The MalariaWorld Journal

 

We tested in vivo effects of L-buthionine (S,R)-sulfoximine (BSO) on glutathione (GSH) and hemozoin formation in arteether-sensitive and - resistant strains of Plasmodium vinckei. Groups of 7-8 Swiss mice were inoculated by intraperitoneal injection (i.p.) with 1×10⁶ parasitized erythrocytes of PvAS (sensitive) or PvAR (resistant) strain of P. vinckei. The infected mice were treated with BSO (Sigma) 400 mg/kg twice a day for four days and blood was collected after the last injection with BSO. A relatively stronger inhibition of GSH level was observed in the blood of mice infected with resistant parasites (62.64%; p<0.0001), whereas inhibition in sensitive strain-infected mice and uninfected mice was 32% (p=0.034) and 35% (p=0.034), respectively. The results also show an inverse relationship between GSH and hemozoin in the arteether-sensitive and -resistant strains. The hemozoin contents in the resistant strain are 0.27±0.09, 0.69±0.14 and 5.30±0.79 μmol/10⁹ cells at 5, 10 and 20% parasitemia, respectively, whereas hemozoin contents in the sensitive strain at the same parasitemia levels are 0.59±0.29, 12.38±1.96 and 30.80±2.27 μmol/10⁹ cells. Moreover, hemozoin formation increased by 80% through the administration of BSO in the arteether-resistant strain, whereas insignificant changes occurred in the sensitive strain. BSO was also found to increase the efficacy of arteether antimalarial activity against the resistant strain in vivo. It is concluded that treatment with BSO significantly reduces the level of GSH, which leads to insufficient growth of resistant parasites. These results suggest that BSO might be helpful in prolonging the persistence of the drug, and pose a promising lead to help reducing the chance of resistance development against artemisinin and its derivatives.

 

 

A malaria vaccine is a potentially effective addition to the armamentarium for malaria control. The candidate RTS,S malaria vaccine has undergone phase III clinical trials and WHO has indicated that a policy recommendation is possible in 2015. Given the delays with adoption of other novel interventions including vaccines, there is a need to ensure that all elements that will inform the decision to adopt a malaria vaccine, including community willingness, will be available on time. This study was carried out to assess the willingness of caregivers of under-5 children to accept a malaria vaccine once available and recommended for use. 427 consenting caregivers, selected using a cluster sampling technique, from five communities in Ibadan, Nigeria, participated in a questionnaire. In-depth interviews (IDIs) were conducted among 47 key community members. Data were analysed using descriptive statistics, Chi-square and logistic regression at p≤0.05. Thematic content analysis was used to analyse the transcribed IDI data. The mean age of survey respondents was 29.8±5.8 years. Only 20.1% of the respondents had ever heard of malaria vaccine; 87.0% showed willingness to accept a malaria vaccine. Reasons stated for not willing included ‘husband did not want immunisation’ (73.6%), ‘felt it might be expensive’ (47.2%) and ‘felt it might paralyse children’ (24.5%). Nearly half (48.7%) of the respondents said that if vaccine is not given orally like polio vaccine it might not be accepted. Influence of community health workers was found to predict willingness to accept a malaria vaccine (OR: 0.316, 95% CI: 0.142-0.705). IDI participants were favourably disposed to introduction of a vaccine against malaria, although they had concerns about the formulation of the vaccine and possible adverse events. Well-designed communication strategies implemented prior to the introduction of a malaria vaccine would be essential to foster a supportive environment for eventual adoption and acceptance thereof. 

This study aimed at determining the performances of the Optimal-IT® test in the strategy for the exclusive treatment of uncomplicated malaria in rural areas in the forest region of San Pedro, Côte d’Ivoire. Patients exhibiting clinical signs of uncomplicated malaria who gave their consent benefited from thick blood film (TBF), blood smear (BS) and Optimal-IT® (pLDH-based) tests. Rapid diagnostic test (RDT) results were taken into consideration to decide on malaria treatment and then compared with TBF/BS results (reference) to assess the performances and clinical usefulness of the RDT. TBF/BS and Optimal-IT® were concordant in 92% of patients but discordant in 10 false negative (3%) and 19 false- positive patients (5%). The performances calculated were: sensitivity=95%, specificity=91%, positive predictive value=90%, negative predictive value=95%, positive likelihood ratio=10, negative likelihood ratio=0.06 and diagnostic odds ratio=166, indicating that Optimal-IT® is a powerful and credible diagnostic tool. The Optimal-IT® test, which is already used in the field, showed good performances to effectively detect patients with and without malaria. It is therefore adapted to the malaria treatment strategy limited to confirmed cases.