Vaccines directed against the blood stages of Plasmodium falciparum malaria are intended to prevent the parasite from invading and replicating within host cells. No blood-stage malaria vaccine has shown clinical efficacy in humans. Most malaria vaccine antigens are parasite surface proteins that have evolved extensive genetic diversity, and this diversity could allow malaria parasites to escape vaccine-induced immunity. We examined the extent and within-host dynamics of genetic diversity in the blood-stage malaria vaccine antigen apical membrane antigen–1 in a longitudinal study in Mali.
In vitro studies identified a plasmepsin inhibitor that could aid in the development of new treatments for malaria. Further details on the research, next steps and licensing status are discussed in the article.
A vaccine to reduce human suffering caused by malarial parasites has been the holy grail of malaria research. Early studies in the 1940’s indicated that attenuated parasites could induce useful immunity. Since that time the genomic revolution led inevitably to the idea of cheap production of safe recombinant vaccines using either expressed protein or DNA vector technologies.
Single oral doses of artesunate, dihydroartemisinin, arteether and artemether administered to rats during a sensitive period of organogenesis caused embryo deaths and malformations (malformed long bones and ventricular septal defects). Extended oral dosing (12 days or more) of monkeys once daily with 12 mg/kg-d artesunate also caused embryo deaths. The initial embryotoxic effect in both species was to kill primitive erythroblasts which are present in the embryo for a few days of gestation in rats and several weeks in primates.
The quest for an effective vaccine as an additional strategy in the control of malaria and to significantly impact the disease burden has progressed tremendously over the past decade and there is a very high probability that that a malaria vaccine will be available for use in the near future. The introduction of any malaria vaccine will be confronted by some cultural issues and it is essential to understand how these factors will ultimately affect its utilization. These and other challenges related to the development and deployment of an effective malaria vaccine especially as they concern endemic countries are discussed.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a X-chromosomally transmitted disorder of the erythrocyte that affects 400 million people worldwide. Diagnosis of heterozygously-deficient women is complicated: as a result of lyonization, these women have a normal and a G6PD-deficient population of erythrocytes. The cytochemical assay is the only reliable assay to discriminate between heterozygously-deficient women and non-deficient women or homozygously-deficient women. G6PD deficiency is mainly found in areas where malaria is or has been endemic.
Our objective was to assess whether it could be contemplated to recommend Quassia amara young leaf tea for treatment against malaria, and if yes, set up a standard protocol for preparing the herbal tea. In conclusion, this preparation should not be recommended for treatment of malaria until a clinical study in humans is performed with SkD.
The RTS,S/AS01E malaria vaccine candidate has recently entered phase 3 testing. Reaching this important milestone is the culmination of more than 20 years of research and development by GlaxoSmithKline and partners and collaborators. The vaccine has been developed to protect young children and infants living in sub-Saharan Africa against clinical and severe disease caused by Plasmodium falciparum infection.
Plasmodium chabaudi AS infection during early pregnancy results in midgestational embryonic loss in naive C57BL/6 mice. To define the immunopathogenesis of this malaria-induced pregnancy compromise, cytokine production in plasma, spleen, and placenta cell culture supernatants during the first 11 days of infection and gestation was studied. These results suggest that systemic and placenta-level proinflammatory antimalarial immune responses, in the absence of adequate and sustained counterregulatory mechanisms, contribute to pregnancy loss in this model.
The increasing P. vivax drug resistance and reports of severe and lethal cases, the relapsing parasite behavior and the existence of Plasmodium spp co-infections must prompt more investment and greater efforts for the development of P. vivax vaccine.