the surface of 0.5 m were also collected in the wet season. The physicochemical indexes of the sampling water were detected. Results According to the Surface Water Environmental Quality Standard (GB 3838–2002), the water quality indicators which were less than the detection limit were Cr, Cd, Zn, Hg, Cu, S－ and CN－ during the three sampling seasons. The pollutants which were slightly higher than Grade III but lower than Grade IV (Hg ≤ 1 μg/L, TP ≤ 0.1 mg/L) were Hg and TP. The pollutants below the Grade III included As and F－. The temperature and pH values were within the Grade III. The oxygen consumption indicators covering DO, COD and BOD in the water-rising season and wet season were within the Grade III, while the value of BOD was beyond the scope of Grade III but was between Grade Ⅳ (≤ 6 mg/L) and Grade V (≤ 10 mg/L) in the water-falling season. The differences of the water pollution indexes between the snail-breeding marshland and non-snail marshland were statistically significant, and these indexes included F－, As and pH in the water-rising season (P < 0.05); pH, BOD and Fat the surface layer in the wet season (P < 0.05); F－ at the bottom in the wet season (P < 0.05); TP and F－ in the water-falling season. Moreover, the above-mentioned indexes in the non-snail marshland of Qianliang Lake were higher than those in the snail-breeding marshland of Junshan Park. Thus, F－ was the only index which had statistical differences in every sampling season, and the concentration of F－ at the non-snail marshland was also higher than that at the snail-breeding marshland. In the water-rising season, the pH value at the non-snail marshland exceeded the suitable range for the growth of snails (6.8 to 7.8). Conclusion In the Eastern Dongting Lake area, the high concentration of F－ and pH of water may be responsible for the natural extinction of O. hupensis snails.
ABSTRACT
Objective To investigate the reasons of natural extinction of Oncomelania hupensis snails by comparing the difference of the water chemical properties between the snail-breeding marshland and non-snail marshland in Eastern Dongting Lake areas. Methods Three adjoining marshlands in Eastern Dongting Lake areas were selected, one was a snail-breeding marshland, the second was a non-snail marshland, and the third was a boundary zone between them. During the periods of water-rising season, wet season and water-falling season, the water samples from the bottom of 0.5 m were collected by the systematic random sampling method (200 m × 200 m grid method). In addition, the water samples below the surface of 0.5 m were also collected in the wet season. The physicochemical indexes of the sampling water were detected. Results According to the Surface Water Environmental Quality Standard (GB 3838–2002), the water quality indicators which were less than the detection limit were Cr, Cd, Zn, Hg, Cu, S－ and CN－ during the three sampling seasons. The pollutants which were slightly higher than Grade III but lower than Grade IV (Hg ≤ 1 μg/L, TP ≤ 0.1 mg/L) were Hg and TP. The pollutants below the Grade III included As and F－. The temperature and pH values were within the Grade III. The oxygen consumption indicators covering DO, COD and BOD in the water-rising season and wet season were within the Grade III, while the value of BOD was beyond the scope of Grade III but was between Grade Ⅳ (≤ 6 mg/L) and Grade V (≤ 10 mg/L) in the water-falling season. The differences of the water pollution indexes between the snail-breeding marshland and non-snail marshland were statistically significant, and these indexes included F－, As and pH in the water-rising season (P < 0.05); pH, BOD and Fat the surface layer in the wet season (P < 0.05); F－ at the bottom in the wet season (P < 0.05); TP and F－ in the water-falling season. Moreover, the above-mentioned indexes in the non-snail marshland of Qianliang Lake were higher than those in the snail-breeding marshland of Junshan Park. Thus, F－ was the only index which had statistical differences in every sampling season, and the concentration of F－ at the non-snail marshland was also higher than that at the snail-breeding marshland. In the water-rising season, the pH value at the non-snail marshland exceeded the suitable range for the growth of snails (6.8 to 7.8). Conclusion In the Eastern Dongting Lake area, the high concentration of F－ and pH of water may be responsible for the natural extinction of O. hupensis snails.
