Obaro S Michael

Therapeutic Efficacy and Effects of Artemether-Lumefantrine and Artesunate-Amodiaquine Coformulated or Copackaged on Malaria-Associated Anemia in Children with Uncomplicated Plasmodium falciparum Malaria in Southwest Nigeria

The therapeutic efficacy and effects of artemether-lumefantrine (AL) and artesunate-amodiaquine co-formulated (AAcf) or co-packaged (AAcp) on malaria-associated anemia (MAA) were evaluated in 285 children < 12 years of age with uncomplicated Plasmodium falciparum malaria randomized to receive one of the three drug combinations. Fever and parasite clearance times were similar in all treatment groups. Mean drug-attributable fall in hematocrit (DAFH), defined as difference between hematocrit values pre- and 3 d post-initiation of treatment, was low (< 4.5%) and rates of recovery from MAA were similar with all treatments. Mean areas under curve (AUCs) of the plot of deficit in hematocrit levels from 30% versus time in anemic children were similar in all groups. All regimens were well tolerated. AL, AAcf and AAcp cleared fever and parasitemia rapidly and had similar rates of resolution of MAA after treatment in malarious Nigerian children.

Early variations in plasmodium falciparum dynamics in Nigerian children after treatment with two artemisinin-based combinations: implications on delayed parasite clearance

BackgroundCombination treatments, preferably containing an artemisinin derivative, are recommended to improve efficacy and prevent Plasmodium falciparum drug resistance. Artemether-lumefantrine (AL) and artesunate-amodiaquine (AA) are efficacious regimens that have been widely adopted in sub-Saharan Africa. However, most study designs ignore the effects of these regimens on peripheral parasitaemia in the first 24 hours of therapy. The study protocol was designed to evaluate more closely the early effects and the standard measures of efficacies of these two regimens.MethodsIn an open label, randomized controlled clinical trial, children aged 12 months to 132 months were randomized to receive AL (5-14 kg, one tablet; 15-24 kg, two tablets and 25-34 kg, three tablets twice daily) or artesunate (4 mg/kg daily) plus amodiaquine (10 mg/kg daily) for three days. Peripheral blood smears were made hourly in the first 4 hours, 8 h, 16 h, 24 h, and daily on days 2-7, and on days 7, 14, 21, 28, 35, and 42 for microscopic identification and quantification of Plasmodium falciparum.ResultsA total of 193 children were randomized to receive either AL (97) or AA (96). In children that received both medications, early response of peripheral parasitaemia showed that 42% of children who received AL and 36.7% of those who received AA had an immediate rise in peripheral parasitaemia (0-4 h after treatment) followed by a rapid fall. The rise in parasitaemia was significant and seems to suggest a mobilization of asexual parasites from the deep tissues to the periphery. Days 3, 7, 14, 28, and 42 cure rates in the per protocol (PP) population were > 90% in both groups of children. Both drug combinations were well tolerated with minimal side effects.ConclusionThe study showed the high efficacy of AL and AA in Nigerian children. In addition the study demonstrated the mobilisation of asexual parasites from the deep to the periphery in the early hours of commencing ACT treatment in a subset of patients in both study groups. It is unclear whether the early parasite dynamics discovered in this study play any role in the development of drug resistance and thus it is important to further evaluate this discovery. It may be useful for studies investigating delay in parasite clearance of artemisinin derivatives as a way of monitoring the development of resistance to artemisinin to assess the early effects of the drugs on the parasites.

Factors contributing to delay in parasite clearance in uncomplicated falciparum malaria in children

BackgroundDrug 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.MethodsThe 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.Results1,237 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/μl 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).ConclusionDelay 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.

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, we use the area under the curve (AUC) of anemia levels after treatment as an approach to combine their duration and magnitude. The method involves numeric 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 versus mefloquine alone and artemether-lumefantrine versus amodiaquine-artesunate on the time course of recovery from malaria-associated anemia in 109 children. Anemia resolution times were similar (10.9 ± 6.2 [standard deviation] versus 13.3 ± 8.9 days, P = 0.2), but mean AUC was significantly lower in artesunate-mefloquine- compared with mefloquine-treated children (35.5 ± 7.1 [standard error of mean] versus 49.8 ± 11.3 %·h, P = 0.02) indicating larger exposure to anemia in mefloquine-treated children. In artemether-lumefantrine- and amodiaquine-artesunate-treated children, both anemia resolution times (8.6 ± 5.3 [standard deviation] versus 8.6 ± 4.8 days, P = 0.98) and mean AUC (57.1 ± 12.9 [standard error of mean] versus 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 malaria-associated anemia.

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 mothers 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.

Therapeutic efficacy of artesunate-amodiaquine combinations and the plasma and saliva concentrations of desethylamodiaquine in children with acute uncomplicated Plasmodium falciparum malaria.

