Five species of Plasmodium parasites cause human malaria: P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. Most research and elimination efforts focus on P. falciparum that cause half a million deaths every year, while P. vivax, the most widespread human malaria parasite threatening ~2.5 billion people and causing 72-390 million clinical cases worldwide each year, remains dramatically understudied. In contrast to P. falciparum, P. vivax cannot be continuously propagated in vitro which limits the scope of studies that can be conducted on this important human pathogen and hampers our understanding of its biology. This is especially problematic since findings from P. falciparum can often not be translated to P. vivax due to their important biological differences, that include the existence of a dormant P. vivax stage, the earlier apparition of sexual stages (responsible for transmission), and the lower pyrogenic threshold.
To overcome the difficulty of studying P. vivax in the laboratory, we are applying genomic approaches (including whole genome sequencing, high-throughput genotyping and RNA-seq) to investigate key biological features – such as drug resistance, relapse or gametocytogenesis – using clinical samples and experimental infections in non-human primates.
Vector-borne diseases remain a major public health problem and every year, more than one billion cases and over one million deaths worldwide are caused by pathogens transmitted by arthropods. Vector-borne pathogens also cause a variety of animal diseases and result in important economic losses and, sometimes, zoonoses. Disease surveillance is critical for reducing disease transmission and preventing outbreaks but, unfortunately, is complicated by the resource-intensive nature of entomological surveys.
Our laboratory is developing novel genomic-based approaches to simultaneously characterize, in a high-throughput and cost-efficient manner, the diversity of vector species, their feeding behavior and the pathogens they carry.
High-throughput screening of eukaryotic parasites
Very diverse pathogens can cause infection in humans, including bacteria, viruses and eukaryotic parasites. While genomic tools have revolutionized the study of bacteria, detection of most eukaryotic parasites remain cumbersome and imprecise. Most detection approaches rely on microscopy which, while inexpensive and easy to implement in clinical settings, is low-throughput, and often fails to differentiate among closely related organisms that can have very different pathogenicity. Molecular approaches (including PCR) are specific and sensitive but only test for a handful of specific pathogens and will fail to detect unknown organisms.
Our laboratory is currently optimizing a novel sequencing-based assay to detect and characterize all eukaryotic parasites present in a sample, regardless of whether they have been previously characterized (and may therefore reveal novel pathogens). This assay can complement classical microbiology approaches and be applied to a wide variety of settings including human health, agricultural research, and food and water safety.