Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment

OBJECTIVE: Parasites may recur asymptomatically after initial clearance by antimalarial treatment. Current guidelines recommend treatment only when patients develop symptoms or at the end of follow-up. We wanted to assess prospectively the probability of becoming symptomatic and the risks of this pr...

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Main Authors: Olliaro, P., Pinoges, L., Checchi, F., Vaillant, M., Guthmann, J. P.
Format: Journal Article
Language:EN
Published: 2012
Subjects:
Online Access:http://hdl.handle.net/10986/5118
id okr-10986-5118
recordtype oai_dc
spelling okr-10986-51182021-04-23T14:02:21Z Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment Olliaro, P. Pinoges, L. Checchi, F. Vaillant, M. Guthmann, J. P. Antimalarials Preschool Child Female Humans Infant Logistic Models Malaria/*drug therapy/parasitology/*physiopathology/prevention & control Male Parasitemia control Proportional Hazards Models Recurrence Risk Factors OBJECTIVE: Parasites may recur asymptomatically after initial clearance by antimalarial treatment. Current guidelines recommend treatment only when patients develop symptoms or at the end of follow-up. We wanted to assess prospectively the probability of becoming symptomatic and the risks of this practice. METHODS: We analysed data collected in 13 trials of uncomplicated paediatric malaria conducted in eight sub-Saharan African countries. These studies followed all cases of post-treatment asymptomatic parasitaemia until they developed symptoms or to the end of the 28-day follow-up period, at which time parasite genotypes were compared to pre-treatment isolates to distinguish between recrudescences and new infections. RESULTS: There were 425 asymptomatic recurrences after 2576 treatments with either chloroquine, sulfadoxine/pyrimethamine or amodiaquine, of which 225 occurred by day 14 and 200 between day 15 and day 28. By day 28, 42% developed fever (median time to fever = 5 days) and 30% remained parasitaemic but afebrile, while 23% cleared their parasites (outcome unknown in 4%). Young age, parasitaemia >/=500 parasites/microl; onset of parasitaemia after day 14, and treatment with amodiaquine were the main variables associated with higher risk of developing fever. CONCLUSION: In areas of moderate to intense transmission, asymptomatic recurrences of malaria after treatment carry a substantial risk of becoming ill within a few days and should be treated as discovered. Young children are at higher risk. The higher risk carried by cases occurring in the second half of follow-up may be explained by falling residual drug levels. 2012-03-30T07:31:23Z 2012-03-30T07:31:23Z 2008 Journal Article Trop Med Int Health 1365-3156 (Electronic) 1360-2276 (Linking) http://hdl.handle.net/10986/5118 EN http://creativecommons.org/licenses/by-nc-nd/3.0/igo World Bank Journal Article
repository_type Digital Repository
institution_category Foreign Institution
institution Digital Repositories
building World Bank Open Knowledge Repository
collection World Bank
language EN
topic Antimalarials
Preschool Child
Female
Humans
Infant
Logistic Models
Malaria/*drug therapy/parasitology/*physiopathology/prevention & control
Male
Parasitemia
control
Proportional Hazards Models
Recurrence
Risk Factors
spellingShingle Antimalarials
Preschool Child
Female
Humans
Infant
Logistic Models
Malaria/*drug therapy/parasitology/*physiopathology/prevention & control
Male
Parasitemia
control
Proportional Hazards Models
Recurrence
Risk Factors
Olliaro, P.
Pinoges, L.
Checchi, F.
Vaillant, M.
Guthmann, J. P.
Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
relation http://creativecommons.org/licenses/by-nc-nd/3.0/igo
description OBJECTIVE: Parasites may recur asymptomatically after initial clearance by antimalarial treatment. Current guidelines recommend treatment only when patients develop symptoms or at the end of follow-up. We wanted to assess prospectively the probability of becoming symptomatic and the risks of this practice. METHODS: We analysed data collected in 13 trials of uncomplicated paediatric malaria conducted in eight sub-Saharan African countries. These studies followed all cases of post-treatment asymptomatic parasitaemia until they developed symptoms or to the end of the 28-day follow-up period, at which time parasite genotypes were compared to pre-treatment isolates to distinguish between recrudescences and new infections. RESULTS: There were 425 asymptomatic recurrences after 2576 treatments with either chloroquine, sulfadoxine/pyrimethamine or amodiaquine, of which 225 occurred by day 14 and 200 between day 15 and day 28. By day 28, 42% developed fever (median time to fever = 5 days) and 30% remained parasitaemic but afebrile, while 23% cleared their parasites (outcome unknown in 4%). Young age, parasitaemia >/=500 parasites/microl; onset of parasitaemia after day 14, and treatment with amodiaquine were the main variables associated with higher risk of developing fever. CONCLUSION: In areas of moderate to intense transmission, asymptomatic recurrences of malaria after treatment carry a substantial risk of becoming ill within a few days and should be treated as discovered. Young children are at higher risk. The higher risk carried by cases occurring in the second half of follow-up may be explained by falling residual drug levels.
format Journal Article
author Olliaro, P.
Pinoges, L.
Checchi, F.
Vaillant, M.
Guthmann, J. P.
author_facet Olliaro, P.
Pinoges, L.
Checchi, F.
Vaillant, M.
Guthmann, J. P.
author_sort Olliaro, P.
title Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
title_short Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
title_full Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
title_fullStr Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
title_full_unstemmed Risk Associated with Asymptomatic Parasitaemia Occurring Post-Antimalarial Treatment
title_sort risk associated with asymptomatic parasitaemia occurring post-antimalarial treatment
publishDate 2012
url http://hdl.handle.net/10986/5118
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