Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-29T01:06:08.919Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Published online by Cambridge University Press:  01 August 1997

R. J. QUINNELL ,
O. COURTENAY ,
L. GARCEZ  and
C. DYE
R. J. QUINNELL
Affiliation:
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT
O. COURTENAY
Affiliation:
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT
L. GARCEZ
Affiliation:
Instituto Evandro Chagas, CP1128, Belém 66050, Pará, Brazil
C. DYE
Affiliation:
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT
Get access Rights & Permissions [Opens in a new window]

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 8·66×10−3/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.

Keywords

canine leishmaniasisLeishmania infantumserologydomestic dogincidence ratebasic reproduction number
Type
Research Article
Information
Parasitology , Volume 115 , Issue 2 , August 1997 , pp. 143 - 156
Copyright
1997 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)