Rapid reinfection by Giardia lamblia after treatment in a hyperendemic area: the case against treatment.

We selected 40S children aged 1-10 years with Giardia lamblia infection but without abdominal orgastrointestinal complaints for the previous month. For 5 days, 204 received metronidazole 15 mg/kg/day and 201 received B-complex syrup. Stool samples were examined 2-3 weeks and 3 months after treatment and results were tested with chi-squared. Weight and height 6 months after treatment were compared with primary weight and height by Z-score and Student t-test. Metronidazole efficacy at 2-3 weeks was 85.3%. Three months after treatment, 60 were reinfected (34.5%) and 71 had spontaneously cleared (35.3%). Because of high reinfection, spontaneous clearing and treatment failure rates, and the lack of effect on nutritional status or growth, we do not recommend treatment for children with asymptomatic giardia infection.