Differential gene expression in Anopheles stephensi following infection with drug-resistant Plasmodium yoelii

Genomic advances in the study of the mosquito vector during avian malaria infection

Invertebrate host–parasite associations are one of the keystones in order to understand vector-borne diseases. The study of these specific interactions provides information not only about how the vector is affected by the parasite at the gene-expression level, but might also reveal mosquito strategies for blocking the transmission of the parasites. A very well-known vector for human malaria is Anopheles gambiae. This mosquito species has been the main focus for genomics studies determining essential key genes and pathways over the course of a malaria infection. However, to-date there is an important knowledge gap concerning other non-mammophilic mosquito species, for example some species from the Culex genera which may transmit avian malaria but also zoonotic pathogens such as West Nile virus. From an evolutionary perspective, these 2 mosquito genera diverged 170 million years ago, hence allowing studies in both species determining evolutionary conserved genes essential during malaria infections, which in turn might help to find key genes for blocking malaria cycle inside the mosquito. Here, we extensively review the current knowledge on key genes and pathways expressed in Anopheles over the course of malaria infections and highlight the importance of conducting genomic investigations for detecting pathways in Culex mosquitoes linked to infection of avian malaria. By pooling this information, we underline the need to increase genomic studies in mosquito–parasite associations, such as the one in Culex–Plasmodium, that can provide a better understanding of the infection dynamics in wildlife and reduce the negative impact on ecosystems.

Sand Fly Studies Predict Transmission Potential of Drug-resistant Leishmania

Leishmania parasites have the capacity to rapidly adapt to changing environments in their digenetic life cycle which alternates between a vertebrate and an invertebrate host. Emergence of resistance following drug exposure can evoke phenotypic alterations that affect several aspects of parasite fitness in both hosts. Current studies of the impact of resistance are mostly limited to interactions with the mammalian host and characterization of in vitro parasite growth and differentiation. Development in the vector and transmission capacity have been largely ignored. This review reflects on the impact of drug resistance on its spreading potential with specific focus on the use of the sand fly infection model to evaluate parasite development in the vector and the ensuing transmission potential of drug-resistant phenotypes.

The Challenge of Developing a Single-Dose Treatment for Scabies

Scabies is a common skin disease with an estimated worldwide incidence of 200 million people infected per year. Its morbidity and mortality is principally due to secondary bacterial infections, a link now well recognized and prompting the recent inclusion of this disease-complex in the WHO list of neglected tropical diseases. The few treatments available are poorly effective against Sarcoptes scabiei eggs and appear to induce resistance in the parasite. An ideal alternative would be a single-dose regimen that kills all developmental stages, including eggs. Drugs used in the veterinary field and applied to other arthropods could be tested experimentally in an established pig-scabies model. Moreover, functional genomics combined with target validation through biochemical research should assist in identifying new drugs.

Systems Biology-Based Investigation of Host-Plasmodium Interactions

Malaria is a serious, complex disease caused by parasites of the genus Plasmodium. Plasmodium parasites affect multiple tissues as they evade immune responses, replicate, sexually reproduce, and transmit between vertebrate and invertebrate hosts. The explosion of omics technologies has enabled large-scale collection of Plasmodium infection data, revealing systems-scale patterns, mechanisms of pathogenesis, and the ways that host and pathogen affect each other. Here, we provide an overview of recent efforts using systems biology approaches to study host-Plasmodium interactions and the biological themes that have emerged from these efforts. We discuss some of the challenges in using systems biology for this goal, key research efforts needed to address those issues, and promising future malaria applications of systems biology.