Micro-geographical variation in exposure to Schistosoma mansoni and malaria, and exacerbation of splenomegaly in Kenyan school-aged children

BMC Infectious Diseases

David W Dunne⁸  Eric Muchiri²  John H Ouma⁴  Amos Otedo⁶  Joseph K Mwatha⁶  Gachuhi Kimani⁶  Clifford Amaganga⁵  Edmund Ireri⁶  Hilda Kadzo¹  Henry C Kariuki²  Anthony E Butterworth⁷  LeeCarol Kenty⁸  Birgitte J Vennervald³  Mark Booth⁸ 

[1] Kenyatta National Hospital, Nairobi, Kenya;Division of Vector Borne Diseases, Ministry of Health, P.O Box 54840, Nairobi, Kenya;Danish Bilharziasis Laboratory, Jægersborg Alle 1D, 2920 Charlottenlund, Denmark;Maseno University, Maseno, Kenya;Kakamega Provincial Hospital, P.O. Box 560, Kakamega, Kenya;Kenya Medical Research Institute, Nairobi, Kenya;Biomedical Research and Training Institute, P.O. Box CY 1753, Causeway, Harare, Zimbabwe;Division of Microbiology and Parasitology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK

关键词: GIS;    children;    Kenya;    splenomegaly;    malaria;    S. mansoni;   

Others  :  1177095
DOI  :  10.1186/1471-2334-4-13

 received in 2003-11-17, accepted in 2004-05-17,  发布年份 2004

【 摘 要 】

Background

Schistosoma mansoni and Plasmodium falciparum are common infections of school aged children in Kenya. They both cause enlargement of the spleen, but their relative contribution to the condition of splenomegaly remains unknown in areas where both infections are endemic. Here, we have investigated whether relatively high exposure to both infections has a clinically measurable effect on this condition.

Methods

96 children aged 6–16 years living along a ten kilometre stretch and within 4 km south of a river that is a source of both S. mansoni and malaria infections were examined clinically for splenomegaly along the mid clavicular line (MCL) and mid axillary line (MAL). The survey was conducted outside the malaria transmission season. The consistency of the organ was recorded as soft, firm or hard. Mapping of the locations of houses and the course of the river was undertaken. Egg counts were mapped at the household level, as were IgG3 responses to Plasmodium falciparum schizont antigen (anti-Pfs IgG3), in order to identify areas with relatively high exposure to both infections, either infection or neither infection. ANOVA was used to test for differences in egg counts, IgG3 levels and the magnitude of spleen enlargement between these areas.

Results

4 contiguous sectors were identified, one where anti-Pfs IgG3 responses and S. mansoni egg counts were both high, one where only anti-Pfs IgG3 responses were high, one where only egg counts were high, and one where both anti-Pfs IgG3 responses and egg counts were low. Spleen MAL and MCL values were significantly higher amongst children from the sector with highest IgG3 levels and highest egg counts but similar amongst children from elsewhere. Both egg counts and anti-Pfs IgG3 responses were significantly higher in children with MAL values >=4 cm. Hardening of spleens was associated with proximity of domicile to the river.

Conclusions

Micro-geographical variation in exposure to S. mansoni and malaria infections can be exploited to investigate the chronic impact of these two infections. These results provide firm evidence that relatively high exposure to both infections exacerbates splenomegaly even outside the malaria transmission season. Major implications include assessing the burden of infection in school age-children.

【 授权许可】

   
2004 Booth et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.

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