Tolérance et efficacité de l’atovaquone-proguanil dans le traitement du paludisme d’importation à Plasmodium falciparum de l’enfant en France métropolitaine : expérience d’un centre hospitalier parisien

Clinical implications of Plasmodium resistance to atovaquone/proguanil: a systematic review and meta-analysis

Background

Atovaquone/proguanil, registered as Malarone^®, is a fixed-dose combination recommended for first-line treatment of uncomplicated Plasmodium falciparum malaria in non-endemic countries and its prevention in travellers. Mutations in the cytochrome bc₁ complex are causally associated with atovaquone resistance.

Methods

This systematic review assesses the clinical efficacy of atovaquone/proguanil treatment of uncomplicated malaria and examines the extent to which codon 268 mutation in cytochrome b influences treatment failure and recrudescence based on published information.

Results

Data suggest that atovaquone/proguanil treatment efficacy is 89%–98% for P. falciparum malaria (from 27 studies including between 18 and 253 patients in each case) and 20%–26% for Plasmodium vivax malaria (from 1 study including 25 patients). The in vitro P. falciparum phenotype of atovaquone resistance is an IC₅₀ value >28 nM. Case report analyses predict that recrudescence in a patient presenting with parasites carrying cytochrome b codon 268 mutation will occur on average at day 29 (95% CI: 22, 35), 19 (95% CI: 7, 30) days longer than if the mutation is absent.

Conclusions

Evidence suggests atovaquone/proguanil treatment for P. falciparum malaria is effective. Late treatment failure is likely to be associated with a codon 268 mutation in cytochrome b, though recent evidence from animal models suggests these mutations may not spread within the population. However, early treatment failure is likely to arise through alternative mechanisms, requiring further investigation.

Management and prevention of imported malaria in children. Update of the French guidelines

Since the 2007 French guidelines on imported Falciparum malaria, the epidemiology, treatment, and prevention of malaria have changed considerably requiring guidelines for all Plasmodium species to be updated. Over the past decade, the incidence of imported malaria has decreased in all age groups, reflecting the decrease in the incidence of malaria in endemic areas. The rates of severe pediatric cases have increased as in adults, but fatalities are rare. The parasitological diagnosis requires a thick blood smear (or a rapid immunochromatographic test) and a thin blood film. Alternatively, a rapid antigen detection test can be paired with a thin blood film. Thrombocytopenia in children presenting with fever is highly predictive of malaria following travel to a malaria-endemic area and, when detected, malaria should be strongly considered. The first-line treatment of uncomplicated P. falciparum malaria is now an artemisinin-based combination therapy (ACT), either artemether-lumefantrine or artenimol-piperaquine, as recommended by the World Health Organization in endemic areas. Uncomplicated presentations of non-falciparum malaria should be treated either with chloroquine or ACT. The first-line treatment of severe malaria is now intravenous artesunate which is more effective than quinine in endemic areas. Quinine is restricted to cases where artesunate is contraindicated or unavailable. Prevention of malaria in pediatric travelers consists of nocturnal personal protection against mosquitoes (especially insecticide-treated nets) combined with chemoprophylaxis according to the risk level.

Efficacy and safety of atovaquone-proguanil in treating imported malaria in Japan: the second report from the research group

Malaria remains an important health risk among travelers to tropical/subtropical regions. However, in Japan, only 2 antimalarials are licensed for clinical use - oral quinine and mefloquine. The Research Group on Chemotherapy of Tropical Diseases introduced atovaquone-proguanil in 1999, and reported on its excellent antimalarial efficacy and safety for treating non-immune patients with uncomplicated Plasmodium falciparum malaria (20 adult and 3 pediatric cases) in 2006. In the present study, additional cases of malaria were analyzed to confirm the efficacy and safety of this antimalarial drug. Fourteen adult and 2 pediatric cases of P. falciparum malaria and 13 adult cases and 1 pediatric case of P. vivax/ovale malaria were successfully treated with atovaquone-proguanil, including 3 P. falciparum cases in which the antecedent treatment failed. Two patients with P. vivax malaria were treated twice due to primaquine treatment failure as opposed to atovaquone-proguanil treatment failure. Except for 1 patient with P. falciparum malaria who developed a moderate liver function disturbance, no significant adverse effects were observed. Despite the intrinsic limitations of this study, which was not a formal clinical trial, the data showed that atovaquone-proguanil was an effective and well-tolerated therapeutic option; licensure of this drug in Japan could greatly contribute to individually appropriate treatment options.

[Evaluation of pre-travel prevention, except vaccination, in children returning from Africa with fever]

OBJECTIVES

Evaluating the frequency and modalities of transmissible infection prevention counseling in children before a stay in tropical or subtropical areas.

METHODS

Description of the frequency and modalities of transmissible infection prevention counseling (except specific vaccination) given prior to travel in children attending a tertiary care center in Paris, France, for fever occurring within 3 months following a return from Africa. Data were collected retrospectively from medical observations and telephone interviews with parents.

RESULTS

A total of 173 children were included; 98 and 75 returned from sub-Saharan Africa and North Africa, respectively. Forty-one percent were less than 2 years old. Eighty-one percent of the children had consulted before leaving. Among children who returned from North Africa, the proportion of children who had a specific preventive consultation before travel was lower than among children who returned from sub-Saharan Africa (respectively, 72.1% versus 94.7%; p<0.001). In children having consulted before traveling, specific hygiene and diet advice had been given in 72% of cases but less frequently in children who traveled in North Africa compared to children who traveled to sub-Saharan Africa (respectively, 57.8% vs. 92.2%; p<0.001). Among children who returned from North Africa, those who had no preventive consultation before travel had febrile gastrointestinal infection more frequently than those who had a consultation before traveling (p=0.003).

CONCLUSION

Although in this study the majority of children traveling to Africa receive transmissible infection prevention counseling before the travel, prevention could be improved, particularly before a stay in North Africa.

Mefloquine for uncomplicated Plasmodium falciparum malaria in children

BACKGROUND

Children with uncomplicated Plasmodium falciparum imported malaria are treated with various antimalarial regimens including mefloquine depending on national guidelines. Little is known regarding mefloquine treatment efficacy in this setting.

METHODS

In this prospective study, children 3 months to 16 years of age admitted in a tertiary hospital emergency ward in France with uncomplicated P. falciparum malaria were treated with oral mefloquine. Each dose was given with an antiemetic.

RESULTS

Between 2004 and 2009, 95 children were evaluated. In all, 94% had traveled in the Indian Ocean region (Comoros and Madagascar); 79% used a malaria chemoprophylaxis, but none was fully compliant with World Health Organization recommended regimens. Main clinical features at admission were fever (91%), vomiting (44%), and headaches (44%). Hemoglobin < 80 g/L and platelets <100 G/L were observed in 16% and 17%, respectively. All children were initially cured by mefloquine, and no relapse was noted within 45 days after admission. One Plasmodium vivax relapse occurred 6 months later. Vomiting within 1 hour after dosing occurred in 20% of children. Significant features associated with early vomiting by univariate analysis were a weight ≤ 15 kg, C-reactive protein ≥ 50 mg/L, and parasitemia ≥ 1%, but only low weight was significant by multivariate analysis.

CONCLUSION

Mefloquine is an effective treatment for uncomplicated imported P. falciparum malaria in children returning from countries with low mefloquine resistance. Early vomiting after mefloquine dosing is frequent, especially in children < 15 kg of weight, but a second dose can be given successfully.