THE PREVALENCE AND EPIZOOTIOLOGY OF SALMONELLOSIS AMONG GROUPS OF HORSES IN SOUTH EAST QUEENSLAND

Over a 3-year period, 1178 faecal samples were cultured from 462 horses admitted to the equine clinic of the University of Queensland; 185 samples were positive for salmonella yielding 213 isolations consisting of 21 serotypes. S. anatum was the predominant serotype isolated (54%) followed by S. ohio (11.27%) and S. typhimurium (9.4%). One hundred and ten horses (23.81%) were positive on one or more occasion, and 42 (9.09%) on more than one occasion.
S. anatum was the most common serotype isolated (71.43%) from the main drains in the stable block (33.57% positive samples).
The prevalence of salmonella excretors among a large non-clinic population of horses in south east Queensland was 1.65%.
Acute salmonellosis did not occur in the hospitalised animals. However, salmonellas were incriminated in 6 cases of chronic diarrhoea, which all yielded S. anatum , although the most severe involved both S. anatum and S. typhimurium , and these serotypes were isolated from multiple locations at the subsequent autopsy of 3 cases.