Treatment and prevention of leptospirosis

INTRODUCTION

Leptospirosis is a zoonosis with protean manifestations caused by the spirochete Leptospira interrogans. Synonyms for the disease include Weil's disease, Swineherd's disease, rice-field fever, cane-cutter fever, swamp fever, mud fever, hemorrhagic jaundice, Stuttgart disease, and Canicola fever.

The treatment and prevention of leptospirosis will be presented here. The epidemiology, microbiology, clinical manifestations, and diagnosis of this disease are discussed separately. (See "Microbiology, epidemiology, clinical manifestations, and diagnosis of leptospirosis".)

TREATMENT

The vast majority of infections with Leptospira are self-limiting. Although penicillins, tetracyclines, chloramphenicol, and erythromycin have antileptospiral activity in vitro and in animal models, it remains controversial whether antimicrobials produce a beneficial effect in mild human leptospirosis since the illness has a variable natural history. Nevertheless, if the illness is severe enough to result in a physician visit and the diagnosis is recognized, antibiotic therapy should be given.

Efficacy — Two small randomized trials have demonstrated benefit from antimicrobial therapy. In a study of 29 patients who received doxycycline (100 mg PO twice daily) or placebo, doxycycline shortened the illness by an average of two days and prevented shedding of the organism in the urine [1]. In a study of 42 patients with severe leptospirosis treated with penicillin (6 million units daily) or placebo, those who received penicillin had fewer days of fever, more rapid resolution of renal function, and a shorter hospital stay; penicillin therapy also prevented urinary shedding [2].

Two randomized trials have compared penicillin (6 million units daily) with ceftriaxone (1 g every 24 hours), cefotaxime (1 g every six hours), and doxycycline (100 mg IV every 12 hours); all regimens were observed to be therapeutically equivalent [3,4]. In one randomized trial of 264 patients with severe leptospirosis in northeastern Thailand comparing cefotaxime, penicillin G and doxycycline, all the regimens had similar efficacy for leptospirosis [4]. Among these patients 132 patients were diagnosed with rickettsial infection; for these patients, treatment with doxycycline was superior to treatment with penicillin G. Therefore, doxycycline or cefotaxime (or ceftriaxone) are appropriate therapies for the treatment of severely ill patients in areas endemic for leptospirosis and rickettsial infection.