Prevalence and polyparasitism of intestinal protozoa and spatial distribution of Entamoeba histolytica, E. dispar and Giardia intestinalis from pupils in the rural zone of Man in Côte d’Ivoire
Author(s) : Mamadou Ouattara, Kigbafori Dieudonné Silué, Aya Nicaise N’Guéssan, Ahoua Yapi, Matthys Barbara, Giovanna Raso, Juerg Utzinger, Éliezer N’Goran , UFR biosciences université d’Abidjan-Cocody 02 BP819 Abidjan Côte-d’Ivoire, Centre suisse de recherches scientifiques 22 BP 770 Abidjan Côte-d’Ivoire, Swiss Centre for International Health Swiss Tropical Institute Socinstrasse, 57 Postfach CH-4002 Basel Switzerland, Molecular Parasitology Laboratory Queensland Institute of Medical Research Brisbane Queensland 4006 Australia, School of Population Health University of Queensland Herston Road, Brisbane QLD 4006 Australia, Department of Public Health and Epidemiology Swiss Tropical Institute P.O. Box, CH-4002 Basel Switzerland.
Summary : Diseases caused by environmental contamination by micro-organisms, including intestinal helminths and protozoa, are prevalent in developing countries. According to some authors, their strong expansion in some zones of these countries is due primarily to favourable climatic conditions, combined with inadequate hygiene measures and cleaning and the generally low socio-economic level. Progress in disease control has resulted from new studies that improve our understanding of the epidemiology of helminthiases and from the availability of simple tools that are inexpensive and effective against these diseases (chemotherapy with albendazole and mebendazole). On the other hand, surprisingly few such studies have looked at intestinal protozoa, although the WHO reports that approximately 480 million individuals throughout the world are infested by amoebiasis caused by the protozoon Entamoeba histolytica and that 40 000-110 000 people die from it each year. Giardiasis, a cosmopolitan parasitosis, is due to another intestinal protozoon called Giardia intestinalis. To help develop a database on these parasites, we conducted a cross-sectional epidemiological survey in the Man region in western Côte d’Ivoire. Its objectives were to determine the prevalence of intestinal protozoa, to evaluate polyparasitism and to assess the spatial distribution of the pathogenic protozoal species, E. histolytica and G. intestinalis. Overall, 4466 stools samples taken from pupils aged 6 to 16 years of age at 57 different schools were analyzed under an optical microscope by the formol-ether stool concentration method, after preservation in sodium acetate-acetic acid-formalin (SAF). The most common protozoa species in this area were Endolimax nanus (83.8%) and E. coli (74.7%). The regional prevalence of G. intestinalis was 17.5% and of E. histolytica/E. dispar 11.3%. Both species were found in each of the 57 schools. The prevalence of E. histolytica/E. dispar exceeded 15% in six schools, and its spatial distribution was highly disparate. On the other hand, three large areas with substantial G. intestinalis transmission were identified. Polyparasitism of intestinal protozoa is very frequent in these areas\; 80.2% of pupils carried at least 2 species. This work confirms the presence and breadth of protozoa species in the Man region. Understanding the spatial distribution of the principal areas where pathogenic protozoa species are transmitted may help to develop programmes for disease control that combine chemotherapy and preventive measures.
Figure 1 Prévalence d’infestation par âge (A) et par
sexe (B) selon le nombre d’espèces de protozoaires intestinaux par
individu dans 57 villages de la région de Man.
Figure 1 Prevalence of infestation by age (A) and
sex (B) according to the number of species of intestinal protozoa
per pupil in 57 villages of the Man region.
Figure 2 Répartition
d’Entamoeba histolytica/Entamoeba dispar et de
Giardia intestinalis dans 57 localités de la région
montagneuse de Man à l’ouest de la Côte-d’Ivoire.
Figure 2 Distribution of
E. histolytica/E. dispar and G. intestinalis in 57
localities in the mountainous Man region of western Côte
d’Ivoire.NB : la taille des cercles est en fonction du pourcentage
d’individus infestés par ces espèces.
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