Immunomodulatory treatment with thalidomide in experimental leptospirosis in Golden Syrian hamsters (Mesocricetus auratus).

BACKGROUND

The benefit of antibiotics in leptospirosis is limited when treatment is started four days after symptoms appear, and new adjuvant therapeutic options are urgently needed.

METHODS

Hamsters (Mesocricetus auratus) were infected by Leptospira interrogans strain L1-130, and groups were assigned based on no treatment (NONE), thalidomide only (TAL), ampicillin only (AMP) or both (AMP-TAL). Treatment was started two days after the onset of symptoms (experiment 1) and immediately after detection of the first death (experiment 2).

RESULTS

Experiment 1: all hamsters from the groups AMP and AMP-TAL survived (n=8), while all hamsters from groups NONE (n=6) and TAL (n=8) died. The AMP and the AMP-TAL groups showed no renal or liver pathology and absent or very low leptospiral burden in target organs. Experiment 2: lethal outcome was observed in 6/6 hamsters in the NONE group, 8/8 in the TAL group, and 6/8 in both the AMP and AMP-TAL groups. Thalidomide showed no survival benefit when compared to hamsters treated with ampicillin alone. The TAL, AMP and AMP-TAL groups had very low tissue leptospiral counts.

CONCLUSION

Thalidomide had minimal impact on survival in the late treatment of leptospirosis hamster model.