Comparative Histopathology of Acanthocephalan Infections in Some Freshwater Fishes
1980
Schelhaas, Douglas P.
The objective of this study was to compare the intestinal histopathology of common suckers (Catostomus commersoni), creek chubs (Semotilus atromaculatus) and walleyes (Stizostedion vitreum) infected with acanthocephalans. Special emphasis was placed on the extent and type of host tissue response to these infections. Intestinal tissues of suckers infected with Octospinifer macilentis and Pomphorhynchus bulbocolli, creek chubs possessing Neoechinorhynchus saginatus and walleyes parasitized by N. cylindratus were excised and fixed in 5% formalin or Bouin's solution. Comparative tissue samples were also taken from uninfected fishes. All tissues were embedded in paraplast and sectioned with a rotary microtome. Sections fixed with Bouin's solution were stained with Malloy's triple connective tissue stain, while those preserved in formalin were stained with Delafield's hematoxylin and eosin Y. The acanthocephalan infections produced no apparent detriment to the general health of these fishes. However, tissue sections revealed varying amounts of damage and tissue reaction to the parasites. These differences are attributable to the following reasons: deapth of attachment of the worm is the primary cause for variations in host tissue reactions; the morphology and depth of mucosal folding determines where and how deeply the worm must attach in order to become firmly anchored; and the relative thickness of the lamina propria and tunica muscularis influences the amount of damage resulting from worm attachment. A comparison of O. macilentis and P. bulbocolli infections in suckers showed that the difference in damage and host response is primarily due to the vast differences between the lengths of their presomas.
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