RESUMEN
A study was undertaken to investigate the possible involvement of leptospires in causing infection and persistent deaths among albino mice and wistar rats of a laboratory animal house. The serological study revealed that 79.2% of mice, 90% of wistar rats, 71.4% of guinea pigs and 81.8% of rabbits had leptospiral antibodies to one or more of serogroups. Autumnalis predominated in guinea pigs and mice, while Javanica predominated in wistar rats. Rabbits exhibited equal seroprevalence of Autumnalis and Javanica. The animal house workers had 91.0% sero positivity, predominantly Autumnalis while control human group had only 20%. All isolations made from a mice (M2) and six wistar rats (W1, W4, W8 W9, W12 & W13) were serovar javanica and incidentally the isolate from a trapped house rat (R1) also belonged to the same serovar javanica. The house rat was perhaps the source of virulent leptospires for causing infection and mortality among laboratory animals like mice and wistar rats.