Identificação de novos antígenos para diagnóstico sorológico de leptospirose canina

Abstract

Leptospirosis is a neglected zoonosis with a worldwide distribution. It is caused by pathogenic bacteria belonging to the genus Leptospira. This pathogen enters the host through the mucous membranes or skin abrasions and can be transmitted by direct contact with infected animals or indirect contact with contaminated water and soil. The only commercially available vaccines are based on inactivated bacteria, they have several limitations and are mainly for veterinary use. Dogs are potential disseminators of the pathogen in urban environments, representing a risk to human beings. Canine leptospirosis can manifest as fever, chills, uveitis, kidney and liver damage, among other signs. Laboratory diagnosis is limited; the available methods take time and are not easily applied in an endemic setting. In addition, diagnosis tends to be laborious, expensive and often has poor sensitivity. Thus, the true global burden of leptospirosis is worryingly underestimated. Therefore, it is extremely important to develop a diagnostic assay that is sensitive, specific, easy and quick to perform and that is able to detect the disease in its early phase. Outer membrane proteins are widely studied in the fields of vaccinology and diagnosis. In this work, eight novel recombinant proteins identified by bioinformatics were produced and evaluated as potential targets for the development of an indirect ELISA using canine sera. Amongst them, OmpL125 protein, in an ELISA-IgM, presented 90,9% sensitivity and 78,2% specificity; and in an ELISA-IgG presented 81,8% sensitivity and 73,9% specificity, with these being the best results among the analyzed proteins. These results are not suitable for a new commercial diagnostic method. These serological tests are neither satisfactory nor reproducible for the diagnosis of canine leptospirosis.