Cryopreservation of trichomonas vaginalis: a trial of useing four different cryoprotectants

To reach the maximum survival rate of Trichomonas vaginalis after cryopreservation, four substances; namely, dimethylsulfoxide [DMSO], glycerol, egg yolk and horse serum, were used as cryoprotectants. T. vaginalis trophozoites, in the logarithmic phase, cultured on TYM-S medium were used. Rapid and slow freezing schedules were followed. Examinations for viable organisms were done after a month duration in liquid nitrogen. Immediate and delayed thawing was tried. Viability scores depended on the presence of live organisms in the thawed parasite suspensions determined by the presence of motile trophozoites under microscopic examination, by dye uptake and re-suspension of the organisms in fresh TYM-S and watching for parasite growth and multiplication. Rapid freezing protocol failed to cryopreserve T. vaginalis with any cryoprotectant. DMSO was superior to glycerol, especially in 10% concentration by slow freezing. Viable organisms were more when the suspensions were immediately thawed without delay

Molecular identification of coproantigens of Cryptosporidium parvum compared to conventional staining techniques

To compare the immunologic techniques with the conventional staining methods [mainly modified Ziehl-Neelsen, MZN], 93 children [65 immunocompromised and 28 immunocompetent] potentially at risk of Cryptosporidium parvum were studied. Using MZN, a prevalence of 10.7% in diarrheic children was found. ELISA coproantigen and detection of 23 kDa band of immunoblotting by serum IgG were sensitive and specific. They gave 85.7% sensitivity, 100% specificity, 100% diagnostic accuracy, 100% positive predictive value and 98.9% negative predictive value. ELISA detection of serum IgG gave 85.7% sensitivity, 97.7% specificity, 96.8% diagnostic accuracy, 75% positive predictive value and 98.9% negative predictive value. So, it was concluded that 23 kDa band determined by ELISA is a valuable sensitive and specific mean of diagnosing cryptosporidiosis, as this antigen is a consistent target of the humoral immune response

Compatibility of Biomphalaria alexandrina snails to Infection with Schistosoma mansoni after exposure to sublethal concentations of Myrrh

The effect of exposing B. alexandrina to the sublethal dose [LC10 and LC20] of myrrh, on its susceptibility to infection with S. mansoni miracidia were determined. At three weeks post miracidial exposure, cercarial shedding was monitored. No shedding of cercariae was observed from snails treated with LC20. In snails treated with LC10, longer prepatent cercarial and shorter cercarial production periods than those of the control group were recorded. The number of infected snails and shedding cercariae was decreased. The study revealed that the sublethal values of myrrh decreased the compatibility of B. Alexandrina to S. mansoni infection, thus proved to have an important role in the control of schistosomiasis