Establishment of a leptospirosis model in guinea pigs using an epicutaneous inoculations route

Abstract

BackgroundLeptospires are presumed to enter their host via small abrasions or breaches of the skin. The intraperitoneal route, although commonly used in guinea pig and hamster models of leptospirosis, does not reflect conditions encountered during natural infection. The aim of this study is to develop a novel leptospirosis guinea pig model through epicutaneous route and to elucidate the pathogenesis of leptospirosis in experimental guinea pigs by comparing the data from other studies using different infection routes.MethodsThe guinea pigs were inoculated with 5 × 108 Leptospira interrogans strain Lai onto either shaved-only or abraded skin. The guinea pigs were sacrificed at 2, 8, 24, 48, 72, 96 and 144 h post-infection (p.i.) followed by harvest of the lungs, liver, kidneys, spleen, and the skin around the inoculated sites for further examinations. Hematoxylin and eosin (HE) staining and electron microscopy were used to detect the pathologic changes. Real time PCR and immunohistochemistry staining were performed to detect dynamic distribution of leptospires in blood and tissues, respectively.ResultsIn the guinea pigs with abraded skin inoculations, leptospires were detected in blood as early as 2 h post infection (p.i.) and then disseminated to the liver, lungs and kidneys of almost all animals within 96 h p.i.. Leptospires were also detected engulfed in the swelling vascular endothelial cells and were frequently aggregated around the capillaries in the dermis and subcutaneous tissue under the inoculated site. For the guinea pigs with abraded skin inoculations, hemorrhage at the dermis around the inoculated site was found before the appearance of internal organs hemorrhage, severe lesions such as hemorrhages in the lungs, nephritis, jaundice, haematuria were also observed, and two of seven guinea pigs died at 144 h p.i. while no lesions and leptospires were detected in the shaved-only guinea pigs using the same dose of strain Lai.ConclusionIntact keratinocyte layer is a very efficient barrier against leptospires, and intact skin can prevent the infiltration of leptosipres to the host. Leptospires can penetrate abraded skin and quickly establish a systemic infection by crossing tissue barriers. We have successfully established a novel leptospirosis guinea pig model through epicutaneous inoculations route, which replicates a natural course of infection and appears to be an alternative way to investigate the pathogenesis of leptospirosis, especially in terms of early stage of host-pathogen interactions. This novel model may also be advantageous for studies of the mechanisms involved in cutaneous barriers and epidermal interactions with this organism.

A new model of self-resolving leptospirosis in mice infected with a strain of Leptospira interrogans serovar Autumnalis harboring LPS signaling only through TLR4

“…8 L. interrogans strain Lai did not cause any obvious lesions in C57BL/6 WT mice up to 7 dpi, and this indicated that L. interrogans strain 56606v induced typical acute leptospirosis symptoms in mice in a strain-specific manner.…”

Development of the central nervous system in guinea pig (Cavia porcellus, Rodentia, Caviidae)

“…This popularity has increased the interest in its behavior, physiology and management, leading it to be used as an experimental animal (Taylor & Lee 2012, Dumitrascu et al 2013). Due to anatomical and physiological similarities, related to pregnancy and placentation (Miglino et al 2004, Mess 2007, Vasconcelos et al 2013, this species became extremely important as an experimental model for human placentation, as well as for respiratory diseases (Canning & Chou 2008, Skerry et al 2013), cardiovascular problems (Zaragoza et al 2011), and bacterial, viral and fungal infections (Pica et al 2012, Zhang et al 2012.…”

Hemorrhagic, Hemostatic, and Thromboelastometric Disorders in 35 Dogs with a Clinical Diagnosis of Leptospirosis: A Prospective Study

“…First, leptospirosis is assumed to cause systemic vasculitis, which could be an important mechanism of tissue damage and hemorrhagic tendencies . Inflammation of the vascular endothelium may be a consequence of direct invasion by infectious agents or of immune mechanisms . Second, thrombocytopenia is a well‐documented feature of leptospirosis (14–58% in naturally occurring leptospirosis in dogs) .…”