Low-dose quinine for treatment of Plasmodium falciparum malaria in Guinea-Bissau

Malaria transmission in Bissau, Guinea-Bissau between 1995 and 2012: malaria resurgence did not negatively affect mortality

Introduction

As Plasmodium falciparum prevalence decreases in many parts of Sub-Saharan Africa, so does immunity resulting in larger at risk populations and increased risk of malaria resurgence. In Bissau, malaria prevalence decreased from ∼50% to 3% between 1995 and 2003. The epidemiological characteristics of P. falciparum malaria within Bandim health and demographic surveillance site (population ∼100000) between 1995 and 2012 are described.

Methods and Findings

The population was determined by census. 3603 children aged <15 years that were enrolled in clinical trials at the Bandim health centre (1995–2012) were considered incident cases. The mean annual malaria incidence per thousand children in 1995–1997, 1999–2003, 2007, 2011, 2012 were as follows; age <5 years 22→29→4→9→3, age 5–9 years 15→28→4→33→12, age 10–14 years 9→15→1→45→19. There were 4 campaigns (2003–2010) to increase use of insecticide treated bed nets (ITN) amongst children <5 years. An efficacious high-dose chloroquine treatment regime was routinely used until artemisinin based combination therapy (ACT) was introduced in 2008. Long lasting insecticide treated bed nets (LLIN) were distributed in 2011. By 2012 there was 1 net per 2 people and 97% usage. All-cause mortality decreased from post-war peaks in 1999 until 2012 in all age groups and was not negatively affected by malaria resurgence.

Conclusion

The cause of decreasing malaria incidence (1995–2007) was probably multifactorial and coincident with the use of an efficacious high-dose chloroquine treatment regime. Decreasing malaria prevalence created a susceptible group of older children in which malaria resurged, highlighting the need to include all age groups in malaria interventions. ACT did not hinder malaria resurgence. Mass distribution of LLINs probably curtailed malaria epidemics. All-cause mortality was not negatively affected by malaria resurgence.

Continued efficacy of sulfadoxine-pyrimethamine as second line treatment for malaria in children in Guinea-Bissau

BACKGROUND

Sulfadoxine-pyrimethamine (S/P) is widely used for treatment of failures following the first line treatment for malaria in Africa. In Guinea-Bissau, it has been recommended as second line therapy by the National Malaria Programme since 1996. In order to monitor any change of the in vivo sensitivity, the efficacy of S/P was studied immediately before the introduction of the drug and 6-9 years later.

METHODS

Children participating in clinical in vivo studies were given S/P if having late clinical treatment failure following the treatment with quinine, chloroquine, or amodiaquine. Parasitological and clinical failures were evaluated during a 35-day follow-up. During the first study period whole blood sulfadoxine concentrations were measured on day 7.

RESULTS

Altogether, 56 children failed the initial treatment and were included in 1995/1996 as well as 55 children in 2002/2004. The PCR-uncorrected adequate clinical and parasitological response rates on day 28 were 94% and 91%, and on day 35 they were 89% and 91%, respectively, in the two periods. No difference between median blood drug concentration in children with and without treatment failure was observed.

INTERPRETATION

The efficacy of S/P as second line treatment for uncomplicated malaria has remained unchanged in spite of a relatively high level of genetic markers associated with Plasmodium falciparum resistance to S/P previously found in the area.

No benefits from combining chloroquine with artesunate for three days for treatment of Plasmodium falciparum in Guinea-Bissau

The use of a combination of chloroquine and artesunate has been suggested for treatment of malaria in Africa. We used concomitant as well as sequential medication with these 2 drugs in relation to each drug separately for children infected with Plasmodium falciparum in Guinea-Bissau from March 2000 to November 2001. By block-randomization, 474 children with symptomatic malaria were divided into 4 groups and given either a total of 8 mg artesunate per kg bodyweight for 3 d, a total of 25 mg chloroquine base per kg bodyweight for 3 d, both drugs concomitantly for 3 d, or both drugs in sequence. All children were followed weekly for 5 weeks. On day 28, parasites had been detected in 40% of the children who were treated with artesunate only compared with 21% treated with chloroquine, 20% treated with artesunate in combination with chloroquine, and 16% treated with artesunate and chloroquine in sequence; on day 35 the corresponding percentages were 48%, 29%, 27%, and 24%, respectively. The outcome of the combination of chloroquine and artesunate in the doses studied was similar to the outcome of chloroquine monotherapy regardless of whether the 2 drugs are given concomitantly (relative risk [RR] = 0.93, 95% CI 0.56-1.53, P = 0.76) or in sequence (RR = 0.78, 95% CI 0.47-1.28, P = 0.32). Thus, neither an antagonistic, an additive, or a synergistic effect of the 2 drugs was indicated.

