RT Journal Article SR Electronic T1 Need for vaccination of sewer workers against leptospirosis and hepatitis A JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 71 OP 71 DO 10.1136/oem.53.1.71-c VO 53 IS 1 A1 A G Nicol A1 M E Wright A1 A C Prentice A1 A Carroll A1 S Kemp A1 J M Reed YR 1996 UL http://oem.bmj.com/content/53/1/71.4.abstract AB