Further evaluation of the NWF filter for the purification of Plasmodium vivax-infected erythrocytes

• Published in: Malaria Journal
• Main Authors: Jiangyan Li, Zhiyong Tao, Qian Li, Awtum Brashear, Ying Wang, Hui Xia, Qiang Fang, Liwang Cui
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2017
• Subjects: Plasmodium vivax; Infected red blood cell; Filter; Purification; Field evaluation; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-017-1855-3; https://doaj.org/article/9233891f19844c35b5a3f46b4c69dd02

Abstract Background Isolation of Plasmodium-infected red blood cells (iRBCs) from clinical blood samples is often required for experiments, such as ex vivo drug assays, in vitro invasion assays and genome sequencing. Current methods for removing white blood cells (WBCs) from malaria-infected blood are time-consuming or costly. A prototype non-woven fabric (NWF) filter was developed for the purification of iRBCs, which showed great efficiency for removing WBCs in a pilot study. Previous work was performed with prototype filters optimized for processing 5–10 mL of blood. With the commercialization of the filters, this study aims to evaluate the efficiency and suitability of the commercial NWF filter for the purification of Plasmodium vivax-infected RBCs in smaller volumes of blood and to compare its performance with that of Plasmodipur® filters. Methods Forty-three clinical P. vivax blood samples taken from symptomatic patients attending malaria clinics at the China–Myanmar border were processed using the NWF filters in a nearby field laboratory. The numbers of WBCs and iRBCs and morphology of P. vivax parasites in the blood samples before and after NWF filtration were compared. The viability of P. vivax parasites after filtration from 27 blood samples was examined by in vitro short-term culture. In addition, the effectiveness of the NWF filter for removing WBCs was compared with that of the Plasmodipur® filter in six P. vivax blood samples. Results Filtration of 1–2 mL of P. vivax-infected blood with the NWF filter removed 99.68% WBCs. The densities of total iRBCs, ring and trophozoite stages before and after filtration were not significantly different (P > 0.05). However, the recovery rates of schizont- and gametocyte-infected RBCs, which were minor parasite stages in the clinical samples, were relatively low. After filtration, the P. vivax parasites did not show apparent morphological changes. Culture of 27 P. vivax-infected blood samples after filtration showed that parasites successfully matured into the ...