Eleven cases of alveolar echinococcosis (Echinococcus multilocularis infection) with non-resectable lesions but treated with albendazole for 17 to 69 months were followed-up clinically and serologically for 4.5-11.5 years. Based on the clinical outcome and computerized tomography (CT) scanning, they were divided into 4 groups of 2 cured cases, 5 stabilized cases, 3 cases with recurrences, and one treatment failure. Forty-seven sequentially collected sera from the 11 cases were analysed by sequential enzyme-linked immunosorbent assay (ELISA) using Em2plus antigen (Em2plus-ELISA) and Western blotting to detect antibody response against Em18 (Em18-Western blots). The antibody levels in one of the cured and 2 of the stabilized cases fell below the cut-off level in the Em2plus-ELISA 4.5-6 years after effective treatment, whereas all other cases, including 2 of those with recurrences, showed large reductions initially but increased again during the follow-up period. Em18-Western blots of the 2 cured cases and 2 of the stabilized cases became negative. IgG subclasses with responses against Em18 which fell to zero included IgG1 (2), IgG3 (one) and IgG4 (one). All other cases showed no decrease in antibody response against Em18. There were, in general, reasonably reliable correlations between the success or failure of chemotherapy and antibody responses by Em2plus-ELISA and Em18-Western blots. These results suggest that both Em2plus-ELISA and Em18-Western blot are potentially useful in evaluating and predicting the efficacy of chemotherapy.

An immunosuppressed rat model was established by injecting cortisone acetate 25 mg/rat twice a week for 4 weeks and 12.5 mg/rat for another 2 weeks subcutaneously. A development of Pneumocystis carinii pneumonia (PCP) was found at the end of the 6th week in all rats. These rats were injected intramuscularly with artemether at 100 mg/kg once a day for 5 consecutive days. All rats were necropsied at the end of the 8th week. The lung impression smears were stained with Gomori's stain, and Pneumocystis carinii cysts were counted. The ultrastructural changes of trophozoite, precyst and cyst were investigated by transmission electron microscopy on the 7th day after treatment.

The ultrastructure of Cryptosporidium parvum, which parasitized on the surface of the intestine of the immunosuppressed mice, was studied by transmission electron microscopy. The parasite was enveloped by the parasitophorous vacuole developed from the host epithelial cell. An electron dense band was found at the attachment site between the Cryptosporidium and the host cell. At the attachment site, the cytoplasma membrane of Cryptosporidium appeared in the form of many membranous folds, and contacted closely with the plasma membrane of the epithelial cell. Rhoptry-like structure and small electron dense granules were found in the merozoite, but their effects on the development of Cryptosporidium are still unknown (Figs. 1-5).

Monoclonal Antibody-Antigen Spot Test (McAb-AST) was used for detecting circulating antigen in sera from patients with schistosomiasis japonicum. McAb-AST positive rate in 308 schistosomiasis patients before treatment was 75.97%. Among the patients who had moderate or severe infection, the McAb-AST positive rates were 91.18% or 100% respectively. However, the McAb-AST cross-reactive rates in 123 normal donors, 98 clonorchiasis patients, 50 paragonimiasis patients and 56 patients with other parasitic diseases were 0%, 3.06%, 4%, and 1.79% respectively. 1.3 and 6 months after treatment, the McAb-AST negative-converting rates in patients who had negative results of stool hatching were 98.03%, 100% and 100% respectively. Compared with the results of detection of circulating antibodies, negative-conversion of circulating antigen in the patients with negative stool hatching appeared earlier and the negative-converting rate of circulating antigen was much higher. Therefore, McAb-AST had significant value in clinical practice because of its high sensitivity, specificity and good reproducibility.