passages.id: split_1_test_541_passage
passages.type: progene_text
passages.text: Among the suspected cases ( i.e. those initially found to be parasite - negative but to be antigen - positive ) , trypanosomes were detected in 29 ( 4.2 % ) of those checked at a 3 - month follow - up , and 17 more such suspects when they were followed up at 6 - 18 months .