ABSTRACT
Objective To explore the dynamic changes of Oncomelania hupensis snail densities in autumn and winter and the relationship between hydrological and meteorological factors and snail growth and decline.Methods From Octobers to De-cembers of 2007 to 2014,a bottomland close to eastern Dongting Lake was selected as the study field.The snails and elevation of the points were surveyed,and the hydrological and meteorological data were collected.The snail densities and death rates of every month were calculated.The meteorological and hydrological data were described,and the relationship between the snail densities and associated factors were fitted by the multiple regression model.Results The snail density was highest in October 2012(41.88 per 0.1 m2)and lowest in November 2008(1.23 per 0.1 m2).The snail mortality was highest in November 2008 (73.72%)and lowest in October 2012(1.09%).The multiple regression model found a linear relationship between hydrological and meteorological factors and snail densities.The correlation coefficient between the prediction of ln(snail density)and its mea-surements by using this model was 0.927(P=0.001).Conclusion The average minimum temperature in January and time of starting flood have an obvious influence on the snail densities in autumn and winter.
ABSTRACT
Objective To explore the spatial-temporal characteristics and changing regularities of Schistosoma japonicum in-fections among human from 2004 to 2011. Methods The township level spatial databases of schistosomiasis in Hunan Province from 2004 to 2011 were established,and the related spatial analysis was performed by SPSS 17.0,ArcGIS 10.1 and SaTScan 7.03. Results The schistosome infection rate among human in Hunan Province sharply decreased from 3.0％in 2004 to 0.8％in 2011. However,the rate among residents in parts of some townships in 2011 was still hovering at a higher level (P90=2.12％),and the higher rate was distributed along the Oncomelania hupensis snail ridden areas outside embankment. The auto-correlation analysis showed that the global Moran's I for schistosome infection rate among human was 0.34 to 0.53 from 2004 to 2011,and was higher than the expected value(Z>8.71,P<0.05). The local G statistics indicated that the positive hotspot high-high clustering areas were mainly near the coast of Dongting Lake from 2004 to 2011,and the number of townships with schistosomiasis endemic in the clustering areas reached 30 to 70. The spatial scan analysis showed that the number of townships in the clustering areas ran up to 145 to 183 from 2004 to 2011. Conclusions The schistosome infection rate among human de-creased significantly in Hunan Province from 2004 to 2011. However,the rate in parts of some townships still remains at a com-paratively high level,and there are positive spatial correlation and spatial agglomerations in the schistosome infection rate among human,suggesting that the prevention and control work on schistosomiasis in these areas should be strengthened in the fu-ture.
ABSTRACT
Objective To investigate the temporal and spatial distribution of Schistosoma infection of population and its risk factors in Eastern Dongting Lake area in 2012 and 2014,so as to provide the reference for formulating effective intervention mea-sures. Methods Junshan District was selected as a study field in Eastern Dongting Lake area. The method of spatial autocorre-lation analysis was applied to analyze the change of spatial distribution of Schistosoma infection in Junshan District in 2012 and 2014. The spatial regression model was fitted to detect the risk factors for human infection. Results The livestock infection rate in 2013 was lower than that in 2011. The average infection rate of schistosome was reduced to 0.55%in 2014. The spatial auto-correlation existed on the distribution of schistosomiasis in Junshan District in both 2012 and 2014 and 4 high incidence villages were identified. The results of the spatial error model showed that the prevalence of human infection was positively correlated with the infection rate of the livestock and the area of the susceptible environment in 2012. The spatial lag model showed that the prevalence of human schistosomiasis was positively correlated with the area of the susceptible environment ,but not with the in-fection rate of livestock. Conclusion The measures involving grazing prohibition and phasing out cattle and sheep are remark-ably effective and should continue on the basis of the current spatial distribution of schistosomiasis in this area.
