Open Access Highly Accessed Open Badges Research

Prevalence of intestinal protozoa infection among school-aged children on Pemba Island, Tanzania, and effect of single-dose albendazole, nitazoxanide and albendazole-nitazoxanide

Benjamin Speich12, Hanspeter Marti23, Shaali M Ame4, Said M Ali4, Isaac I Bogoch5, Jürg Utzinger26, Marco Albonico7 and Jennifer Keiser12*

Author Affiliations

1 Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland

2 University of Basel, P.O. Box, CH-4003, Basel, Switzerland

3 Department of Medical and Diagnostic Services, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland

4 Public Health Laboratory (Pemba)-Ivo de Carneri, P.O. Box, TZ-122, Wawi, Chake Chake, Tanzania

5 Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada

6 Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland

7 Ivo de Carneri Foundation, P.O. Box, IT-10122, Milan, Italy

For all author emails, please log on.

Parasites & Vectors 2013, 6:3  doi:10.1186/1756-3305-6-3

Published: 4 January 2013



Pathogenic intestinal protozoa infections are common in school-aged children in the developing world and they are frequently associated with malabsorption syndromes and gastrointestinal morbidity. Since diagnosis of these parasites is difficult, prevalence data on intestinal protozoa is scarce.


We collected two stool samples from school-aged children on Pemba Island, Tanzania, as part of a randomized controlled trial before and 3 weeks after treatment with (i) single-dose albendazole (400 mg); (ii) single-dose nitazoxanide (1,000 mg); (iii) nitazoxanide-albendazole combination (1,000 mg–400 mg), with each drug given separately on two consecutive days; and (iv) placebo. Formalin-fixed stool samples were examined for the presence of intestinal protozoa using an ether-concentration method to determine the prevalence and estimate cure rates (CRs).


Almost half (48.7%) of the children were diagnosed with at least one of the (potentially) pathogenic protozoa Giardia intestinalis, Entamoeba histolytica/E. dispar and Blastocystis hominis. Observed CRs were high for all treatment arms, including placebo. Nitazoxanide showed a significant effect compared to placebo against the non-pathogenic protozoon Entamoeba coli.


Intestinal protozoa infections might be of substantial health relevance even in settings where they are not considered as a health problem. Examination of a single stool sample with the ether-concentration method lacks sensitivity for the diagnosis of intestinal protozoa, and hence, care is indicated when interpreting prevalence estimates and treatment effects.

Intestinal protozoa; Blastocystis hominis; Entamoeba histolytica/E. dispar; Giardia intestinalis; Albendazole; Nitazoxanide; Ether-concentration method