A long period of clinical latency before development of symptoms is characteristic of human immunodeficiency virus type 1 ( HIV-1 ) infection .
a long period of clinical latency before development of symptoms is characteristic of human immunodeficiency virus type 1 ( hiv-1 ) infection .
O O O O O O O O O O O O O B-virus I-virus I-virus I-virus I-virus O B-virus O O O