My recommendation is retreatment with the following. Metronidazole (500 to 750 mg PO three times daily for 7 to 10 days in adults and 35 to 50 mg/kg per day in three divided doses for 7 to 10 days in children) is the usual treatment for invasive colitis. Patients with invasive colitis should generally be treated with a luminal agent following a nitroimidazole. Paromomycin and diiodohydroxyquin (iodoquinol) are available.
Prevention — Prevention of amoebic infection in travellers involves avoidance of drinking unboiled or unbottled water in endemic areas.
Uncooked food such as fruit and vegetables that may have been washed in local water should also not be consumed. Amoebic cysts are resistant to chlorine at the levels used in water supplies, but disinfection with iodine may be effective. Avoiding sexual practices that may lead to fecal-oral contact is also advisable.