Long term study on the effect of mollusciciding with niclosamide in streamhabitats on the transmission of schistosomiasis mansoni after community-basedchemotherapy in Makueni District, Kenya

Particle and Fibre Toxicology

Birgitte J Vennervald⁴  Eric Muchiri⁶  Joseph K Mwatha¹  Gachuhi Kimani¹  Mark Booth³  David W Dunne⁷  Anthony E Butterworth²  John H Ouma⁸  Henry Madsen⁴  Henry C Kariuki⁵ 

[1] Present address: School of Medicine, Pharmacy and Health, Durham University,Durham, UK;Maseno University, Kisumu, Kenya & c/o PO Box 57864, Nairobi, Kenya;Department of Pathology, University of Cambridge, Cambridge, UK;Present address: Kenya Methodist University, School of Medicine and HealthSciences, P.O. Box 267, Meru, Kenya;Division of Vector Borne Diseases, Kenya Ministry of Health, Nairobi,Kenya;Kenya Medical Research Institute, Nairobi, Kenya;College of Medicine, University of Malawi, Blantyre, Malawi;DBL Centre for Health Research and Development, Institute of VeterinaryDisease Biology, University of Copenhagen, Copenhagen, Denmark

关键词: Molluscicide;    Biomphalaria pfeifferi;    Re-infection;    Schistosoma mansoni;    Bayluscide;   

Others  :  1227995
DOI  :  10.1186/1756-3305-6-107

 received in 2012-12-15, accepted in 2013-04-12,  发布年份 2013

【 摘 要 】

Background

Schistosoma mansoni infection is a persistent public health problem in many Kenyan communities. Although praziquantel is available, re-infection after chemotherapy treatment is inevitable, especially among children. Chemotherapy followed by intermittent mollusciciding of habitats of Biomphalaria pfeifferi, the intermediate host snail, may have longer term benefits, especially if timed to coincide with natural fluctuations in snail populations.

Methods

In this cohort study, the Kambu River (Intervention area) was molluscicided intermittently for 4 years, after mass chemotherapy with praziquantel in the adjacent community of Darajani in January 1997. The nearby Thange River was selected as a control (Non-intervention area), and its adjacent community of Ulilinzi was treated with praziquantel in December 1996. Snail numbers were recorded monthly at 9–10 sites along each river, while rainfall data were collected monthly, and annual parasitological surveys were undertaken in each village. The mollusciciding protocol was adapted to local conditions, and simplified to improve prospects for widespread application.

Results

After the initial reduction in prevalence attributable to chemotherapy, there was a gradual increase in the prevalence and intensity of infection in the non-intervention area, and significantly lower levels of re-infection amongst inhabitants of the intervention area. Incidence ratio between areas adjusted for age and gender at the first follow-up survey, 5 weeks after treatment in the non-intervention area and 4 months after treatment in the intervention area was not significant (few people turned positive), while during the following 4 annual surveys these ratios were 0.58 (0.39-0.85), 0.33 (0.18-0.60), 0.14 (0.09-0.21) and 0.45 (0.26-0.75), respectively. Snail numbers were consistently low in the intervention area as a result of the mollusciciding. Following termination of the mollusciciding at the end of 2000, snail populations and infections in snails increased again in the intervention area.

Conclusion

The results of this study demonstrate that in the Kenyan setting a combination of chemotherapy followed by intermittent mollusciciding can have longer term benefits than chemotherapy alone.

【 授权许可】

   
2013 Kariuki et al.; licensee BioMed Central Ltd.

【 图 表 】

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