The treatment efficacy of artesunate–amodiaquine (AQ) coformulated or copackaged, and the plasma and saliva concentrations of desethylamodiaquine (DEAQ), the active metabolite of AQ, were evaluated in 120 and 7 children, respectively, with uncomplicated Plasmodium falciparum malaria treated with oral daily doses of the 2 formulations for 3 days. All children recovered clinically. Fever clearance (1.1 ± 0.2 vs 1.0 ± 0 days) and parasite clearance times (21.1 ± 10.2 vs 19.0 ± 7.0 hours) in artesunate–AQ coformulated and artesunate–AQ copackaged treated children, respectively, were similar. All children remained aparasitemic for at least 28 days. Blood and saliva samples were collected over 35 days and DEAQ in plasma and saliva was determined by high-performance liquid chromatography. DEAQ was detectable in plasma and saliva within 40 minutes of oral administration of artesunate–AQ. DEAQ concentrations 7 days after the start of therapy were 247.8 and 125.1 ng/mL in plasma and saliva, respectively. The concentration–time curves of plasma and saliva in declining phases were approximately parallel giving a similar half-life of 169.1 ± 16.4 and 142.8 ± 6.5 hours in plasma and saliva, respectively. Clearance from plasma and saliva was also similar (335.6 and 443.4 mL·h−1·kg−1, respectively). Area under concentration–time curves (AUC0–35d) for plasma and saliva were 94,744.9 and 74,004.2 ng·mL−1·h, respectively. In general, Saliva–plasma concentration ratio was 0.25–0.4. DEAQ concentrations in saliva may be useful for monitoring therapy and for the evaluation of the disposition of AQ in children with falciparum malaria treated with AQ-based combination.

HCV co-infection is associated with metabolic abnormalities among HAART naive HIV-infected persons

Objectives: To determine the metabolic abnormalities among Hepatitis C Virus (HCV) co infected HAART naïve HIV infected persons within the adult ARV clinic of the University College Hospital/University of Ibadan, Ibadan, Nigeria Methods: This was a retrospective study involving the review of clinical records of newly recruited HIV-infected persons in the adult antiretroviral (ARV) clinic over a 12 month period (January - December 2006). Baseline results for fasting plasma glucose (FPG) and fasting lipid profile were retrieved. Results: Out of the 1,260 HIV infected persons seen during the study period, HCV co-infection was found in 75 (6%) persons. The median values for total cholesterol, LDL-cholesterol and HDL-cholesterol were lower in the HCV co-infected persons. HIV-HCV co–infection was associated with a 0.31 mmol/L depression in Total Cholesterol (TC). The median FPG concentration was significantly higher in HIV-HCV co–infected than HIV only infected persons (5.33mmol/L vs. 5.00mmol/L, p = 0.047). However, regression analysis showed there was no relationship between the HIV-HCV co infected state and fasting glucose levels. Conclusion: HIV-HCV co-infection may be associated with a predictable decline in plasma cholesterol, but FPG may not be sufficient to demonstrate insulin resistance in these persons.

Seroprevalence and factors associated with hepatitis C coinfection among HIV‑positive pregnant women at the University College Hospital, Ibadan, Nigeria

Aim: This study estimated the hepatitis C virus (HCV) prevalence in a population of human immunodeficiency virus (HIV) infected pregnant women, compared women who were positive or negative for HCV and described risk factors associated with HCV infection. Materials and Methods: A retrospective, case control study was conducted at the University College Hospital, Ibadan among 1821 women. Twenty-six (1.65%) women were HCV positive, 139 (8.83%) were HBsAg positive and 1407 (89.33%) were negative for both viruses. Three patients (0.19%) were positive for both viruses. These patients, i.e., the HBsAg positive women and 246 women with no result, for either virus were excluded from analysis. Data from 1433 pregnant women is presented. Chi square test and student′s t-test examined associations, with level of significance set at P < 0.05. Results: Overall, the mean age of the HCV positive women was lower (26.77 ± 6.53 vs. 28. 95 years ± 5.33; P = 0.04), most women had attained primary (28.49%) or secondary (42.44%) education, over 90% were married and heterosexual sex (88.67%) was the most likely risk for HIV. HCV prevalence was higher in the lower age groups (5% in the ≤ 19 years group, P = 0.021). The coinfected had more unmarried women (3.6% vs. 1.7%; P = 0.164) and more likely to indicate blood transfusion as a risk factor for HIV (6.2%; P = 0.34). Conclusion: Only age showed any significant association with HCV infection. Lack of identifiable risk factors sum up challenges for developing screening strategies in sub-Saharan Africa. Further studies will identify factors facilitating HCV transmission in the region.