ABSTRACT
Depending on its time of evolution, leptospirosis
presents two phases: acute and chronic. The chronic leptospirosis is widely accepted in animals and, until
recently, this was denied in humans. Since the 1990s, we have studied dozens of
cases demonstrating the chronicity of leptospirosis, including an asymptomatic
or undetermined form that may remain so
throughout life time or may evolve into a definitive chronic disease and/or worsen, becoming severe cases. A fundamental part
for its demonstration is the isolation and characterization of the etiologic
agent. In this work, the first 14 isolations of Leptospira sp. are
reported from human chronic leptospirosis and an African lion diagnosed with
chronic leptospirosis, obtained between 2002 and 2006, in urine, blood, and
skin microbiopsies. From the 14 isolations from patients with chronic
leptospirosis, one of the cases is apparently congenital and two are from
patients with chronic asymptomatic leptospirosis. The diagnosis was performed
by means of videorecording in darkfield microscopy in blood and urine, specific
culture media, and MAT serology. Argentic impregnation and detection of
specific antigen by immunostaining in blood were performed in seven patients;
in two patients, skin microbiopsies and biopsies were performed. All cases were
positive by video-recording
in darkfield, one of them MAT was 1:160, and the rest were positive at low
titers (≤1:80). The two skin biopsies were positive by argentic impregnation
and immunostaining. Eleven isolates were obtained from blood, two from skin,
and one from urine. The isolates were characterized by monoclonal antibodies as Leptospira serovar Pomona. L. Pomona is considered of low virulence
and high adaptability to the host, and is frequently associated to chronic
leptospirosis in animals. In our study, it was the only isolated serovar, including
the one isolated from the lion, which would seem the most common one in our
country and responsible for a large portion of cases of chronic human
leptospirosis.