Haematology, clinical biochemistry and Salmonella infection in Australian reptiles

© 2011 T. Franciscus ScheelingsThirty-three wild Victorian lace monitors, (Varanus varius), of unknown age and sex, were captured by noose pole or aluminium box trap from Cape Conran in East Gippsland, Victoria, Australia. In addition to establishing reference ranges for blood parameters, it was further examined whether such values were influenced by the expected differences in habitat food resource availability and by body size and body condition. The packed cell volume (PCV) for the lace monitors was 21-43.6%. Lymphocytes were the most common leukocyte. The haemoparasite Hepatozoon varanicola was found in all 33 blood samples. There was a significant difference in the serum glucose concentrations between the two methods of capture (higher concentration in box-trapped animals) presumably due to a physiological response to capture stress. The results of this study may be used as a basis for evaluation of health in lace monitors. Between January 2007 and June 2008 a total of 504 reptiles comprising four families and 57 species were sampled for the presence of Salmonella by cloacal or intestinal swabbing. Salmonella was identified in 139 (27.6%) of the 504 animals tested. Of the 504 reptiles examined, 210 were captive animals and 294 were wild specimens. Ninety-eight (46.8%) of the captive reptiles were found to be shedding Salmonella at the time of sampling. In contrast, only 41 (13.9%) of the wild reptiles were Salmonella positive. The prevalence of Salmonella was significantly higher in captive reptiles (P < 0.0001). Salmonella were not cultured from any of 60 wild freshwater chelonians or 48 wild southern water skinks (Eulamprus heatwolei). In general, snakes had the highest prevalence of Salmonella carriage with 72/104 (69.2%) animals shedding, lizards had an intermediate prevalence, with 65/299 (27.1%) individuals shedding and chelonians had the lowest prevalence with 2/101 (2%) animals shedding. It was also discovered that animals from Healesville Sanctuary were significantly more likely to be shedding Salmonella than reptiles from private collections (P = 0.001) and that Healesville Sanctuary reptile house animals were much more likely to shed Salmonella than animals that reside elsewhere in the park (P < 0.0001). Salmonella enterica subsp. enterica was more frequently identified in wild reptiles than captive reptiles (P = 0.033) and Salmonella enterica subsp. diarizonae was more frequently identified in captive reptiles than wild reptiles (P = 0.001). The results of this investigation suggest that wild reptiles in Australia are much less frequently carriers of Salmonella than captive reptiles and that diet and captivity may influence Salmonella excretion