Diagnosis of leptospirosis by dark-field microscopy of blood samples and culture

Abstract

Leptospirosis, one of the most extended zoonosis in the world is considered a reemergent disease. It is produced by the pathogenic species of the genus Leptospira. There are approximately 13 of 17 species described up to date. These species are indistinguishable morphologically and their taxonomic classification is done by molecular methods.
Leptospirosis presents with multiple unspecific clinical symptoms that make it difficult to confirm the case. To verify the diagnoses, the medical personnel need to know how to recognize the clinical manifestations for leptospirosis and to corroborate a good diagnostic suspicion, in addition to ordering the appropriate tests to the laboratory for: 1) dark field microscopy visualization of the bacteria in blood samples, urine or postmortem tissues which need to use special stains like silver stain or immunofluorescence; 2) having positive culture for leptospirosis from blood, urine, CSF or of tissues postmortem; 3) having an increase (fourfold rise) of the tires in microagglutination test from two serum samples taken with an interval of 15 days apart, 4) an elevated unique title (>1:400) using microagglutination for serological diagnosis or IgM detection test, and 5) positive PCR assay in blood, urine, CSF or tissues postmortem.
Due to the fact that the first two tests for diagnosis needs a trained personnel for Leptospiras visualization, we would like to present to the medical community reference images of Leptospira species that can be observed by dark field microscopy from as blood as cultures. It is necessary to have methods for leptospirosis in the public health laboratories; additionally, to have qualified personnel to realize them. This will allow confirming a clinical diagnosis with symptoms that resemble other endemic diseases in Colombia, like dengue and malaria.