Highly Sensitive and Rapid Quantitative Detection of <i>Plasmodium falciparum</i> Using an Image Cytometer

• Main Authors: Muneaki Hashimoto, Kazumichi Yokota, Kazuaki Kajimoto, Musashi Matsumoto, Atsuro Tatsumi, Yoshihiro Nakajima, Toshihiro Mita, Noboru Minakawa, Hiroaki Oka, Masatoshi Kataoka
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Microorganisms
• Subjects: malaria; diagnosis; image cytometer; parasitemia
• Online Access: https://www.mdpi.com/2076-2607/8/11/1769

The gold standard for malaria diagnosis is microscopic examination of blood films by expert microscopists. It is important to detect submicroscopic and asymptomatic <i>Plasmodium</i> infections in people, therefore the development of highly sensitive devices for diagnosing malaria is required. In the present study, we investigated whether an imaging cytometer was useful for the highly sensitive quantitative detection of parasites. Whole blood samples were prepared from uninfected individuals spiked with <i>Plasmodium falciparum</i>-infected erythrocytes. Thereafter, erythrocytes were purified using a push column comprising of a syringe filter unit with SiO₂-nanofiber filters. After adding the erythrocytes, stained with nuclear stain, to a six-well plate, quantitative detection of the parasites was performed using an image cytometer, CQ1. Imaging of 2.6 × 10⁶ erythrocytes was completed in 3 min, and the limit of detection indicated parasitemia of 0.00010% (≈5 parasites/μL of blood). In addition to rapid, highly sensitive, and quantitative detection, the ease of application and economic costs, image cytometry could be efficiently applied to diagnose submicroscopic parasites in infected people from endemic countries.