Interestingly, anemia (78.91 % Hypochromic RBCs; 232/294) and relative eosinophilia (61.90%; 182/294) have been found in thin blood films of these foreign workers. Specifically, 116 (116/292, 39.45%) workers showed hypochromic normocytic RBC, of which 42 were from Samut Sakhon (42/120, 35.00%) and 74 (74/174, 42.53%) were from Bangkok. 113 (113/174, 64.94%) and workers from Bangkok 69(69/120, 57.50%) from Samut Sakhon showed relative eosinophilia.