Effects of Cd(+2), Cu(+2), Ba(+2) and Co(+2) ions on Entamoeba histolytica cysts

The effects of cobalt, copper, cadmium and barium ions on the cysts of Entamoeba histolytica (E. histolytica), an amebic dysentery agent, cultured in Robinson medium were investigated.

E. histolytica cysts and trophozoites isolated from a patient with amebiasis were cultivated in the medium, incubated at 37 degrees for a period of 4 days and 40 x 10(4)/ml amebic cysts were then transferred to a fresh medium. At the second stage, 0.05, 0.1 and 0.2 mM of selected metal ions were added to the medium, and the effects of these ions on parasitic reproduction compared with the control group were observed.

It was determined that the number of living parasites in all the groups containing metal ions decreased significantly starting from 30 minutes (P<0.01). CuCl2 showed the highest lethal effect on E. histolytica cysts, whereas the lowest lethal effect was observed with CoCl2. It was also seen that the number of living cells was decreased as the ion concentration and exposure time were increased, and that there were no living parasites in the medium at the end of 24 h (P<0.01).

It may be stated that the effect of ever-increasing contamination of the environment with metal waste materials on parasites should be investigated further.