215 research outputs found
Risk factors for Plasmodium falciparum hyperparasitaemia in malarious children
Background: Hyperparasitaemia is a feature of childhood severe malaria but there is little information on the risk
factors for hyperparasitaemia in malarious children
Methods: The risk factors associated with Plasmodium falciparum hyperparasitaemia, defined as asexual
parasitaemia > 250,000/ÎŒl, at presentation were evaluated in 3338 malarious children enrolled prospectively
between 2008 and 2010 in an endemic area of southwestern Nigeria.
Results: At enrolment, 97 (3%) of 3338 malarious children had hyperparasitaemia. In a multiple regression model, 3
factors were found to be independent risk factors for the presence of hyperparasitaemia at enrolment: an age †11
years (Adjusted odds ratio [AOR] = 2.85, 95% confidence interval [CI] 1.23-6.61, P = 0.014), fever (AOR = 2.02, 95%
CI 1.23-3.29, P = 0.005), and enrolment after year 2008 (AOR = 0.42, 95% CI 0.24-0.73, P = 0.002). Duration of illness
†3 d was associated with increased risk of hyperparasitaemia. There was no association between season and
hyperparasitaemia. Compared to non-hyperparasitaemia, hyperparasitaemia was associated with an increased risk of
progression to cerebral malaria (P < 0.0001). The risk of progression in hyperparasitaemic children was higher in <
5-year olds (P = 0.02).
Conclusion: Young age and presence of fever are independent risk factors for hyperparasitaemia which is
associated with an increased risk of progression to cerebral malaria. The findings have implications for case and
community management of childhood hyperparasitaemia and for malaria control efforts in sub-Saharan Africa
where severe malaria is relatively common
Factors contributing to delay in parasite clearance in uncomplicated falciparum malaria in children
Background: Drug resistance in Plasmodium falciparum is common in many endemic and other settings but there
is no clear recommendation on when to change therapy when there is delay in parasite clearance after initiation
of therapy in African children.
Methods: The factors contributing to delay in parasite clearance, defined as a clearance time > 2 d, in falciparum
malaria were characterized in 2,752 prospectively studied children treated with anti-malarial drugs between 1996
and 2008.
Results: 1,237 of 2,752 children (45%) had delay in parasite clearance. Overall 211 children (17%) with delay in
clearance subsequently failed therapy and they constituted 72% of those who had drug failure, i.e., 211 of 291
children. The following were independent risk factors for delay in parasite clearance at enrolment: age less than or
equal to 2 years (Adjusted odds ratio [AOR] = 2.13, 95% confidence interval [CI]1.44-3.15, P < 0.0001), presence of
fever (AOR = 1.33, 95% CI = 1.04-1.69, P = 0.019), parasitaemia >50,000/ul (AOR = 2.21, 95% CI = 1.77-2.75,
P < 0.0001), and enrolment before year 2000 (AOR= 1.55, 95% CI = 1.22-1.96, P < 0.0001). Following treatment,
a body temperature ℠38°C and parasitaemia > 20000/Όl a day after treatment began, were independent risk
factors for delay in clearance. Non-artemisinin monotherapies were associated with delay in clearance and
treatment failures, and in those treated with chloroquine or amodiaquine, with pfmdr 1/pfcrt mutants. Delay in
clearance significantly increased gametocyte carriage (P < 0.0001).
Conclusion: Delay in parasite clearance is multifactorial, is related to drug resistance and treatment failure in
uncomplicated malaria and has implications for malaria control efforts in sub-Saharan Africa
Effects of mefloquine and artesunate mefloquine on the emergence, clearance and sex ratio of Plasmodium falciparum gametocytes in malarious children
<p>Abstract</p> <p>Background</p> <p>The gametocyte sex ratio of <it>Plasmodium falciparum</it>, defined as the proportion of gametocytes that are male, may influence transmission but little is known of the effects of mefloquine or artesunate-mefloquine on gametocyte sex ratio and on the sex ratio of first appearing gametocytes.</p> <p>Methods</p> <p>350 children with uncomplicated <it>P. falciparum </it>malaria were enrolled in prospective treatment trial of mefloquine or artesunate-mefloquine between 2007 and 2008. Gametocytaemia was quantified, and gametocytes were sexed by morphological appearance, before and following treatment. The area under curve of gametocyte density <it>versus </it>time (AUC<sub>gm</sub>) was calculated by linear trapezoidal method.</p> <p>Results</p> <p>91% and 96% of all gametocytes appeared by day 7 and day 14, respectively following treatment. The overall rate of gametocytaemia with both treatments was 31%, and was significantly higher in mefloquine than in artesunate-mefloquine treated children if no gametocyte was present a day after treatment began (25.3% <it>v </it>12.8%, P = 0.01). Gametocyte clearance was significantly faster with artesunate-mefloquine (1.8 ± 0.22 [sem] <it>v </it>5.6 ± 0.95 d; P = 0.001). AUC<sub>gm </sub>was significantly lower in the artesunate mefloquine group (P = 0.008). The pre-treatment sex ratio was male-biased, but post-treatment sex ratio or the sex ratio of first appearing gametocytes, was significantly lower and female-biased two or three days after beginning of treatment in children given artesunate-mefloquine.</p> <p>Conclusion</p> <p>Addition of artesunate to mefloquine significantly modified the emergence, clearance, and densities of gametocytes and has short-lived, but significant, sex ratio modifying effects in children from this endemic area.</p
