1Department of Veterinary Pathology, Madras Veterinary College, Chennai - 600 007 (T.N.).
2Leptospirosis Research Laboratory, Centre for Animal Health Studies, Madhavaram Milk Colony, Chennai - 600 051.
3Centralised Clinical Laboratory, Madras Veterinary College, Chennai - 600 007.
4Centre for Animal Health Studies, Madhavaram Milk Colony, Chennai - 600 051.
*Part of the Ph.D. Thesis of the first author permitted for publication by Tamil Nadu Veterinary and Animal Sciences University.