A. A. A. Alaribe

Artemether-lumefantrine versus artesunate plus amodiaquine for treating uncomplicated childhood malaria in Nigeria: randomized controlled trial.

BackgroundThe therapeutic efficacy of artesunate plus amodiaquine and artemether/lumefantrine were assessed in an area of Nigeria with high levels of Plasmodium falciparum resistance to chloroquine and sulphadoxine-pyrimethamine.ParticipantsChildren aged 6 to 59 months with uncomplicated P. falciparum infection and parasite density 1,000 to 200,000 parasites/μL enrolled following informed consent by parents.MethodsEligible children were randomly assigned to receive either a 3-day course of artesunate (4 mg/kg) plus amodiaquine (10 mg/kg) or 6-dose course of artemether/lumefantrine (20/120 mg tablets) over three days. Patients were followed up with clinical and laboratory assessments until day 14 using standard WHO in-vivo antimalarial drug test protocol.ResultsA total 119 eligible children were enrolled but 111 completed the study. Adequate clinical and parasitological response (ACPR) was 47 (87.0%) and 47 (82.5%) for artemether-lumefantrine (AL) and artesunate+amodiaquine (AAMQ) respectively (OR 0.7, 95% confidence interval 0.22 to 2.22). Early treatment failure (ETF) occurred in one participant (1.8%) treated with AAQ but in none of those with AL. Two (3.7%) patients in the AL group and none in the AAQ group had late clinical failure. Late parasitological failure was observed in 9 (15.8) and 5 (9.3%) of patients treated with AAQ and AL respectively. None of participants had a serious adverse event.ConclusionArtemether-lumenfantrine and artesunate plus amodiaquine have high and comparable cure rates and tolerability among under-five children in Calabar, Nigeria.

Malaria and its treatment in rural villages of Aboh Mbaise, Imo State, Nigeria.

We examined the malaria situation among 489 children under 5 years of age in the rural villages of Aboh Mbaise, Nigeria, using a combination of a standard questionnaire technique and laboratory diagnosis to confirm clinical observations. The results show a high prevalence rate of 52.8% for Plasmodium falciparum in this area. The geometric mean parasite density (GMPD) was 19,361.4/mm3. The proportion of children with fever and/or parasitaemia was not related to age, although the numbers in the febrile group appeared to increase with age. Using 37.5 degrees C as the threshold for fever, 48.7% of the heavily infected group (more than 1000/mm3) were afebrile while 51.3% were febrile. High grade temperatures above 38 degrees C were associated with high parasitaemia above 10,000 parasites/mm3. Of the 911 children who died in the area within the last five years, 22.4% died of fever of unknown origin, 39.7% from malaria, 22.5% from convulsion, 10.5% from diarrhoea and 4.6% from cough. Chloroquine is the drug of choice for the treatment of malaria and there were many cases of drug abuse, and use of sub-curative doses prescribed by non-medically qualified staff.

The distribution of M and S molecular forms of Anopheles gambiae in Nigeria

The distribution of M and S molecular forms of Anopheles gambiae sensu stricto across Nigeria was determined. The molecular form of 40 to 45 specimens per locality from 9 localities was determined using mostly the same specimens from our recent study of genetic differentiation of A. gambiae across Nigeria (Onyabe & Conn, 2001). These samples were previously genotyped at 10 microsatellite loci, 5 located within chromosome inversions and 5 outside inversions. Both molecular forms occurred throughout the country, with no apparent relationship to the ecological transition from dry savannah in the north to humid forest in southern Nigeria. In all localities, however, 1 form or the other occurred virtually exclusively. No hybrids between forms were found. Across all loci, F(ST) values were as high within molecular forms as between forms. Regardless of molecular form, F(ST) values calculated across loci within inversions were much higher (range 0.0016 to 0.1988) than those calculated across loci outside inversions (range -0.0035 to 0.0260). Genetic distance was not significantly correlated with geographical distance within either form (P> 0.05). These observations suggest that, in addition to partial reproductive barriers between molecular forms, selection is a major factor shaping genetic differentiation of A. gambiae across Nigeria.

