No abstract

Kidneys of cattle, mice and badgers were cultured for leptospires in an attempt to evaluate the relative importance of these species in the epidemiology of bovine leptospirosis caused by the Hebdomadis serogroup. Leptospires closely related to serotype hardjo were recovered from 57 (28.5 per cent) of 200 cattle examined but no evidence of infection was found in either badgers or mice, indicating that cattle act as the maintenance host for serotype hardjo. Many cattle were seronegative carriers.

No abstract

During an investigation of pig abortions and stillbirths in Northern Ireland, leptospires were isolated from 55 of the 78 litters examined. Strains belonging to four serogroups (Australis, Icterohaemorrhagiae, Hebdomadis and Autumnalis) were recovered but leptospires of the Australis serogroup accounted for 91 per cent of the isolates. Two serovars of the Australis group bratislava and muenchen, were identified.

The excretion of Leptospira interrogans serovar hardjo in the urine of cattle was studied in naturally and experimentally infected animals. Five of 15 naturally infected animals with microscopic agglutination test titres of > or = 1:300 shed leptospires for between 28 and 40 weeks. Twenty yearling heifers, experimentally infected by either the supraconjunctival or intrauterine routes, shed leptospires for from eight to 60 weeks; the 10 infected via the uterus shed L interrogans serovar hardjo for a mean of 26 weeks (range eight to 54 weeks) and the 10 infected by the supraconjunctival route shed the organism for a mean of 32 weeks (range 12 to 60 weeks). The results suggest that natural infection results in more prolonged excretion than experimental infection. No intermittent or seasonal excretion of the organism was observed. After the initial experimental infection, large numbers of leptospires were shed in the urine for several weeks, and thereafter there was a progressive decline in the number of organisms shed.