[Current prevalence of Clonorchis sinensis infection in Jiangmen, Guangdong Province].

OBJECTIVE: To investigate the prevalence of clonorchiasis in Jiangmen City. METHODS: From May to December 2011, each town was randomly chosen from east, south, west, north and central area of 7 cities/districts of Jiangmen City. Four or five villages were randomly selected from each town. In each village, the residents above 3-year-old in 10% randomly sampled families were treated as research objects. Total of 14,000 fecal boxes were issued and 12,661 ones back. Eggs in stool were examined by modified Kato-Katz thick smear method (three slides per specimen). RESULTS: A total of 1316 clonorchiasis cases were found from 12,661 pepople in 140 villages with a prevalence of 10.39% (1316/12,661). The average egg density was 98.3 eggs per gram (EPG) feces. Among 7 cities/districts, the prevalence in Pengjiang District (26.68%, 402/1507) was the highest, and that of Taishan City (0.93%, 19/2049) was the lowest. The egg density in Heshan City was the highest (225.4 EPG) and the lowest one was found in Taishan City (5.13 EPG). The prevalence was negatively related with the distance to major rivers (r=-0.61, P<0.01). The prevalence and the egg density in males and females was 13.20% (807/6112) and 80.9 EPG, and 7.77% (509/6549) and 39.4 EPG, respectively. The prevalence and intensity of infection increased obviously in the groups of above 20-year-old. The people with a higher prevalence was the group of 60-69 year-old, and the people above 70 years showed heavier infection (153.8 EPG). Light, moderate and heavy infection occupied 99.91%, 0.09%, and 0. CONCLUSION: Clonorchiasis is endemic in seven districts of Jiangmen City with different epidemic degrees. There are significant differences in the prevalence and intensity of infection among different areas. The villages with higher prevalence distribute along the middle and lower sections of the two major rivers.

[Pilot observation on the effect of integrated control measures against clonorchiasis in Pengjiang District of Jiangmen City].

From June to December in 2008, five villages were randomly chosen from Pengjiang District of Jiangmen city and about five hundred residents from each village were examined for clonorchiasis by Kato-Katz method (three slides per specimen). Fifty residents from each village were re-examined one month after treatment. One year later 50 treated residents were chosen from Dalin village and Sanya village for fecal examination. Questionnairing was conducted to determine the knowledge rate on clonorchiasis prevention among residents. The percentage and usage of sanitary toilets were investigated. The average infection rate of clonorchiasis from five villages was 21.5%(537/2501). 86.6%(465/537) of clonorchiasis received treatment voluntarily. One month after treatment the infection rate in four villages declined significantly. The positive rate showed no significant difference between one month and one year after treatment in Dalin and Sanya villages (P>0.05) . Questionairing indicated that 41.2%(170/413) of the clonorchiasis cases ate raw fish frequently, which was significantly higher than those non-infected people [4.2%, 8/192] (P<0.05). After health education, the knowledge awareness rate raised from 23.1% (135/584) to 84.5% (349/413) (P<0.05). The dissemination and usage of sanitary toilets were 93.2% (38 068/40 848) and 100%, respectively.

[Cloning and expression of the gene encoding rat IgE-dependent histamine-releasing factor and effect study on the recombinant protein].

AIM: To clone and express the gene encoding rat IgE-dependent histamine-releasing factor (rHRF) and to study the effect of recombinant rHRF to induce histamine release from rat sensitized mast cells. METHODS: The complete coding region of rHRF was cloned and expressed in BL21 cells. The soluble recombinant rHRF was purified. Aliquots of the mast cells obtained from the lungs of OVA-immunized rats were separately stimulated by recombinant rHRF at different concentration. The released histamine was measured by the OPT spectrofluorometric procedure. RESULTS: The cloned DNA fragment showed 97% nucleotide sequence identity and 95% deduced amino acid sequence identity with the mRNA of rat IgE-dependent histamine-releasing factor (or translationally controlled tumor protein) in GenBank. The recombinant rHRF showed a relative molecular mass of 24 000 in SDS-PAGE. The purified rHRF which was independent of the allergen induced histamine releasing from the sensitized mast cells in a dose-dependent manner. CONCLUSION: The recombinant rHRF, which showed the effect of inducing histamine release from sensitized mast cells, would play an important role in the allergen diseases.