Open-label trial of three dosage regimens of fixed-dose combination of artemisinin and naphthoquine for treating uncomplicated falciparum malaria in calabar, Nigeria

BackgroundThe use of anti-malarial drug combinations with artemisinin, or with one of its derivatives, is now widely recommended to overcome drug resistance in falciparum malaria. Fixed-dose combination of artemisinin and naphthoquine is a new generation artemisinin combination therapy (ACT) offered as a single dose therapy. The aim of the study was to assess the therapeutic efficacy, safety and tolerability of three dosage schedules of fixed-dose combination of artemisinin (125 mg) and naphthoquine (50 mg) for treating uncomplicated Plasmodium falciparum malaria among adolescents and adults in Calabar, South-east Nigeria.MethodA total of 121 patients aged ≥15 years with uncomplicated P. falciparum malaria were enrolled and randomly assigned to three dosage schedules: (A) 700 mg (four tablets) single dose; (B) 700 mg 12-hourly x two doses; and (C) 1,400 mg (eight tablets) single dose. Patients were observed for 28 days, with clinical, parasitological, and haematological assessments.ResultsA total of 108 patients completed the study. The overall 28-day cure rate was 88.9%. Day 28-cure rates of the three dosage schedules were 85.3%, 93.1% and 88.9% for Group A, B and C respectively. Adverse events were few and mild, the commonest being weakness and headache; there was no serious adverse event.ConclusionConcerns for emergence of parasite resistance due to the use of artemisinin-naphthoquine as single dose regimen is likely to compromise the usefulness of this potentially important combination treatment. A robust multi-centre trial is recommended to evaluate a three-day regimen with potentials to achieve high cure rates while minimizing the risk of emergence of resistant parasite strains.

The Role of Kola Nut (Cola Nitida) in the Etiology of Malaria Morbidity

The contribution of kola nut in mimicking malaria-like morbidity in apparently healthy volunteers was evaluated. Thirty-five grams of Cola nitida was given to each of the 48 volunteers who were known not to have taken kola nut or coffee in the previous one month for three consecutive days. The blood samples of these volunteers were enumerated for malaria parasites before serving them the kola nut. The sampling of blood was repeated on the 2nd and 3rd days for the presence of malaria parasites. Blood samples were also taken from known kola nut addicts (those that eat kola nut on daily basis). It was found that 16 (33.3%) of the volunteers had malaria parasites in their blood at the inception of the study while 32 (66.7%) had no detectable parasites. Four days after, 10 (20.8%) of the volunteers that did not show detectable parasites on the first day now had parasites. Those that showed detectable parasite before taking the kola had significant increase in parasite density. Statistical analysis showed a strong relationship between parasite increase and eating of the kola nut (Chi-squared, X 2 = 14.83, p > 0.0001 at 95% confidence limit). The volunteers reported clinical symptoms of sleeplessness, lack of concentration, dizziness, and weakness observable in malaria patients. There was no association between malaria parasite presence and clinical complaints (X 2 = 3.75, df = 1, p = 0.05). It was found that 11 people without the malaria parasite in their blood before and after taking the kola nut complained of various malaria symptoms confirming that kola nut can mimic malaria-like symptoms. In conclusion, it can be said that kola nut taken at a high concentration (about 35 g/day) will mimic malaria-like symptoms. This quantity will leave a high level of caffeine and cyanide in the circulation so that people with a low level of malaria parasite in them will notice active infection which otherwise may have been controlled by the host immune system. Lastly, the observed phenomenon can affect drug pressure and induce resistance to antimalarial drugs. The mechanism of kola nut action that influences malaria-like morbidity is discussed.

CHLOROQUINE PHOSPHATE SUPPOSITORIES IN THE TREATMENT OF CHILDHOOD MALARIA IN CALABAR, NIGERIA

In a randomized, prospective study of the therapy of acute falciparum malaria in 69 children, aged 6 to 60 months, the results of treatment with chloroquine phosphate suppositories (30 patients) and chloroquine sulfate syrup (39 patients) were compared. Each patient received 25mg chloroquine base/kg body weight over 3 consecutive days (day 0,lO mgkg; day 1,lO mg/kg; and day 2, 5 mg/kg). The parasitologic cure rate was 33% (lo/301 in the chloroquine phosphate suppository group and 36% (14/39) in the chloroquine sulfate syrup group. In addition, the mean pretreatment parasite counts of the chloroquinesensitive cases were not significantly different in the two groups. However, pyrexia resolved slightly more slowly in the suppository group, although all sensitive patients in both groups were afebrile on day 3. The results suggest that chloroquine phosphate suppositories are as effective as chloroquine sulfate syrup in the treatment of children with malaria caused by chloroquine-sensitive Plasmodium fakiparum.