Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2009
Publication Date: 9/21/2009
Citation: Zuerner, R.L., Alt, D.P., Palmer, M.V. 2009. Development of Hamster Models for Acute and Chronic Infections with Leptospira borgpetersenii serovar Hardjo. Meeting Abstract.
Technical Abstract: The Golden Syrian hamster is frequently used as a small animal model to study acute leptospirosis. However, use of this small animal model to study Leptospira borgpetersenii serovar Hardjo infections has not been well documented. Cattle are the normal maintenance hosts of L. borgpetersenii serovar Hardjo and development of a small animal model to study infections with this serovar is important for vaccine development and testing. In this study, we tested the ability of two strains L. borgpetersenii serovar Hardjo to infect hamsters, strain JB197 and strain 203; both strains were originally isolated from cattle and can be used to establish experimental infections in the normal host. Hamsters infected with strain JB197 develop a potentially lethal acute infection in as short a period as 4 days post-incoulation, while infection with strain 203 fails to produce clinical signs of infection. Histopathology and bacterial culture of tissues showed that both strains have similar ability to establish an infection in hamsters (ID50 approximately 150 bacteria). However, strain JB197 is highly virulent (LD50 10**4 bacteria) whereas infection with the highest infectious dose tested (10**9 cells) of strain 203 failed to produce overt clinical signs of infection. Histopathology and immunofluorescence microscopy showed strain JB197 invaded all tissues examined including liver, kidney, pancreas, lung, heart, and intestine. In contrast, strain 203 was found predominantly in kidney and appeared to transiently infect other organs. Thus, in hamsters, strain 203 infections appear to mimic chronic infections typically associated with serovar Hardjo infections in cattle, while infection with strain JB197 resembles accidental infections of non-maintenance hosts. Use of these two strains in the hamster model should aid development of effective vaccines suitable for both maintenance and accidental hosts.