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A quantitative framework for evaluating the effect of community treatment on the morbidity due to ascariasis

Published online by Cambridge University Press:  06 April 2009

G. F. Medley ,
H. L. Guyatt  and
D. A. P. Bundy
G. F. Medley
Affiliation:
Wellcome Trust Centre for Research into Parasitic Infections, Imperial College of Science, Technology and Medicine, London SW7 2BB
H. L. Guyatt
Affiliation:
Wellcome Trust Centre for Research into Parasitic Infections, Imperial College of Science, Technology and Medicine, London SW7 2BB
D. A. P. Bundy
Affiliation:
Wellcome Trust Centre for Research into Parasitic Infections, Imperial College of Science, Technology and Medicine, London SW7 2BB
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Summary

There is growing emphasis on the use of community treatment to reduce the level of morbidity caused by helminth infection. The design of chemotherapy programmes, in terms of frequency of treatment and proportion of the community treated, would be assisted by a quantitative framework which enabled the morbidity reduction achieved by different approaches to be compared. The present study describes a model developed for this purpose which embodies two innovative features. First, a quantitative score of morbidity (the proportion of individuals harbouring an intense infection) is used to rate the success of a programme and, second, the distribution of helminths in the host population is generated by a mechanism that allows the distribution to change dynamically as a function of both treatment and reinfection. The model behaviour, using values typical of Ascaris lumbricoides, indicates that the benefit derived from community chemo- therapy increases non-linearly with the coverage and efficacy of treatment.

Keywords

geohelminthsepidemiologymass chemotherapyAscaris lumbricoidesmathematical models.
Type
Research Article
Information
Parasitology , Volume 106 , Issue 2 , February 1993 , pp. 211 - 221
Copyright
Copyright © Cambridge University Press 1993

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