Artificial intelligence-supported digital microscopy for rapid malaria diagnosis
Hans-Peter Beck (Basel | CH)
Besides the very frequent use of rapid diagnostic tests (RDTs) for malaria diagnosis in the field, expert microscopy is still used for reliable diagnosis. In contrast to microscopy, RDTs are unable to quantify parasitemia, identify gametocytes, and cannot distinguish all malaria species. Furthermore, the rapid spread of Plasmodium parasites having the hrp2/hrp3 gene deleted compromises the reliable use of RDTs. Here we present an innovative platform that is designed to be employed in endemic areas that automatically generates microscopic blood smears termed miLab. These smears are liquid-free stained using a hydrogel-based stamping technology coupled with automatic digital microscopy. Images are captured digitally and analysed by a machine-learning algorithm that results in parasite quantification, parasite speciation and gametocytes identification. Here we report the instrument validation with full human blood samples spiked with various numbers of synchronized and non-synchronized cultured P. falciparum parasites. In addition, we have used cultures and induced gametocytes for training the algorithm to also detect gametocytes. The platform has also been employed in a clinical field study and first results will be reported.
Detection of Dicistroviruses RNA in Blood of Febrile Tanzanian Children
Samuel Cordey (Genève | CH)
Background & Objectives
Fever is the leading cause of paediatric outpatient consultations in Sub-Saharan Africa. Although most are suspected to be of viral origin, a putative causative pathogen is not identified in over a quarter of these febrile episodes.
Material and method
This study includes sera from 692 febrile children (aged 2-59 months) and plasma from 77 febrile adults recruited at outpatient clinics in Tanzania. These blood products were analysed by high-throughput sequencing for novel viruses using a de novo assembly approach.
We report the presence of RNA from a dicistrovirus (DicV) in 15.4% of the paediatric cohort. In contrast, DicV RNA was only detected in 1/77 (1.3%) plasma samples from febrile Tanzanian adults, suggesting that children could represent the primary susceptible population. The virus is novel to human tissue and phylogenetic analysis of the capsid region in the three full-length genomes obtained showed the presence of two clusters representing a tentative novel genus. Estimated viral load across all samples by specific quantitative real-time RT-PCR assay ranged from < 1.32E3 to 1.44E7 viral RNA copies/mL serum (median = 5.67E3). Although DicV-positive cases were detected throughout the year, a significantly higher positivity rate was observed during the rainy season. A comparative analysis between DicV-positive and negative patients did not reveal any significant clinical differences, except that DicV-positive patients had a lower mean age (16.4 vs 18.9 months, p = 0.02).
Dicistrovirus is part of a family of RNA viruses that have been detected in some hematophagous insects that are known vectors of parasitic disease in humans (such as triatomes). This study reveals that novel DicV RNA is frequently detected in the blood of Tanzanian children and works to encourage further investigations to determine whether DicV may be a novel infectious agent in humans.