Objective To evaluate the effect of DDIA on detecting cattle schistosomiasis. Methods The sera of schistosomiasis cattle, negative control cattle and fascioliasis cattle were detected with DDIA and compared with COPT. Results The sensitivity, specificity and across reaction of DDIA using 10 ?l of sample sera were 95.7%, 96.0% and 20.0% respectively and COPT were 72.9%, 100.0% and 0 respectively. Conclusions DDIA has high sensitivity and specificity for detecting cattle schistosomiasis with 10 ?l of sample serum, and the sensitivity is higher than that of COPT.

In order to explore the available sero-diagnotic method for surveillance in basically controlled and controlled areas of schistosomiasis japonica, a 3 years longitudinal investigation of children 6~14 years old with COPT in 5 endemic areas was carried out after being basically controlled for 8~16 years. The results showed that the examination of children with COPT is one of the available serodiagnostic methods of schistosomiasis for surveillance. In all five areas the positive rate of children in this age group was less than 3%, and the circumoval precipitin rate among the positive cases was less than 5%. Therefore, it is indicated that the above mentioned two indexes can be used for sero-surveillance of schistosomiasis japonica.

A kind of colloidal blue dye(D-l)used as a staining reagent for immunoassay was first selected from the dyes produced in China in this study. The optimun condition for labelling the dye onto sheep antihuman IgG antibody was explored. The dye-labelled antibody could react and stain with relative antigens. The minimal concentration of human IgG protein could be detected with the labelled dye by Dot Double Antibody Sandwich Assay was 20-10ng/ ml. 61 of 62 sera samples of schistosomiasis japonica were positive,the positive rate was 98.4%. Just 1 out of 30 healthy people's sera sambles was positive,the false positive rate was 3.3%. All of 40 Fasciolopsiasis sera samples were negative. The results were similar to that of Dot-ELISA. The activity of antibody labelled with colloidal dye could be maintained for 1 week in room temperature and be presered in lyophilized condition for a longer period. The assay was less expensive,simple to conduct and required no special equipment. It suggested that the Dot Colloidal Dye Immunoassay(DIA)might have potential value for use in schisto-somiasis endemic areas.

Objective To construct and evaluate a novel PAMAM dendrimer vector-DNA vaccine for schistosomiasis japonica.Methods Lysine was used to modify 4.0G PAMAM.and the modified product PAMAM-Lys was synthesized.Agarose gel electrophoresis was used to confirm the composite ratio of plasmid DNA and dendrimer.Micrestructure of the compound was observed by using transmission electronic microscopy,and the stability was analyzed by using electrophoresis.The viability of the cells transfected with dendrimers was evaluated by using a MTT technique in vitro.Fiftyty mice were immunized with purified plasmid pJW4303,pJW4303-Sj23 dendrimer PAMAM-Lys and compound PAMAM-Lys/pJW4303-Sj23,respectively.The specific antibodies of the mice in each group were detected to access the immunoreactivity.Results The agarese gel electrophoresis showed that when the charge ratio of the dendrimer vector and DNA was between 2 and 4,the positive and negative charges could be counteraeted completely,and the compound was blocked completely by DNA electrophoresis.The obscrvation results with transmission electronic microscopy showed that the composition of dendrimer vector and DNA caused shrink of DNA structure.Dendrimer-DNA compound had a good stability.MTT showed the modified dendrimer vector and DNA compound system produced a lower cell toxicity on 293T cell than the unmodified Ones.Thk levels of specific antibodies of the mice immunized with PAMAM-Lys/pJW4303Sj23 were significantly higher than those of the mice immunized with naked DNA vaccine(P<0.05).Conclusions The lysinemodified PAMAM-lys is an excellent vector,and has an appropriate biocompatibility.Lysine-modification can reduce the cell toxicity of PAMAM dendrimer significantly.PAMAM-Lys can enhance the immunoreactivity of DNA vacmine which merits further application in schistosomiasis DNA vaccine.

Objectives To express the miracidial antigen from eggs of Schistosoma japonicum (Chinese mainland strain) (SjMP10), and investigate the role of the miracidial antigen during the hepatic granuloma formation of schistosomiasis. Methods A pair of specific primers was designed and synthesized according to the nucleotide sequence of the open reading frame of the miracidial antigen gene. The open reading frame of the miracidial antigen gene was amplified, digested by restrictive enzyme(BamHI, SalI), and cloned directly into the expression plasmid pGEX-4T-3 to construct the recombinant plasmid. The recombinant plasmids were transformed into E. coli BL21(DE3), and induced by IPTG to express the fusion protein of GST-SjMP10. The expressed fusion protein was purified by electric elution method, and its antigenicity was examined by Western blotting and lymphocyte proliferation test. Results The gene of miracidial antigen was cloned into the expression plasmid pGEX-4T-3. After induced by IPTG, the recombinant expressed a fusion protein of GST-SjMP10, with a molecular weight of 39 000 approximately. The purified fusion protein showed proper antigenicity that could be recognized by the sera of rabbits heavily infected by Schistosoma japonicum and could stimulate the proliferation of splenic lymphocytes of infected BALB/c mice. Conclusion The miracidial antigen from eggs of Schistosoma japonicum was expressed successfully.

