The criteria for a positive IFAT result were established in a previous experiment. Briefly, when 86 individuals and 58 vivax malaria patients were tested, normal individuals had a serum dilution under 1:16 (range from 0 to 1:16), and the 58 vivax malaria patients had a serum dilution over 1:256 (range from 1:256 to 1:4,096). Therefore, a positive antibody response was defined against vivax malaria as a serum dilution above (≥)1:32. The specificity of IFAT was 100% and sensitivity was 97% [
20]. A total of 114 samples from 1,574 participants (7.24%) that were identified as negative by microscopic examination were positive by IFAT. A total 17 positive samples exhibited IFAT scores of ≥1:256, which was the criterion used to identify malaria patients. Gimpo had the highest positive rate at 13.68% (52/380) followed by Cheorwon (7.01%, 27/385), Paju (5.51%, 26/472), Yeoncheon (3.32%, 7/211), and Goseong (1.59%, 2/126) (Additional file
1). Tongjin village, located in the upper-middle area of Gimpo, had the highest positive rate at 17.65% (9/51) followed by Wolgot village (14.63%, 24/164) in the north-west part of the city, and Haseong village (11.52%, 19/165) in the north-east (Additional file
2, Figure
1A). Gunnae village, located adjacent to the DMZ in Paju, had the highest positive rate of 8.89% (8/90) followed by Munsan village (7.26%, 13/179) in the upper-middle of the city, and Tanhyun village (2.46%, 5/203) in the north-west (Additional file
3, Figure
1B). Cheongsan village, located far south of Yeoncheon, had the highest positive rate at 5.41% (2/37) followed by Yeoncheon village (2.87%, 5/174) located in the middle of Yeoncheon (Additional file
4, Figure
1C). Galmal village, located in the south-west of Cheorwon, had the highest positive rate at 11.48% (7/61) followed by Seo village (9.52%, 4/42) in the south-east of the city, Geunnam village (9.09%, 5/55) and Gimhwa village (6.67%, 2/30) in the north-east, and Dongsong village (4.57%, 9/197) in the west of the city (Additional file
5, Figure
1D). Hyeonnae village, located in the north part of Goseong, had a positive rate of 1.59% (2/126) (Additional file
6, Figure
1E).