The effects of temperature, light and water upon the hatching of the ova of Schistosoma japonicum.

Eggs of Schistosoma japonicum were obtained from infected patients' feces from Yujiang City, China to observe the effects of temperature, light and water on the hatching of eggs. The temperature of water and light played important roles on the hatching of S. japonicum, but the type of water did not. A constant temperature of 28 degrees C and electrical light produced the highest rate of hatching, and reproducible results, whereas a temperature of 4 degrees C or 37 degrees C, and the absence of light inhabited the hatching of eggs. The percentage of eggs hatched during the first 8 hours of 24 hours incubation was 94.90%, so that using the hatching rate of the first 8 hours could approximate the total hatching rate of samples.

Combinations of three immunological assays for detecting anti-Toxoplasma IgG in the sera of patients infected with Toxoplasma gondii.

Enzyme-linked immunosorbent assay (ELISA), Dot-ELISA and Dot-immunogold silver staining (Dot-IGSS) were simultaneously used to detect the specific IgG against Toxoplasma gondii in 65 patients infected with the protozoa. The positive rates were 86.51%, 92.51% and 98.64%, respectively. When ELISA and Dot-ELISA results were put together, the positive rate increased to 95.38%. When Dot-IGSS results were combined with those of ELISA or Dot-ELISA, the positive rate was raised to 100%. The difference in positive rate between ELISA and Dot-IGSS was significant (x2 = 6.93, p < 0.01), but no statistically significant differences were found between ELISA and Dot-ELISA or between Dot-ELISA and Dot-IGSS. Paired comparison of the reacting intensities of the sera in the 3 assays showed the correlations were highly significant (p < 0.001), with r = 0.608 between Dot-IGSS and Dot-ELISA, r = 0.8194 between Dot-IGSS and ELISA and r = 0.517 between Dot-ELISA and ELISA. Hence combination of different serological assays may increase their sensitivity and specificity for detecting the anti-Toxoplasma antibodies.

Comparative study of Dot-immunogold silver staining and Dot-ELISA for the detection of serum antibodies against Wuchereria bancrofti.

Dot-immunogold silver staining (Dot-IGSS) and Dot-ELISA, using the soluble antigen of Brugia malayi, were employed to detect anti-Wuchereria bancrofti antibodies in 50 cases of Wuchereria bancrofti microfilaremia. The positive rates were 100% and 90% in Dot-IGSS and Dot-ELISA respectively. The average titer in the 45 positive cases was 1:184 (1:10-1:2560) for Dot-IGSS and 1:150 (1:10-1:2560) for Dot-ELISA, with 30 cases showing the same titer in both tests, 13 cases showing higher titer in Dot-IGSS than in Dot-ELISA and 2 cases in the former showing lower titers than in the latter. There was a linear relationship between the titers of antibodies detected by Dot-IGSS and by Dot-ELISA (r = 0.8443). Dot-IGSS, similar to Dot-ELISA, is easy to carry out and the result is easy to read. It is seen that Dot-IGSS is highly sensitive and specific and is practicable for immunodiagnosis and surveillance of filariasis.

The use of dot-immunogold-silver staining (dot-IGSS), dot-ELISA and dot-IGSS to detect serum antibodies from clonorchiasis patients: a comparative study.

We report the use of immunogold-silver staining (IGSS), dot-ELISA and dot-IGSS methods in the study of clonorchiasis in China. These methods were employed to detect the antibody in sera from 40 clonorchiasis patients. The positive rates were 100%, 90.0% and 95.0%, respectively. When the three methods were used to examine 40 normal sera, the negative rates were 100%, 97.5% and 97.5%, respectively. These results suggest that IGSS, dot-ELISA and dot-IGSS are highly specific and sensitive in detecting anti-Clonorchis antibody in patients.