Immunohistochemistry, histopathology and ultrastructure of Gasterosteus aculeatus tissues infected with Glugea anomala

Abstract

Immunohistochemical and histopathological studies were conducted on a population of 3-spined sticklebacks Gasterosteus aculeatus (L.) from Loch Airthrey (Stirling, Scotland) naturally infected with the microsporean Glugea anomala (Moniez 1887). Of the 55 host specimens that were examined, 16 (29.09%) were infected, the intensity of infection ranging from 1 to 4 xenomas per fish, which were principally located within the central portion of the body lateral flank musculature. All 32 G. anomala xenomas examined were mature, their diameter ranging from 936 to 2232 µm, and their walls of presented a laminar structure. Subcutaneously situated xenomas protruded from the fish body surface, whilst xenomas encountered within the intestine were seen to cause distortion. Light and electron microscopical observations confirmed a host cellular reaction around the xenoma, seen by the presence of eosinophile granule cells (EGCs), and some neutrophils. The occurrences of rodlet cells among the intestinal epithelial cells, and in close proximity to the xenoma wall, were observed in certain specimens. Outside the xenoma wall, macrophage aggregates (MAs) were commonly encountered. Within the xenoma wall, the presence of eosinophile granular cells immunoreactive to the anti-serotonin serum was also recorded. Further immunohistochemical tests revealed that a high number of nerve fibres running along the white lateral muscle fibres were immunoreactive to bombesin-, galanin-, and leu-enkephalin-antisera. Nerve fibres containing bombesin-and leu-enkephalin-like substances were also observed in the connective inflammatory tissue around the protozoan cyst, while neurons in the spinal ganglia were immunoreactive to met-enkephalin, and serotonin antisera. The control for the specificity of immunohistochemical reactions was performed using preabsorption tests of each antiserum with the corresponding antigen, and no immunoreactivity was noticed. The data presented are discussed in relation to the occurrence of G. anomala, which alters the pattern of nerve fibres present in the host. Specifically, the protozoan induces a response in the stickleback nervous system, the reaction of which is revealed through the application of immunohistochemical techniques.

Histopathology, ultrastructure and immunohistochemistry of Coregonus lavaretus hearts naturally infected with Ichthyocotylurus erraticus (Trematoda)

“…In the study of Vogelbein et al (1987), who found MAs in association with parasite infections, it was suggested that their presence represents an inflammatory rather than a granulomatous reaction. The findings of the current study and those of Dezfuli et al (2004) lend support to Vogelbein et al's (1987) hypothesis.…”

“…A bombesin-like substance was also encountered within the thin nerve fibres in the inflammatory connective tissue of Gasterosteus aculeatus infected with the protozoan Glugea anomala (Dezfuli et al 2004). The findings from these and those of the current study support the hypothesis of Dezfuli et al (2004), who suggested that the presence of bombesin at the site of tissue inflammation in fishes acts as a putative neurotransmitter in the neo-formed network of nervous fibres.…”

“…The MAs were observed in histological sections of 14 powan hearts, and their proliferation has been frequently associated with both physiological and pathological factors including starvation, aging, intoxication and the presence of infectious disease (Vogelbein et al 1987, Couillard & Hodson 1996, Couillard et al 1999. The presence of MAs have been reported for Rivulus marmoratus (Poey) experimentally infected with the protozoan Calyptospora funduli Overstreet, Hawkins & Fournie, 1984(Vogelbein et al 1987) and also for Gasterosteus aculeatus infected with the microsporean Glugea anomala (Dezfuli et al 2004). In the study of Vogelbein et al (1987), who found MAs in association with parasite infections, it was suggested that their presence represents an inflammatory rather than a granulomatous reaction.…”

“…It is well known that the diffuse endocrine, nervous and immune systems cooperate to elicit host responses to these helminths (Fairweather 1997) and to achieve this signal molecules (herein neuromodulators) are involved in communicating between the cells of the 3 systems (O'Dorisio & Panerai 1990). The presence of neuromodulators in other host -parasite systems have been studied, including the effect of Pomphorhynchus laevis (Müller, 1776) and Cyathocephalus truncatus (Pallas, 1781) on the gut neuroendocrine system of Salmo trutta L. (see Dezfuli et al 2000Dezfuli et al , 2002bDezfuli et al , 2003a and that of the protozoan Glugea anomala (Moniez, 1887) on the peripheral nervous system of Gasterosteus aculeatus L. (Dezfuli et al 2004). These studies suggested that the presence of a parasite within a host induces the formation of a new network of nervous fibres at the inflammatory site, as demonstrated by the presence of a number of neurotransmitters (e.g.…”

“…These studies suggested that the presence of a parasite within a host induces the formation of a new network of nervous fibres at the inflammatory site, as demonstrated by the presence of a number of neurotransmitters (e.g. bombesin, galanin and substance P) at the site of infection (Dezfuli et al 2002b(Dezfuli et al , 2004. While a similar response may be expected by the powan-digenean system, given the lack of information on the nervous system of parasitised and uninfected heart tissue, our study assesses the occurrence of a range of neuropeptides in the hearts of Coregonus lavaretus parasitised with the metacercariae of Ichthyocotylurus erraticus.…”