Le projet "Dahomey Gap": une contribution à l'histoire de la végétation au Sud-Bénin et Sud-ouest du Nigéria
La coupure que l'on constate dans les forĂȘts denses africaines au niveau du Togo et du BĂ©nin soulĂšve de nombreuses questions sur les rapports forĂȘt/savane au cours des derniers millĂ©naires. Le projet Dahomey Gap vise Ă y rĂ©pondre, par une approche pluridisciplinaire intĂ©grant botanique et histoire de la vĂ©gĂ©tation dans le Sud-BĂ©nin et le Sud-Ouest du NigĂ©ria. A partir de travaux dĂ©jĂ avancĂ©s sur la vĂ©gĂ©tation du BĂ©nin et des premiĂšres prospections palynologiques, quelques aspects du projet sont exposĂ©s ici: tels la caractĂ©risation des diffĂ©rentes formations forestiĂšres du BĂ©nin, les premiers rĂ©sultats sur l'histoire holocĂšne de la vĂ©gĂ©tation du Sud-BĂ©nin (mangroves, forĂȘts, savanes) enregistrĂ©e depuis prĂšs de 7000 ans dans les lagunes
Early Changes in Plasmodium falciparum Asexual and Sexual Populations in Children with Acute Infections Following Treatment with Artemisinin-Based Combination Drugs
Artemisinin-based combination therapies (ACTs)
may influence malaria transmission but the early changes
in parasite populations have not been frequently evaluated.
The changes in Plasmodium falciparum asexual and sexual
populations in the first 16 h following treatment with
artemether-lumefantrine (AL) or artesunate-amodiaquine
(AA) were evaluated in 443 children with acute infections.
The effects of gametocyte density on gametocyte sex ratio
(GSR) were characterized in another cohort of 52 children
treated with AL and AA. Stages of asexual and sexual
parasites in peripheral blood were determined morphologically.
In 167 children there were significant increases in
peripheral asexual parasitemia at 1 h, and in 15 of these,
an insignificant increase in gametocytemia at 1 h, followed
thereafter by a precipitous and significant fall in all patients.
Time-course of GSR showed a female-male-female-biased
cycle at 0 h, 4 h, and 8 h. Pre-treatment GSR and time-course
of GSR post-treatment were independent of density in the
additional cohort of 52 gametocyte carriers treated with AL
or AA. Population changes were similar in AL- and AAtreated
children. Treatment with AL or AA is associated
with early increases in asexual and sexual parasites and is
closely followed by rapid elimination of these parasites
A Simple Dose Regimen of Artesunate and Amodiaquine Based on Age or Body Weight Range for Uncomplicated Falciparum Malaria in Children: Comparison of Therapeutic Efficacy With Standard Dose Regimen of Artesunate and Amodiaquine and ArtemetherâLumefantrine
A new dose regimen of artesunate and amodiaquine (NDRAA) based on age or body weight range was compared with standard dose regimen of artesunate and amodiaquine (SDRAA) calculated according to body weight and with fixed-dose artesunateâamodiaquine (FDAA) and artemetherâlumefantrine (AL) in 304 children afflicted by malaria aged 15 years or younger. In initial comparison (n = 208), children on NDRAA received 1â3 times amodiaquine per kilogram of body weight and 1â1.5 times of artesunate per kilogram of body weight compared with those receiving SDRAA. Parasite but not fever clearance was significantly faster in children who received NDRAA (19.4 ± 8.4 hours vs. 24.6 ± 15.5 hours, P = 0.003). Polymerase chain reactionâuncorrected cure rates on days 28â42 were also significantly higher in children who received NDRAA (P < 0.02 in all cases). Therapeutic responses in children younger than 5 years (n = 96) treated with NDRAA, FDAA, and AL were similar. Changes in hematocrit values and reported adverse events after commencing therapy were similar in those who received NDRAA and SDRAA. All drug regimens were well tolerated. NDRAA based on age or body weight range is simple, is therapeutically superior to SDRAA calculated according to body weight, and is as efficacious as AL in children younger than 5 years
Influence of Family Structure on Adolescent Sexual Behaviour in Mushin Local Government Area of Lagos State, Nigeria
