Serovar distribution of a DNA sequence involved in the antigenic relationship between Leptospira and equine cornea

Paula Ma Lucchesi,Guillermo H Arroyo,Alberto E Parma

doi:10.1186/1471-2180-2-3

Paula Ma Lucchesi, Guillermo H Arroyo + Show 1 more

Open Access

https://doi.org/10.1186/1471-2180-2-3

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Abstract

BackgroundHorses infected with Leptospira present several clinical disorders, one of them being recurrent uveitis. A common endpoint of equine recurrent uveitis is blindness. Serovar pomona has often been incriminated, although others have also been reported. An antigenic relationship between this bacterium and equine cornea has been described in previous studies. A leptospiral DNA fragment that encodes cross-reacting epitopes was previously cloned and expressed in Escherichia coli.ResultsA region of that DNA fragment was subcloned and sequenced. Samples of leptospiral DNA from several sources were analysed by PCR with two primer pairs designed to amplify that region. Reference strains from serovars canicola, icterohaemorrhagiae, pomona, pyrogenes, wolffi, bataviae, sentot, hebdomadis and hardjo rendered products of the expected sizes with both pairs of primers. The specific DNA region was also amplified from isolates from Argentina belonging to serogroups Canicola and Pomona. Both L. biflexa serovar patoc and L. borgpetersenii serovar tarassovi rendered a negative result.ConclusionsThe DNA sequence related to the antigen mimicry with equine cornea was not exclusively found in serovar pomona as it was also detected in several strains of Leptospira belonging to different serovars. The results obtained with L. biflexa serovar patoc strain Patoc I and L. borgpetersenii serovar tarassovi strain Perepelicin suggest that this sequence is not present in these strains, which belong to different genomospecies than those which gave positive results. This is an interesting finding since L. biflexa comprises nonpathogenic strains and serovar tarassovi has not been associated clinically with equine uveitis.

Highlights

Horses infected with Leptospira present several clinical disorders, one of them being recurrent uveitis
A region of the leptospiral DNA fragment that encodes epitopes involved in the antigenic cross-reactivity between this bacterium and equine cornea was subcloned and sequenced
As primers G1/G2 and B64-I/ B64-II are specific for pathogenic leptospires, the presence of leptospires in the aliquot taken from the culture of L. biflexa serovar patoc was determined by microscopic observation. These results suggest that in the nonpathogenic strain analysed, the sequence related to the antigen mimicry with equine cornea is not present

Summary

Introduction

Horses infected with Leptospira present several clinical disorders, one of them being recurrent uveitis. A common endpoint of equine recurrent uveitis is blindness. Leptospirosis is a widespread disease that affects wild and domestic animals as well as humans [1]. Animals which have recovered from acute leptospirosis may develop a carrier condition, shedding leptospires in their urine [2]. Horses infected with Leptospira present several clinical disorders, one of them being recurrent uveitis or iridocyclitis [3,4]. In equine recurrent uveitis (ERU), episodes of acute anterior uveitis are separated by quiescent periods of variable duration [5]. Lacrimation, photophobia, myosis, corneal edema and (page number not for citation purposes). The inflammatory process may lead to anterior or posterior synechiae, cataract, iris atrophy, retinal detachment, lens luxation and corneal opacity [3,5]

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