Fig. 2.

Flow diagram showing reasons for excluding patients from analysis. 1945 subjects were initially screened for HTLV-1 infection using serological tests. In 56 cases (Group 1, 48; Group 2, 4; Group 3, 4), initial serological screening tests were positive, but subjects were excluded because confirmatory testing could not be performed. In 19 cases confirmatory Western blot tests could not be performed because insufficient sample remained after the initial screening tests. In a further 37 cases, Western blots were indeterminate, but an appropriate sample for HTLV-1 PCR could not be collected because patients had returned to their remote communities before the Western blot result was available to clinicians. Thus, 1889 subjects were included in the final analysis. Abbreviations: HTLV-1+, positive HTLV-1 serological screening test; HTLV-1 WB+, positive HTLV-1 Western blot test; PCR, polymerase chain reaction; WB, Western blot