Low-dose quinine is effective in the treatment of chloroquine-resistant Plasmodium falciparum malaria in eastern Sudan

In November-December 2002, 98 patients presented at the Elhara Eloula health centre, in the New Halfa area of eastern Sudan, with Plasmodium falciparum malaria that had failed to respond to chloroquine treatment. After informed consent was obtained, 93 of these patients were randomly allocated to one of three regimens for quinine treatment, being given the drug, orally and sometimes intravenously, for 7 days, at doses of 10 mg/kg thrice daily (32 patients), 10 mg/kg twice daily (31 patients) or 15 mg/kg once daily (30 patients). All the patients were followed daily until day 7 and then weekly until day 28. There was no significant difference in the parasite-clearance times observed in the three groups. Parasitaemias re-occurred by day 28 in 12 patients: two (6.3%) of the patients treated thrice daily, five (16.1%) of those treated twice daily, and five (16.7%) of those treated once daily (P > 0.05). Genotyping indicated that in nine of these 12 patients the parasitaemias that developed post-treatment represented true recrudescences and not re-infections. In the treatment of chloroquine-resistant, P. falciparum malaria in Sudan, once-daily treatment with quinine, in a relatively low daily dose (15 mg/kg. day), appears as effective as the thrice-daily treatment (at 30 mg/kg. day) often recommended.

Can mothers be trusted to give malaria treatment to their children at home?

Children with symptomatic malaria in Bissau were randomly assigned to treatment with chloroquine 25 mg base/kg given supervised at a health centre or unsupervised by the mothers at home. On day 7, a blood sample for drug analyses was drawn and the children were then followed once weekly for 5 weeks. The data were analysed on an intention to treat basis. No differences were seen in the outcome of treatment nor in the blood drug concentrations on day 7 between the two groups. Mothers in Bissau can be trusted to give adequate anti-malarial medication to their children at home.

Treatment of uncomplicated malaria in children in Guinea-Bissau with chloroquine, quinine, and sulfadoxine-pyrimethamine

With the increasing resistance to commonly used antimalarial drugs, different untested 'local' treatment regimens for malaria will arise. We compared commonly used treatment regimens for children in Guinea-Bissau. Symptomatic children with Plasmodium falciparum mono-infection were allocated at random to one of 4 treatments: 15 mg/kg quinine twice a day for 3 d (group 1); 10 mg/kg quinine twice a day for 3 d followed by a total dose of 25 mg chloroquine base given over 3 d (group 2); a total dose of 50 mg/kg chloroquine base given in 2 daily doses for 3 d (group 3), or sulfadoxine-pyrimethamine (group 4). On day 28 more children from group 1 (33%; relative risk [RR] = 2.9, 95% confidence interval [CI] 1.5-5.7) and group 2 (26%; RR = 2.1, CI 1.0-4.3) had had parasitaemia than in group 4 (12%), whereas no significant difference was found between group 3 (17%; RR = 1.3, CI 0.6-2.2) and group 4. No severe adverse reaction was observed in any of the groups. Chloroquine is still effective in Guinea-Bissau at an increased dose of 50 mg/kg, which appears safe when given orally in 2 daily doses for 3 d. Sulfadoxine-pyrimethamine could serve as an efficient, cheap and easy to administer second-line drug, leaving quinine to be used for third-line treatment. Quinine should not be used in short courses, nor does the combination of quinine and chloroquine have any advantage.

Treatment of Plasmodium falciparum malaria with quinine in children in Guinea-Bissau: one daily dose is sufficient

We have earlier obtained good results in falciparum malaria by treating children with low doses of quinine for 7 days in Guinea-Bissau. In order to further simplify treatment, we compared outcome in 100 children with falciparum malaria treated in 1999/2000 for 7 days with 15 mg quinine salt/kg/dose twice daily (group I), 100 children treated with 7.5 mg quinine salt/kg/dose twice daily (group II), and 100 children treated with one single daily dose of 15 mg/kg. One day 28, parasites had reappeared in 12%, 15%, and 9%, respectively. These results are similar to what has been found after previous successful treatment regimens. Apart from a higher incidence of vomiting during the first 24 h of treatment in the groups treated with 15 mg/kg/dose no significant differences in symptoms or side-effects were found between the groups. In patients suffering from uncomplicated malaria, treatment with quinine can be simplified to one single dose of 15 mg/kg bodyweight whenever logistics make 2 daily doses less feasible.