Whatman 3 filter paper

Human Whole Blood (K3 EDTA) was purchased from Bioreclamation IVT (Catalog No. HMWBEDTA3). Plasmodium falciparum D6 parasite was cultured in house. Recombinant HRP2 protein (rc-HRP2) for traditional ELISA standard curve was purchased from Immunology Consultants Laboratory Inc. (Catalog No. AGPF-55). ELISA capture and detection antibodies were acquired from Abcam Inc. (Catalog Nos. ab9206 and ab30384). Immulon 2HB ELISA plates (Catalog No. 14-245-61) and TMB One ELISA substrate (Catalog No. PR-G7431) were purchased from Fisher Scientific. 903 Protein Saver cards and Whatman 3 filter paper, were purchased from GE Healthcare Life Sciences (Catalog Nos. 10534612 and 1003-055). Biopunches, 6 mm, were acquired from Ted Pella Inc. (Catalog No. 15111-60). All other reagents were purchased from either Fisher Scientific or Sigma Aldrich. DBS extraction was performed with a Fisher Scientific Analog Vortex Mixer (Catalog No. 02-215-365). Absorbance measurements were collected on a Biotek Synergy H4 microplate reader (Vanderbilt University) or Biotek ELx808 microplate reader (Macha Research Trust).

Two cross-sectional studies were conducted over a two-year period. The first was conducted in November 2017, where 210 children aged between 4 and 13 years were enrolled. The second study was conducted in December 2019 where 164 children aged between three and 13 years were recruited. The study was conducted in Simiw, a community in the KEEA District of the Central Region of Ghana (Figure 1). Recruitment of study participants was done from the Simiw Basic School at both time points. All children aged between 3 and 13 years were illegible to be enrolled into the study.
Approximately 150 μl of finger-pricked blood was obtained from each child. The blood was used to prepare a thick and thin blood film as well spot a strip of Whatman® #3 filter paper (GE Healthcare, USA). The blood films were processed for microscopy, whilst the blood spots were air-dried and stored in a Ziplock® bag containing silica gel beads. The samples were then transported to the NMIMR for onward processing and malaria parasite identification.