CULTURAL AND SEROLOGIC EVIDENCE OF Leptospira interrogans SEROTYPE Tarassovi INFECTION IN TURTLES

Abstract

Forty-two of 46 sera (91%) from turtles (Pseudenzys scripta-elegans) in Georgia had microscopic agglutination titers of 200 or greater to Leptospira serotype tarassovi. Leptospires were isolated from eight of ten hamsters (80%) inoculated with surface water collected from the settling ponds of the untreated sewage disposal system in which the turtles lived. Leptospires were also isolated from 12 of 20 hamsters (60%) inoculated with turtle kidney suspensions and six of 20 hamsters (30%) inoculated with turtle cloacal suspension. Hamster brain appeared to be the best tissue for recovering leptospires since 24 of the 41 isolates (59%) from the 26 culture-positive hamsters were from the brain and 17 (41%) were from the kidney. Six of the 41 isolates from hamsters that had been injected with surface water and turtle kidney and cloacal tissue were identified as being identical to serotype tarassovi.

Serum antileptospiral agglutinins in freshwater turtles from Southern Brazil

“…All these cases were associated with T. dorbigny . The second serogroup with more frequent reactions was Tarassovi (27.2%, n=3), an interesting finding since it was the only one serovar isolated from turtles until now (7). On the other hand, only one reactive sample (9.1%) was found for serogroup Icterohaemorrhagiae (serovar Copenhageni) (Table 1), which is mainly carried by rats and is the major cause of severe human leptospirosis in urban areas of Brazil (10).…”

“…The role of reptiles and other poikilothermic vertebrates as sources of pathogenic leptospires has been historically neglected (5). In particular, turtles harbor some human pathogens such as Salmonella (11) and a leptospiral pathogenic serovar (Tarassovi) has been already isolated from kidney tissue of red-eared turtles ( Pseudemys scripta-elegans) and from the surface water collected from the settling ponds of sewage disposal system where these animals lived (7). These findings are relevant in the light of the recent interest on the exposure risk to leptospires during recreational activities (3), and the risk of using these animals as pets (11).…”

“…Previous data from serologic surveys of anti-leptospiral agglutinins also reported that culture isolation is difficult in these animals (15). Indeed, the unique report of microbiologic isolation of pathogenic leptospires from turtles (kidney and cloacal) required indirect ( in vivo ) growth in hamster to recover serovar Tarassovi (7). …”

“…It is important to highlight that natural occurring humoral factors that agglutinate leptospires also occur in mammals, including humans (6,9). Moreover, among turtles whose serovar Tarassovi was isolated, high MAT titers for serovar Tarassovi exhibited considerable cross reaction with three saprophytic strains (7). Cross agglutination with saprophytic strains have also been observed in Brazilian snakes including those where leptospires could be isolated from (8,12).…”

Blanding’s turtles (Emydoidea blandingii) as a reservoir for Leptospira spp

“…To reduce or eliminate the risk of exposure to this pathogen, it is essential that relevant reservoir hosts be identified [6]. Historically, positive MAT titers have been used to determine whether wild reptiles serve as reservoirs for this important disease [14–19]; however, the serologic assay is limited in its scope, as it notes exposure but not active infection without serial samples and a rise in titer. Because of this, there is a strong argument for PCR testing of reptiles to truly characterize them as reservoirs [17].…”