[1] VET ADM HOSP, PORTLAND, OR 97207 USA
[2] VET ADM HOSP, ALBUQUERQUE, NM 87108 USA
[3] VET ADM MED CTR, PROVIDENCE, RI USA
[4] GOTENBURG UNIV, INST MED MICROBIOL, S-41124 GOTHENBURG, SWEDEN
[5] COOPERAT STUDIES PROGRAM COORDINATING CTR, W HAVEN, CT USA