Whatman fta classic card

One hundred participants were assessed for infection with S. mansoni. Serum samples were obtained after centrifugation of coagulated blood samples at 1200×g for 5 min. The supernatant was centrifuged for a further 15 min at 3000×g. Both centrifugation steps were performed at ambient temperature. The resulting supernatant was pipetted into 2 ml tubes and stored and transported in special thermal packaging at − 20 °C. Dried blood spots were prepared by dropping 125 µl ethylenediaminetetraacetic acid (EDTA)-anticoagulated whole blood onto Whatman™ FTA™ Classic Cards (GE Healthcare Life Sciences, Piscataway, NJ, USA). Cards were dried away from direct sunlight, placed into individual zip bags with desiccant three hours after preparation, and stored at room temperature until processing [34 (link), 35 ].

Data were collected through a cross-sectional, community-based survey. The survey consisted of interviews, blood examinations, and body temperature measurements. All of the villagers in each study village were invited to assemble at a designated place, including a primary school and village health volunteers’ houses. First, trained surveyors, who were nurses or medical technologists, identified a participant by his/her name, the name of his/her household head, and the household ID used for the HDSS. Second, surveyors conducted an interview using a pre-tested questionnaire. In the case of child participants, a guardian responded to the interview. Third, the surveyors measured the body temperature of the participants with a digital ear thermometer (MC-510, Omron Healthcare Co., Ltd., Kyoto, Japan). Finally, the surveyors collected a finger-prick blood sample from the participants that was subjected to RDT (SD Bioline Malaria Ag Pf/Pv, Standard Diagnostics, Inc., Gyeonggi-do, Republic of Korea). Blood samples were also collected for microscopic examination and PCR. For PCR, blood samples were collected on Whatman FTA Classic Cards (GE Healthcare Life Science, Little Chalfont, UK).

Each participant provided a blood sample (9ml), which was collected in an EDTA tube for DNA extraction, when attending the baseline GS:SFHS clinical appointment. This sample was stored at -20°C for between 33 and 497 days. At this point, 100μl of the sample (approximately equivalent to two drops of blood) was blotted onto a Whatman FTA
^® classic card (GE Healthcare; cat. no. WB120205) and DNA was extracted from the remaining sample using the Nucleon BACC3 Genomic DNA Extraction Kit (GE Healthcare; cat. no. RPN8512)
^{18 (link)}, following the manufacturer’s instructions. The Whatman FTA
^® cards were stored at room temperature for between 5 and 10 years until DNA extraction for this project. DNA was extracted from the entire blood spot using the QIAamp DNA Investigator Kit (Qiagen; cat. no. 56504), following the manufacturer’s instructions. The concentration of the DNA samples was measured using a Qubit 2.0 fluorometer and the Qubit dsDNA HS assay (Thermo Fisher; cat. no. Q32854). Sample storage, DNA extraction and DNA quantification took place at the
Edinburgh Clinical Research Facility at the University of Edinburgh.

From each animal, blood was drawn into three capillary tubes (Kimble Chase Life Science, Vineland, NJ, USA) containing heparin (anticoagulant) after puncturing the ear vein of the animal with a blood lancet. One capillary tube was sealed with a crista seal for an on-site examination by buffy coat technique. About 50 µL of blood from the second capillary tube was used to make thin and thick smears for a later microscopic examination at the laboratory [5 (link)]. About 50 µL of blood from the third capillary tube was applied onto a well-labeled Whatman FTA Classic Card (GE Healthcare, Madison, WI, USA) and on Whatman^® No. 1 filter paper (GE Healthcare). After air drying, both the filter paper and FTA card samples were separately packed in zip locked storage bags containing silica gel and transported to the laboratory for further processing with ITS-PCR [18 (link)].