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The epidemiology of canine leishmaniasis: transmission rates estimated from a cohort study in Amazonian Brazil

Quinnell, R.J., Courtenay, O., Garcez, L.M. and Dye, C. (1997) The epidemiology of canine leishmaniasis: transmission rates estimated from a cohort study in Amazonian Brazil. Parasitology, 115 (02). pp. 143-156. ISSN 1469-8161

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Abstract

We estimate the incidence rate, serological conversion rate and basic case reproduction number (R0) of Leishmania infantum from a cohort study of 126 domestic dogs exposed to natural infection rates over 2 years on Marajó Island, Pará State, Brazil. The analysis includes new methods for (1) determining the number of seropositives in cross-sectional serological data, (2) identifying seroconversions in longitudinal studies, based on both the number of antibody units and their rate of change through time, (3) estimating incidence and serological pre-patent periods and (4) calculating R0 for a potentially fatal, vector-borne disease under seasonal transmission. Longitudinal and cross-sectional serological (ELISA) analyses gave similar estimates of the proportion of dogs positive. However, longitudinal analysis allowed the calculation of pre-patent periods, and hence the more accurate estimation of incidence: an infection–conversion model fitted by maximum likelihood to serological data yielded seasonally varying per capita incidence rates with a mean of 8·66×10[minus sign]3/day (mean time to infection 115 days, 95% C.L. 107–126 days), and a median pre-patent period of 94 (95% C.L. 82–111) days. These results were used in conjunction with theory and dog demographic data to estimate the basic reproduction number, R0, as 5·9 (95% C.L. 4·4–7·4). R0 is a determinant of the scale of the leishmaniasis control problem, and we comment on the options for control.

Item Type: Article
Copyright, Publisher and Additional Information: © 1997 Cambridge University Press
Keywords: canine leishmaniasis, Leishmania infantum, serology, domestic dog, incidence rate; basic reproduction number
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Biological Sciences (Leeds) > Institute of Integrative and Comparative Biology (Leeds)
Depositing User: Repository Officer
Date Deposited: 07 Jun 2006
Last Modified: 06 Jun 2014 19:24
Published Version: http://dx.doi.org/10.1017/S0031182097001200
Status: Published
Publisher: Cambridge University Press
Refereed: Yes
Identification Number: 10.1017/S0031182097001200
URI: http://eprints.whiterose.ac.uk/id/eprint/1260

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