[The development of Ascaris suum eggs in the presence of moxidectin].

The development of Ascaris suum eggs maintained in the culture containing moxidectin (Cydectin, Cyanamid) in concentration 1, 5, 25, and 50 micrograms/ml was studied. The abnormalities and slowing down of the rate of eggs development, depending on the drug concentration, were observed. Exposure of eggs to moxidectin in concentration 1 and 5 microgram/ml resulted in one- or two-week delay of development. In the higher concentration of moxidectin (25 micrograms/ml) only 18% of eggs became invasive. In the presence of 50 micrograms/ml of the drug only few eggs developed to invasive stage after 7 weeks. The development of embryons was stopped more often in the blastula or gastrula stage. The drug's solvent in the highest concentration restricted the development of Ascaris eggs by about 10%. Unembryonated eggs of the worm appeared to be unaffected by 50 micrograms/ml of moxidectin treatment lasting 1-4 days, but for slowing down a little the development rate. The same concentration of the drug in the culture during the first four days of development resulted in 20% reduction of invasive stage in comparison to the control.