The use of imaging to detect schistosomes and diagnose schistosomiasis

Abstract

Summary Several imaging modalities have been employed to examine schistosomes and monitor schistosome-induced pathology. Ultrasound is a non-invasive imaging method that has long been used in the laboratory and in the field to evaluate pathological changes, notably fibrosis, that arise as a consequence of the host response to schistosome eggs lodging in a variety of tissues. Ultrasonography has been widely used to monitor changes in the extent of fibrosis and in spleen/liver enlargement following chemotherapeutic treatment for schistosomiasis. Imaging methods to monitor schistosomes themselves in vivo (as opposed to detecting schistosome-induced pathology) include positron emission tomography (PET) and fluorescence molecular tomography (FMT). Both approaches rely on schistosome uptake of tracers that are introduced into infected animals and that can be detected externally. These methods have been used to successfully detect schistosomes in vivo and to monitor their elimination following chemotherapeutic treatment. Direct monitoring of live schistosomes in vivo has been achieved using intravital microscopy (IVM), when the infected tissues of anaesthetized animals are exposed. Finally, schistosome eggs have been visualized by confocal laser scanning microscopy in infected mice as well as in a human patient with schistosomiasis hematobium. Further advances in imaging technologies seem likely to provide greater insight into disease progression and into the biology of schistosomes in the most relevant setting – within a live animal.

Histological study on the possible therapeutic role of bone marrow derived mesenchymal stem cells in a model of Schistosoma mansoni infestation of spleen of mice

“…Furthermore, (SEA) might cause shift of immune response to Th2. Also, this antigen had promoted leucocyte chemotactic activity especially eosinophils [23] and this was in accordance with our results. However, eosinophils were responsible for the cytokine profiles which had been attributed to a Th1 to Th2 shift.…”

“…These results were in accordance with [21,22] who explained that eggs deposition constitutes the major pathogenesis of schistosomiasis, with egg-laying beginning four weeks after infestation and reaching a peak at eight weeks post-infestation. Furthermore, Skelly [23] postulated that in contrast to the adult worms, parasite eggs via soluble egg antigen (SEA) provoked a potent chemotactic activity and strong inflammatory reaction resulting in stimulation of inflammatory cells and cytokines (including interferon-γ, TNF-α and ILs). Consequently, the egg was surrounded by a variety of immune cells to form a unit called a granuloma.…”

Live imaging of collagen deposition during experimental hepatic schistosomiasis and recovery: a view on a dynamic process

“…Traditionally, histology or quantitative PCR have been used to measure the degree of fibrosis in schistosomiasis and other liver diseases [14,15], although these methods have limitations as will be discussed further below. The value of in vivo approaches to understand the biology and lifecycle of schistosome parasites has been recently reviewed [16]. We sought to demonstrate the capacity of whole animal imaging in charactering the chronic pathology caused by the eggs of schistosome blood flukes.…”

Intravital imaging of host‐parasite interactions in organs of the thoracic and abdominopelvic cavities

“…Two studies have used IVM to investigate parasite dynamics and immunopathological processes in the liver. One of the first Schistosoma studies using IVM was published in 1980 (Bloch, ; Skelly, ). Although fluorescent reporters and transgenic animals were not as widely available as they are now, this study was a major breakthrough as it described for the first time Schistosoma dynamics in vivo .…”