ABSTRACT
Objective To understand the current prevalence of clonorchiasis in Jiangxi Province. Methods A survey was performed according to the scheme of the 3rd Principal Human Parasites of Jiangxi Province. Based on the ecological regions,a stratified cluster sampling method was applied by the economic and geographic situation. In rural areas,the investigation of C. si?nensis was carried out together with the soil?transmitted helminths investigation,and in the urban areas,the random cluster sam?pling method was applied for the C. sinensis investigation. There were 92 survey sites from 32 counties. The eggs of C. sinensis in stool were examined by Kato?Katz technique,and health knowledge was also investigated by questionnaires in some people at the same time. Results A total of 23 606 sample residents were investigated,and 138 were found infected with C. sinensis, with the infection rate of 0.58%. Light infection was found in most of them. Totally 124 C. sinensis infected persons focused in Xinfeng County,and only a few of infected people scattered in the other counties. In Xinfeng County,851 residents were investi?gated. Among them,the infected people were found in all the age groups except the 0?year age group. The highest infection rate appeared in the 70? years group(24.00%). The male infection rate was 20.29%,which was higher than that of the female (6.25%),showing a statistically significant difference(P<0.01). The infection rate was highest in the population who received high school or technical secondary school education(31.48%). For the occupation distribution,the infection rate was highest in public officers(39.39%). The questionnaire survey showed that the infection rate in the populations in Xinfeng County who had the history of eating raw fish or raw shrimp was 33.15%. Conclusions The distribution of C. sinensis infection presents a region?al aggregation in Xinfeng County,but in other areas,the distribution is sporadic. It is necessary to continue to carry out the para?sitic disease screening,and in Xinfeng County,it is necessary to strengthen the comprehensive prevention and control interven?tion.
ABSTRACT
Objective To explore the impact and change regularity of Oncomelania hupensis snails and vegetation in the marshlands of Poyang Lake caused by the impoundment of the Three Gorges Project. Methods By using the methods of stratified systematic sampling and pinpoint navigation,the succession of vegetation was observed and the distribution of O. hupensis snails was investigated in a period of 8 years on 4 typical marshlands in Poyang Lake. The regularity of changes in vegetation and O. hu-pensis snails was analyzed on the marshlands at high,medium and low elevations,respectively. Results After the impoundment of Three Gorges Project,the average flooding days of these 4 marshlands in 2004 and in 2008 were reduced of 74.8 and 65.8 days compared with those in 2002,the year just before the impoundment of the project,respectively. The change of spatial distribution pattern and the succession of dominant species of vegetation on the marshlands of Poyang Lake have taken place since 2005,and several vegetations showed a trend of moving toward the center of the lake. The hygrophilous vegetation has degenerated and gradu-ally been replaced by mesophily meadow in the marshland area above 14 m elevation. Carex,Phalaris arundinacea and Polygo-num appeared in large area and expanded slowly towards the center of the lake on the marshland below 14 m elevation. O. hupensis snails were mostly found under the Carex association. The tendency of decreasing in density of snails and of migration of snail habi-tats towards low terrain was observed. Conclusions The impoundment of Three Gorges Project has had a significant impact on hy-drological regimes,and a new succession of vegetation has taken place in the marshlands of Poyang Lake. O. hupensis snails and the mesophily vegetation show a trend of migrating slowly to the areas of low elevation in the marshlands.