Although cats can become infected with Leptospira, they seldom develop signs of disease and are thus thought to be resistant. However, this study described 3 cats with confirmed naturally occurring leptospirosis. In case 1, a cat presented with a 2-week history of polyuria and polydipsia (PU/PD). The cat was dehydrated and febrile, with a urine-specific gravity of 1.007, and had small kidneys on palpation. Leptospira serology revealed a positive titer of 1:12,800 for L pomona. In case 2, a cat presented with a 10-day history of PU/PD and intermittent hematuria; a small irregular left kidney and enlarged right kidney were observed on ultrasound. Leptospira serology revealed a positive titer of 1:1,600 for L pomona. Both cats recovered after aggressive fluid therapy and long-term antimicrobial therapy. Follow-up at 1 and 3 years, respectively, revealed no evidence of residual renal insufficiency. In case 3,
a cat was examined for lethargy and anorexia; however the owner reported weight loss and PU/PD of several months’ duration. The cat re-presented severely dehydrated and in lateral recumbency and was euthanized. Necropsy showed severe, bilateral, subacute tubulointerstitial nephritis. All cats were indoor/outdoor, hunted, and lived in areas where contact with cattle and pig urine was possible. None had evidence of concurrent disease; all were FeLV/FIV negative.

Commentary
Infectious diseases are on the radar when dogs present with fevers, lameness, or renal insufficiency. In contrast, screening and treatment were instituted for common presentations of feline disease in these 3 cats but failed to produce results. It was suggested that time between exposure and clinical disease may be so far separated in cats that some of our renal insufficiency patients may actually have had leptospirosis. Before instituting regular leptospirosis screening in general practice, larger studies are needed. However, establishing lifestyle and potential exposure risk for feline patients may become more important. Further information is available for reference.1—Ewan Wolff, DVM

Source
Clinical leptospirosis in three cats (2001-2009). Arbour J, Blais MC, Carioto L, Sylvestre D. JAAHA 48:256-260, 2012.

1. 2010 ACVIM small animal consensus statement on leptospirosis: Diagnosis, epidemiology, treatment, and prevention. Sykes JE, Hartmann K, Lunn KF, et al. J VET INTERN MED
25:1-13, 2011.