ABSTRACT
Objective To evaluate the effects of the project of ditching for drain on Oncomelania hupensis snail control and flood prevention security and explore the optimal engineering design plan in Dongting Lake region. Methods A retrospective study was performed on the previous studies about the project of ditching for drain. The reference values of project indices were determined. The outside levee of Nanhu New Distinct of Yueyang City in Dongting Lake region was selected as the study area , and the cross section of marshland perpendicular to the center line of the levee was extracted to research. According to the situa?tions of various water levels,a dynamic simulation was performed on the effect and security of the project of ditching for drain through the software FLAC3D. Results The retrospective study showed that the project would be effective when the relatively subsoil water level decreased by 0.35 m,and the soil water content decreased correspondingly. The dynamic simulation by FLAC3D showed that the minimum safe distances between transverse ditch 1,vertical ditch and levee toe should be 25 m and 13 m respectively. The digging depth of transverse ditch and vertical ditch should be 1.2 m and 1.0 m respectively. If the width of marshland in drought period was less than 500 m,one transverse ditch was efficient. Otherwise,more transverse ditches should be set with the intervals of 300 m. Conclusions The project of ditching for drain is an effective ecological snail elimination method. Optimizing the digging depth of ditches and distances between transverse ditches,vertical ditch and levee toe will en?sure the effects and security of the project.
ABSTRACT
<p><b>OBJECTIVE</b>In March 2012, an H7N7 subtype avian influenza virus (AIV) named A/wild goose/Dongting/PC0360/2012 (H7N7) (DT/PC0360) was recovered from a wild goose in East Dongting Lake. We performed whole-genome sequencing of the isolate, and analyzed the phylogenetic and molecular characterization.</p><p><b>METHODS</b>RNA was extracted from environment samples (including fecal samples from wild bird or domestic ducks, and water samples) for detecting the presence of Influenza A Virus targeting Matrix gene, using realtime RT-PCR assay. The positive samples were performed virus isolation with embryonated eggs. The subtype of the isolates were identified by RT-PCR assay with the H1-H16 and N1-N9 primer set. The whole-genome sequencing of isolates were performed. Phylogenetic and molecular characterizations of the eight genes of the isolates were analyzed.</p><p><b>RESULTS</b>Our results suggested that all the eight gene segments of DT/PC0360 belonged to the Eurasian gene pool, and the HA gene were belonged to distinct sublineage with H7N9 AIV which caused outbreaks in Mainland China in 2013. The hemagglutinin cleavage site of HA of DT/PC0360 showed characterization of low pathogenic avian influenza virus.</p><p><b>CONCLUSION</b>Strengthening the surveillance of AIVs of wild waterfowl and poultry in this region is vital for our knowledge of the ecology and mechanism of transmission to prevent an influenza pandemic.</p>
Subject(s)
Animals , Amino Acid Sequence , China , Embryo, Nonmammalian , Virology , Feces , Virology , Geese , Virology , Genome, Viral , Influenza A Virus, H7N7 Subtype , Genetics , Influenza in Birds , Virology , Lakes , Virology , Molecular Sequence Data , Phylogeny , Poultry Diseases , Virology , RNA, Viral , Genetics , Real-Time Polymerase Chain ReactionABSTRACT
Objective To study the reasons of natural death of Oncomelania hupensis snails by comparing the differences of the indicator days covered with water DCW in snail marshland and non?snail marshland around the build of Three Gorges Dam in Eastern Dongting Lake areas. Methods Two marshlands were selected one was a non?snail marshland Qianliang Lake and another was a snail marshland Junshan Park . The measuring points were set through the mechanical sampling. The snails and elevation of the points were surveyed and the data of the water levels from the hydrological station were collected and then DCWs were calculated. Results From 1995 to 2013 DCWs of the marshland of natural death of snails were all more than that of the snail marshland P<0.01 . In Qianliang Lake marshland the difference between DCW before natural death and DCW from natural death until the dam was not significant P=0.23 while DCWs of the two stages both were more than that after the dam P1=0.045 P2=0.002 . Before the build of the dam DCW of the Qianliang Lake marshland of natural death of snails was more than that after the build of the dam P=0.013 and there was the same situation in Junshan Park marshland P=0.005 . The relationship between snail density and DCW was not significant in Junshan Park marshland rs=0.008 P=0.914 and the reference range of DCW of all the measuring points was 76-251 days. Conclusion In the eastern Dongting Lake district the build of Three Gorges Dam and DCW may be not the direct factors affecting the natural death of snails and the latter may change the distribution of snails.
