Influence of the sickle cell trait on Plasmodium falciparum infectivity from naturally infected gametocyte carriers

Revisiting the determinants of malaria transmission

Malaria parasites have coevolved with humans over thousands of years, mirroring their migration out of Africa. They persist to this day, despite continuous elimination efforts worldwide. These parasites can adapt to changing environments during infection of human and mosquito, and when expanding the geographical range by switching vector species. Recent studies in the human malaria parasite, Plasmodium falciparum, identified determinants governing the plasticity of sexual conversion rates, sex ratio, and vector competence. Here we summarize the latest literature revealing environmental, epigenetic, and genetic determinants of malaria transmission.

Sickle Cell Disease Update: New Treatments and Challenging Nutritional Interventions

Sickle cell disease (SCD), a distinctive and often overlooked illness in the 21st century, is a congenital blood disorder characterized by considerable phenotypic diversity. It comprises a group of disorders, with sickle cell anemia (SCA) being the most prevalent and serious genotype. Although there have been some systematic reviews of global data, worldwide statistics regarding SCD prevalence, morbidity, and mortality remain scarce. In developed countries with a lower number of sickle cell patients, cutting-edge technologies have led to the development of new treatments. However, in developing settings where sickle cell disease (SCD) is more prevalent, medical management, rather than a cure, still relies on the use of hydroxyurea, blood transfusions, and analgesics. This is a disease that affects red blood cells, consequently affecting most organs in diverse manners. We discuss its etiology and the advent of new technologies, but the aim of this study is to understand the various types of nutrition-related studies involving individuals suffering from SCD, particularly in Africa. The interplay of the environment, food, gut microbiota, along with their respective genomes collectively known as the gut microbiome, and host metabolism is responsible for mediating host metabolic phenotypes and modulating gut microbiota. In addition, it serves the purpose of providing essential nutrients. Moreover, it engages in direct interactions with host homeostasis and the immune system, as well as indirect interactions via metabolites. Nutrition interventions and nutritional care are mechanisms for addressing increased nutrient expenditures and are important aspects of supportive management for patients with SCD. Underprivileged areas in Sub-Saharan Africa should be accompanied by efforts to define and promote of the nutritional aspects of SCD. Their importance is key to maintaining well-being and quality of life, especially because new technologies and products remain limited, while the use of native medicinal plant resources is acknowledged.

Biomarker of Anopheles exposure in Ghanaian children with haemoglobin S and C

Heterozygous carriers of haemoglobin S and C (HbAS and HbAC) have a reduced risk of severe malaria but are not protected from Plasmodium falciparum infection, suggesting that the protection involves acquired immunity. During a blood meal, female Anopheles mosquitoes inject saliva that can elicit a host antibody response, which can serve as a proxy for exposure to Plasmodium infection. Previous studies have shown that the peptide gSG6-P1 of An. gambiae saliva is antigenic and highly Anopheles specific. Here, we used plasma samples from 201 Ghanaian children with wild-type haemoglobin (HbAA), HbAS, and HbAC to evaluate antibody levels against gSG6-P1 as a serological biomarker of Anopheles exposure and, therefore of P. falciparum infection risk. Malaria antigen (PfCSP, GLURP, Pfs230, and HB3VAR06)-specific IgG levels, demographic data, and data regarding P. falciparum infection and malaria control practices were also analysed. Children with active P. falciparum infection had higher antibody levels against all antigens, and those with HbAS and HbAC had significantly higher antibody levels against Pfs230. Pfs230-specific IgG correlated negatively with gSG6-P1-specific IgG in children with HbAC. Our results highlight the importance of studying the role of haemoglobinopathies in malaria transmission to improve control interventions.