The study investigates the influence of family structure on adolescent sexual behaviour in Mushin Local Government Area of Lagos State, Nigeria. The research was conducted by taking a sample of 330 adolescents who are 15-24 years. The analytical techniques used in the study are: univariate, bivariate and chi-square tests. The key findings of this study are: firstly, there are two types of family structures identified which include: in-tact and divorced families. Secondly, that the in-tact (at p=0.000) has significant influence on adolescent sexual behaviour. Thirdly, at p=0.000, it was observed that divorced family has significant effect on adolescent sexual behaviour. The recommendations for this study are that there is urgent strong counsel for folks in Nigerian society at large to shun divorce and value marriages thereby having more intact-homes which will curtail to a large extent immoral sexual behaviour among the adolescents
Therapeutic Efficacy and Effects of Artesunate-Mefloquine and Mefloquine Alone on Malaria-Associated Anemia in Children with Uncomplicated Plasmodium falciparum Malaria in Southwest Nigeria
The treatment efficacy and effects of artesunate-mefloquine (AMQ) and mefloquine (MQ) on malariaassociated
anemia (MAA) were evaluated in 342 children †10 years of age with uncomplicated Plasmodium falciparum
malaria randomized to receive either drug/drug combination. All children recovered clinically. Fever clearance times were
similar. Parasite clearance was significantly faster with AMQ (mean ± SD = 1.4 ± 0.6 days, 95% confidence interval [CI] =
1.3â1.5, P < 0.0001), but polymerase chain reactionâcorrected cure rates were similar (97% versus 94%). Gametocyte carriage
rates and the drug-attributable fall in hematocrit were significantly lower with AMQ (mean ± SD = 4.8 ± 3.8%, 95%
CI = 3.6â6.0, P = 0.03), but the rates of resolution of MAA were similar. Both regimens were well tolerated. AMQ clears
parasitemia and reduces gametocyte carriage more rapidly and causes lesser fall in hematocrit than MQ, but both regimens
are effective treatment of uncomplicated P. falciparum malaria in Nigerian children
Use of area under the curve to evaluate the effects of antimalarial drugs on malaria associated anemia after treatment
To evaluate the effects of antimalarial drugs on Plasmodium falciparum malaria associated anemia
(MAA), we use the area under curve (AUC) of anemia levels after treatment as an approach to
combine their duration and magnitude. The method involves numerical estimation, by trapezoidal
rule, of AUC from a plot of deficit in hematocrit levels from 30% (the lower threshold of normal)
versus time in anemic children. Using the method, we evaluated, in randomized trials, the effects
of artesunate-mefloquine (AMQ) versus mefloquine alone (MQ), and artemether-lumefantrine
(AL) versus amodiaquine-artesunate (AA) on the time-course of recovery from MAA in 109
children. Anemia resolution times were similar (10.9 ± 6.2 [SD] vs 13.3 ± 8.9 d, P = 0.2) but mean
AUC was significantly lower in AMQ- compared to MQ- treated children (35.5 ± 7.1 [SEM] vs
49.8 ± 11.3 %.h, P = 0.02) indicating larger exposure to anemia in MQ-treated children. In ALand
AA- treated children, both anemia resolution times (8.6 ± 5.3 [SD] vs 8.6 ± 4.8 d, P = 0.98)
and mean AUC (57.1 ± 12.9 [SEM] vs 46.3 ± 8.7 %.h, P = 0.74) were similar. Estimation of AUC
appears more robust than estimation of anemia resolution time in evaluating antimalarial drug
effects and can be used in both observational studies and clinical trials assessing the effects of
therapies on MAA
Plasmodium falciparum gametocyte carriage, emergence, clearance and population sex ratios in anaemic and non-anaemic malarious children
Anaemia in falciparum malaria is associated with an increased risk of gametocyte carriage, but its effects on transmission have not been extensively evaluated in malarious children. Plasmodium falciparum gametocyte carriage, emergence, clearance, population sex ratios (SR) (defined as the proportion of gametocytes that are male), inbreeding rates and temporal changes in SR were evaluated in 840 malarious children. Gametocyte carriage pre-treatment was at a level of 8.1%. Anaemia at enrolment was an independent risk factor for gametocyte carriage post-treatment. The emergence of gametocytes seven days post-treatment was significantly more frequent in anaemic children (7/106 vs. 10/696, p = 0.002). In the initially detected gametocytes, the proportion of children with a male-biased SR (MBSR) (> 0.5) was significantly higher in anaemic children (6/7 vs. 3/10, p = 0.027). Pre-treatment SR and estimated inbreeding rates (proportion of a motherâs daughters fertilised by her sons) were similar in anaemic and non-anaemic children. Pre-treatment SR became more female-biased in non-anaemic children following treatment. However, in anaemic children, SR became male-biased. Anaemia was shown to significantly increase gametocyte emergence and may significantly alter the SR of emerging gametocytes. If MBSR is more infective to mosquitoes at low gametocytaemia, then these findings may have significant implications for malaria control efforts in endemic settings where malaria-associated anaemia is common
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