ABSTRACT
Objective To evaluate the effect of ditching for drain on the control of the breed of Oncomelania hupensis snails in beaches of Dongting Lake. Methods From November,2009 to November,2012,an O. hupensis snail infested beach of the Yueyang jail and an O. hupensis snail infested beach of Junshan District were selected as research fields in the eastern Dongting Lake area,and the former,as the intervention field,was performed with the ditching for drain by excavators and the latter,as the control field,was not. Results Before the project implemented,the average soil moisture contents on the beaches in dry seasons of the two fields were both about 35.56%. After the project implemented,in the intervention field,the average soil mois?ture content was 26.53%which was significantly lower than that(35.56%)in the control field(F=6.53,P0.05),and after the project implemented(in 2012),no adult and young snails were found in the interventional field,but in the control field,the average densities of living snails and young snails were 29.37 snails/0.1 m2 and 213±108.45 snails/0.1 m2 respectively. Conclusion The intervention of ditching for drain can decrease the soil moisture contents quickly and change the ecological condition,therefore,can control the breed of O. hupensis snails in the beaches of Dongting Lake.
ABSTRACT
Objective To understand the distribution of univalvia molluscs in Eastern Dongting lake area where the Oncome-lania hupensis is extinct,so as to explore the causes of extinction and to provide the evidence for formulating schistosomiasis con-trol strategy. Methods The univalvia molluscs of the Qianliang Lake district,Jianxin District and Junshan Park were investigat-ed in August of 2013. All the collected snails were classified and identified. The data were analyzed by using the method of Shapiro-Wilk normality test and non-parametric test. The ecological biodiversity differences from each district were compared by the biodi-versity indexes. Results The univalvia molluscs collected were from 6 species in 3 families in Gastropoda class,namely Oncome-lania hupensis Gredler in Pomatiopsidae family,Parafossarulus striatulus,Alocinma longicornis,Parafossarulus sinensis,Bithynia fuchsisana in Bithyniidae family,and one genus provisionally named Radix in Lymaneidae family. In Junshan Park ,a total of 4 553 snails were collected,among which 1 264 were Oncomelania snails. In Jianxin District,336 univalvia molluscs were collect-ed,and no Oncomelania snails were found. In Qianliang Lake district,there were only 7 Alocinma longicornis snails,2 Parafossa-rulus sinensis snails and 1 Parafossarulus striatulus snail collected. There were significant differences among the distributions of the samples from the three districts(χ2=166.225,P<0.01).The Simpson’s diversity indexes in Qianliang Lake area,Jianxin Dis- trict and Junshan Park were 0.402 8,0.718 6 and 0.678 8,respectively,and the Shannon-Wiener indexes of the 3 areas were 0.721 5,1.431 3 and 1.199 9,respectively. Conclusions With the extinction of Oncomelania snails,the species and quanti-ties of other snails become rare in Qianliang Lake area. Whether their causes are relevant is worth further studying.
ABSTRACT
Dongting Lake area is one of the major marshland schistosomiasis endemic areas in China. In recent years spatial epidemiology is widely used in the research of schistosomiasis which is a new opportunity to break through the current wander-ing situation of schistosomiasis control. In this article both the generalized and Dongting-Lake-specific epidemic indicators of schistosomiasis are reviewed to provide the basis to construct the schistosomiasis Geographic Information System GIS database of Hunan Province.