Objective To prepare a novel nano-suspension of niclosamide ethanolamine and evaluate its molluscicidal effect. Methods Niclosamide ethanolamine and stabilizing agent—polyvinylpyrrolidone (PVP) were dissolved in dimethyl sulfoxide. After the solution was added into water under fast stirring, niclosamide ethanolamine was quickly precipitated to form nanoparticles and nano-suspension was obtained. The weight ratio of PVP to niclosamide ethanolamine, concentration, temperature, stirring speed on the size and distribution of the nanoparticles were investigated. The molluscicidal effect of niclosamide ethanolamine nano-suspension was measured by immersion and spray methods in the laboratory and field. Results When the weight ratio of PVP to niclosamide ethanolamine was from 1∶2 to 1∶3, the nanoparticles of the niclosamide ethanolamine had diameters about 100 nm and the nano-suspension was stable without agglomerating for more than 1 month; as the speed of the stirring increased, the nanoparticles prepared became smaller and more stable. LC50 of the nano-suspension was 0.0544 mg/L but the LC50 of wettable powder of niclosamide ethanolamine salt (WPN) was 0.1250 mg/L. In the field immersion and spray tests, the concentration of nano-suspension as only 1/5 of active content of WPN achieved the same molluscicidal effect with WPN. Conclusions The nano-suspension has higher molluscicidal effect than WPN and the novel formulation of niclosamide has more advantages than WPN, it is useful for snail control in the field.

Objective To evaluate the toxicity of suspension concentrate of niclosamide(SCN)for molluscicide in the field.Methods According to the state standard of the People's Republic of China "The methods of toxicity test for agriculture register",GB15670-1995,the experiments of acute toxicity on rats and fish were carried out.Results LD50(s)of SCN via mouth and skin with rats were more than 5 000 mg/kg respectively,and LC50(s)of SCN via inbreathe with rats were more than 5 000 mg/m3.Based on the classification of appraising criterion on acute toxicity test,it belonged to a feebleness toxicity degree.The eye and the skin stimulating tests with rabbits showed that it did not irritate the eyes and the skin.For fish,its acute toxicity was slightly lower than that of pure niclosamide,and markedly lower than that of pure niclosamide ethanolamine salt and WPN.Conclusions SCN belongs to a feebleness toxicity degree and has a lower toxicity to fish.It should be a useful molluscicide in endemic areas of schistosomiasis.

This study reported the primary application of FA-ELISA from 107-121kDa fration antibody of Schistosoma Japonicum for detection of the short-term antibody in patients with schistosomiasis. The result showed that this method provided high sensitivity (with positive rate of 93. 33% with 30 cases of schistosomiasis) and good specificity (no false postive in 60 health objects). When one group of schistosome patients were examined with FA -ELISA and with the routine SEA-ELISA before chemotherapy and at 8 months,1 year and 1. 5 year after treatment,it showed good property for evaluation of chemotherapy efficacy with FA -ELISA,which was much better than the routine method.

Objective To screen the bacteria and its components which are toxic to Oncomelania hupensis. Methods The samples of Oncomelania hupensis on the point of death and the soil around the snails were collected. The bacteria existing in the snails and soil were isolated and identified by using regular methods. After being fermented, the toxicity of the bacterium components including the ferment supernatant, split products and bacteria to the snail were tested by the toxicity test. Results Totally, 104 strains of bacteria were isolated from the snails and soil samples, which included Gram positive cocci or bacilli, Gram negative cocci or bacilli. The fermenting supernatant, splitting products and 10 strains of bacteria showed different level of toxicity against the snail respectively. All the fermenting supernatant of bacterium PY1-1, PY7-2, PY3-5, PY19-3, PY2-2-2, PY8-2-2, PY16-1 could kill more than 50 percent of snails. Conclusion The bacteria which are poisonous to snails have been isolated that make a good basis for identifying single toxic component against snails.

Objective To evaluate the molluscicidal effect of colistin E on Oncomelania hupensis. Methods The molluscicidal effect of colistin E on O. hupensis was checked by using the immersion method and spraying method. The toxicity of colistin E on fish was observed by using the toxic test. Results The snail mortality of each group was 100% when the snails were immersed in the colistin E solutions at a concentration of 5. 0, 1. 0 g/L for 24, 48 h and 72 h separately. When the snails were immersed in the colistin E solution at a concentration of 0. 5 g/L for 24, 48 h and 72 h, the death rates were 95% , 100% and 100% respectively; when the snails were immersed in the colistin E solution at a concentration of 0. 1 g/L for 24, 48 h and 72 h, the mortality was 90%, 95% and 100% respectively; when the snails were immersed in the colistin E solution at a concentration of 0. 01 g/L for 24, 48 h and 72 h, the mortality was 70%, 86% and 100% respectively. The snail mortality by the spraying method in a dose of 35, 70, 140 mg/m2 of colistin E was 60%, 100% and 100%. The result of toxic test showed that the toxicity of colistin E on fish was low. Conclusion Colistin E is an effective molluscicide, and is worthy of investigation further.