Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial.

BACKGROUND: Primaquine and methylene blue are gametocytocidal compounds that could prevent Plasmodium falciparum transmission to mosquitoes. We aimed to assess the efficacy and safety of primaquine and methylene blue in preventing human to mosquito transmission of P falciparum among glucose-6-phosphate dehydrogenase (G6PD)-normal, gametocytaemic male participants. METHODS: This was a phase 2, single-blind, randomised controlled trial done at the Clinical Research Centre of the Malaria Research and Training Centre (MRTC) of the University of Bamako (Bamako, Mali). We enrolled male participants aged 5-50 years with asymptomatic P falciparum malaria. G6PD-normal participants with gametocytes detected by blood smear were randomised 1:1:1:1 in block sizes of eight, using a sealed-envelope design, to receive either sulfadoxine-pyrimethamine and amodiaquine, sulfadoxine-pyrimethamine and amodiaquine plus a single dose of 0·25 mg/kg primaquine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus 15 mg/kg per day methylene blue for 3 days. Laboratory staff, investigators, and insectary technicians were masked to the treatment group and gametocyte density of study participants. The study pharmacist and treating physician were not masked. Participants could request unmasking. The primary efficacy endpoint, analysed in all infected patients with at least one infectivity measure before and after treatment, was median within-person percentage change in mosquito infectivity 2 and 7 days after treatment, assessed by membrane feeding. This study is registered with ClinicalTrials.gov, number NCT02831023. FINDINGS: Between June 27, 2016, and Nov 1, 2016, 80 participants were enrolled and assigned to the sulfadoxine-pyrimethamine and amodiaquine (n=20), sulfadoxine-pyrimethamine and amodiaquine plus primaquine (n=20), dihydroartemisinin-piperaquine (n=20), or dihydroartemisinin-piperaquine plus methylene blue (n=20) groups. Among participants infectious at baseline (54 [68%] of 80), those in the sulfadoxine-pyrimethamine and amodiaquine plus primaquine group (n=19) had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with sulfadoxine-pyrimethamine and amodiaquine alone (n=12; -10·2%, IQR -143·9 to 56·6; p<0·0001). The dihydroartemisinin-piperaquine plus methylene blue (n=11) group had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with dihydroartemisinin-piperaquine alone (n=12; -6·0%, IQR -126·1 to 86·9; p<0·0001). Haemoglobin changes were similar between gametocytocidal arms and their respective controls. After exclusion of blue urine, adverse events were similar across all groups (59 [74%] of 80 participants had 162 adverse events overall, 145 [90%] of which were mild). INTERPRETATION: Adding a single dose of 0·25 mg/kg primaquine to sulfadoxine-pyrimethamine and amodiaquine or 3 days of 15 mg/kg per day methylene blue to dihydroartemisinin-piperaquine was highly efficacious for preventing P falciparum transmission. Both primaquine and methylene blue were well tolerated. FUNDING: Bill & Melinda Gates Foundation, European Research Council

Effets de la température sur la germination et la croissance de<em> Cladosporium musae</em> en vue d’une étude des relations hôtes-pathogènes

National audienceCladosporium musae Mason est un champignon associé à Mycosphaerella fijiensis dans la majorité des bananeraies en Côte d’Ivoire. La sévérité des attaques dans les zones de production est fonction des cultivars mais aussi des conditions de développement des maladies. A cause de son association aux cercosporioses, l’étude de la maladie dans les conditions d’inoculations contrôlées nécessite la maîtrise des conditions de température favorable à la réalisation des inoculations in vitro. Une souche du champignon isolée sur le cultivar Figue sucrée et nommée Cl2 dans la mycothèque du laboratoire de Physiologie Végétale a été utilisée en vue d’étudier l’influence de la température sur la croissance des colonies in vitro. Les températures utilisées sont 20°, 25°, 30° et 35 °C et les paramètres utilisés sont les taux de germination, la longueur des filaments germinatifs et la vitesse de croissance des colonies. Les résultats ont montré que la température agit sur la germination des spores et sur la longueur des filaments germinatifs. L’influence de la température est aussi marquée sur la croissance radiale. Cette étude a permis de situer les limites de température dans lesquelles peuvent être conduites en conditions contrôlées in vitro, les études de relations hôtes pathogènes