ABSTRACT
Objective To explore the risk factors of newly emerging advanced schistosomiasis patients in endemic areas.Methods The study areas were selected in two counties of Dongting Lake regions and a 1 :2 match case-control study was designed.Sixty schistosomiasis patients,who newly evolved into advanced schistosomiasis from 2006 to 2007,were selected into the case group,and 120 cases with chronic schistosomiasis into the control group.Questionnaires including potential risk factors of advanced schistosomiasis were designed and the information was collected based on face to face interviews.SPSS 12.0 was used to analyze the simple factors and multi ones (logistic regression) attributable to the development of advanced schistosomiasis.Results The history of hepatitis B (OR = 10.729),models of water contact (OR = 3.919) ,yearly exposure days to the infested water (OR = 5.457) and times of chemotherapy in the nearly 10 years(OR = 1.578) were the risk factors of development of advanced schistosomiasis.The times of examinations with positive schistosome eggs were protective factors.No association was found between yearly income,education degree,times of checking for schistosomiasis,times of examination with sera positive results and the emergence of advanced schistosomiasis.Conclusion The high frequency of exposure to the infested water,repeated infections,incomplete diagnosis and treatment are the risk factors of advanced schistosomiasis.The concurrent infection with hepatitis B is associated with the acceleration of development of advanced schistosomiasis.
ABSTRACT
Objective To study whether Microtus fortis can be infected with schistosome in wild. Methods Two villages (Banghu Village of Yueyang County and Nangang Village of Yuanjiang City) were selected as the study pilots. M. fortis were captured from both outside and inside embankment of the 2 villages. The liver, portal vein and mesentery vein of the captured M. fortis were examined for schistosome eggs, adult worms and schistosomula. Results A total of 1 440 M. fortis were captured, and after examined there were no eggs, adult worms and schistosomula of schistosome found. Conclusion M. fortis can not be infected with schistosome in wild environment.
ABSTRACT
Objective To study the impact of precipitation and water level on acute schistosomiasis for providing reference to control acute schistosomiasis in advance. Methods The historical data on precipitation and water level as well as acute schistosomiasis from 2003 to 2007 in Eastern, Southern and Western Dongting Lake regions were collected and analysed for the correlation between acute schistosomiasis and precipitation and water level in local areas. Results Acute schistosomiasis gradually decreased year by year from 2003 to 2007. Compared with 2003, the number of acute schistosomiasis in 2007 reduced by 95.37%. There was no outbreak of acute schistosomiasis from 2005 to 2007.In the period of peak acute schistosomiasis, the average monthly rainfall reduced from year to year for the successive 5 years. There was a significantly correlation between acute schistosomiasis and monthly average water level. Conclusions The acute schistosomiasis is directly affected by nature factors and has a close correlation with the rainfall and water level in Dongting Lake regions.
ABSTRACT
Objective To understand endemic diversity on schistosomiasis transmission after reserving plain for flooding. Methods In two study pilots, Jicheng and Qingshanhu, epidemiological factors were investigated longitudinally, and the effectiveness of the interventions was evaluated. Results The infection rates of mobile people who engaged in activities in the discarded plain were increased year by year. The density of infected snails was high. The snail habitats increased significantly in Jicheng, but decreased in Qingshanhu. The infection rate and number of livestock pastured in the discarded plain increased. In the discarded plain, most of the mobile people came from the local areas, and main activities for water contact were fishing and pasturing. About 90% of local residents migrated into endemic areas, and the others into non-endemic areas. Conclusions The discarded plains were evolving to a serious transmission zone of schistosomiasis. Interventions combined with agriculture and fisher productions can decrease snail-spreading. Schistosomiasis examination and chemotherapy for the migrants to non-endemic areas are vital.