Schistosomiasis in the Republic of São Tomé and Principe: human studies

Abstract

The only schistosome species found in stool specimens in the local population of the republic of São Tomé is Schistosoma intercalatum. An initial survey of schoolchildren showed an overall prevalence of 10.9%, with some schools reaching 29%. No S. haematobium egg was found in 782 urine specimens from the local population, although some were seen in the urine of Angolan soldiers stationed near the capital city. One village in the endemic area, San Marçal, had an S. intercalatum prevalence of 43%, with 14 persons > 40 years of age harbouring severe infections. The transmission area is restricted to the north-east of the main island, where 5 foci apparently account for most of the infections. Seven cases recorded from Principe may be explained by the fact that the children were attending school at São Tomé. Women carrying out domestic activities are more at risk of contracting the infection because of longer periods of water contact than men. The morbidity produced by the infection is restricted to splenomegaly and blood in the stools. High prevalences have been found of Ascaris lumbricoides and Trichuris trichiura, and hookworm and Stronglyloides stercoralis were also observed. Praziquantel was well tolerated and appears to be a good tool for control purposes, although reinfection in the transmission area apparently occurs rapidly. Control strategies based on chemotherapy should take into account an older age group as well as the schoolchildren. Focal mollusciciding and the introduction of washing facilities may also have a role to play in control. The possible recent introduction of the infection to the island is discussed.

Prevalence of intestinal parasitic infections among school children in capital areas of the Democratic Republic of São Tomé and Príncipe, West Africa

“…However, IPIs studies in SAC are quite rare; only two studies conducted in 1987 and 2005 indicated that the prevalence of A. lumbricoides, T. trichiura, and some intestinal protozoan infections were fairly high in SAC [13][14][15][16][17] . Largely from 2005 onwards, the DRSTP accepted the advice of non-governmental organizations (NGOs) to begin SAC-based deworming program using a single-dose mebendazole regimen annually.…”

“…Although limited information is available regarding the IPIs status among inhabitants of the Democratic Republic of Sao Tome and Principe (DRSTP) [13][14][15][16][17] , like other developing countries, IPIs are supposedly a major health problem in the DRSTP due to tropical climatic and poor hygienic conditions. However, IPIs studies in SAC are quite rare; only two studies conducted in 1987 and 2005 indicated that the prevalence of A. lumbricoides, T. trichiura, and some intestinal protozoan infections were fairly high in SAC [13][14][15][16][17] .…”

Permissiveness of two African wild rodents, Mastomys huberti and Arvicanthis niloticus, to Schistosoma intercalatum : epidemiological consequences

“…In our study, M. huberti and A. niloticus released several thousands of S. intercalatum eggs per gram of Kuntz et al (1978) reported a maximal egg output of 1,310/g feces. A recent study has shown that a patient may release an average of 194 S. intercalatum eggs/g feces (Almeda et al 1994). We may thus consider that M. huberti and A. niloticus allow a high production of eggs.…”

“…Until the 1970s this disease had been established in the forest areas of Central and West Africa (Cameroon, Gabon, Zaire). For a decade, S. intercalatum has extended its distribution toward new countries: Equatorial Guinea (Corachan et al 1987), Mali (Corachan et al 1992), Nigeria (Arene et al 1989), and SaÄ o Tome (Almeda et al 1994). However, in spite of the emergence of these new foci the distribution of S. intercalatum remains restricted as compared with that of the intermediate host.…”

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“…Schistosomiasis is endemic on São Tomé but absent in Príncipe [28]. Is it too much to hope that this could sometime be said for malaria on the island?…”