IN A PREVIOUS publication1 I reported on the use of a new drug, thiabendazole (Mintezol), in the treatment of pinworm infestations. I showed that when given in a dosage of 25 mg/kg of body weight twice daily for two days a conversion rate of 98% was obtained, as demonstrated by repeated examination for ova from the perianal area using wax-tipped applicators. This compared with an 80% conversion rate when a single dose of pyrvinium pamoate (Povan) was used in a dosage of 50 mg/kg and a 30% spontaneous conversion with a placebo (Table 1).
Since no vermifuge is effective against the unhatched ova, it seemed logical that a single dose or round of therapy could not be as effective as one in which the dosage was repeated at a suitable interval in order to eradicate those worms which had hatched in the interim.
This study was planned to compare