Effets de la température sur la germination et la croissance de<em> Cladosporium musae</em> en vue d’une étude des relations hôtes-pathogènes

National audienceCladosporium musae Mason est un champignon associé à Mycosphaerella fijiensis dans la majorité des bananeraies en Côte d’Ivoire. La sévérité des attaques dans les zones de production est fonction des cultivars mais aussi des conditions de développement des maladies. A cause de son association aux cercosporioses, l’étude de la maladie dans les conditions d’inoculations contrôlées nécessite la maîtrise des conditions de température favorable à la réalisation des inoculations in vitro. Une souche du champignon isolée sur le cultivar Figue sucrée et nommée Cl2 dans la mycothèque du laboratoire de Physiologie Végétale a été utilisée en vue d’étudier l’influence de la température sur la croissance des colonies in vitro. Les températures utilisées sont 20°, 25°, 30° et 35 °C et les paramètres utilisés sont les taux de germination, la longueur des filaments germinatifs et la vitesse de croissance des colonies. Les résultats ont montré que la température agit sur la germination des spores et sur la longueur des filaments germinatifs. L’influence de la température est aussi marquée sur la croissance radiale. Cette étude a permis de situer les limites de température dans lesquelles peuvent être conduites en conditions contrôlées in vitro, les études de relations hôtes pathogènes

Measuring the impact of seasonal malaria chemoprevention as part of routine malaria control in Kita, Mali

Abstract Background Seasonal malaria chemoprevention (SMC) is a new strategy recommended by WHO in areas of highly seasonal transmission in March 2012. Although randomized controlled trials (RCTs) have shown SMC to be highly effective, evidence and experience from routine implementation of SMC are limited. Methods A non-randomized pragmatic trial with pre-post design was used, with one intervention district (Kita), where four rounds of SMC with sulfadoxine + amodiaquine (SP + AQ) took place in August–November 2014, and one comparison district (Bafoulabe). The primary aims were to evaluate SMC coverage and reductions in prevalence of malaria and anaemia when SMC is delivered through routine programmes using existing community health workers. Children aged 3–59 months from 15 selected localities per district, sampled with probability proportional to size, were surveyed and blood samples collected for malaria blood smears, haemoglobin (Hb) measurement, and molecular markers of drug resistance in two cross-sectional surveys, one before SMC (July 2014) and one after SMC (December 2014). Difference-in-differences regression models were used to assess and compare changes in malaria and anaemia in the intervention and comparison districts. Adherence and tolerability of SMC were assessed by cross-sectional surveys 4–7 days after each SMC round. Coverage of SMC was assessed in the post-SMC survey. Results During round 1, 84% of targeted children received at least the first SMC dose, but coverage declined to 67% by round 4. Across the four treatment rounds, 54% of children received four complete SMC courses. Prevalence of parasitaemia was similar in intervention and comparison districts prior to SMC (23.4 vs 29.5%, p = 0.34) as was the prevalence of malaria illness (2.4 vs 1.9%, p = 0.75). After SMC, parasitaemia prevalence fell to 18% in the intervention district and increased to 46% in the comparison district [difference-in-differences (DD) OR = 0.35; 95% CI 0.20–0.60]. Prevalence of malaria illness fell to a greater degree in the intervention district versus the comparison district (DD OR = 0.20; 95% CI 0.04–0.94) and the same for moderate anaemia (Hb < 8 g/dL) (DD OR = 0.26, 95% CI 0.11–0.65). The frequency of the quintuple mutation (dhfr N51I, C59R and S108N + dhps A437G and K540E) remained low (5%) before and after intervention in both districts. Conclusions Routine implementation of SMC in Mali substantially reduced malaria and anaemia, with reductions of similar magnitude to those seen in previous RCTs. Improving coverage could further strengthen SMC impact. Trial registration clinical trial registration number NCT0289429