In vitro study of disinfectants on the embryonation and survival of Toxascaris leonina eggs.

The effect of six available and commercial disinfectants on the embryonation and larval development of Toxascaris leonina eggs was studied. Dettol® and Virkon® both induced a 100% reduction in larval development (P ≤ 0.05). Dettol® resulted in deformed eggshells and a halt in embryonal development at 1 week post exposure. All Virkon®-treated eggs showed an early embryonic lysis 24 h post exposure. TH4+ and 70% ethanol both significantly (P ≤ 0.05) affected larval development, with 58.8 and 85.8% reduction, respectively. Neither sodium hypochlorite nor phenol significantly affected larval development (2.8 and 21.0%, respectively). Sodium hypochlorite treatment caused a visible decortication of the eggshell; however, phenol-treated embryonated Toxascaris eggs appeared more or less morphologically normal. In conclusion, the disinfectants tested induced variable degrees of decortication and suppression of larval development. Virkon®S was the most effective disinfectant against Toxascaris eggs, suggesting that it is the most advisable one to use. To the best of our knowledge, this is the first report of the use of Virkon®S as an ovicide and/or larvicide of helminths, particularly Toxascaris leonina.