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Abnormal patterns of embryogenesis in Dirofilaria immitis treated with ivermectin

Published online by Cambridge University Press:  05 June 2009

J. B. Lok
Affiliation:
Departments of Pathobiology, University of Pennsylvania, 3800 Spruce Street, Philadelphia, Pennsylvania, 19104, U.S.A.
T. Harpaz
Affiliation:
Departments of Pathobiology, University of Pennsylvania, 3800 Spruce Street, Philadelphia, Pennsylvania, 19104, U.S.A.
D. H. Knight
Affiliation:
Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, Pennsylvania, 19104, U.S.A.

Abstract

The percentage composition and spatial distribution of embryogenic stages in the uteri of female Dirofilaria immitis were examined at various times after treatment with a microfilaricidal dose of ivermectin and compared to nontreated parasites. Worms sampled 42 days post-treatment (PT) exhibited an increased proportion of stretched microfilariae in the distal portion of the uterus. A decreased proportion of developed embryos was noted in the mid body region of worms sampled 42 days PT, and these forms were completely absent from the proximal area of the uterus. Relative numbers and spatial distribution of other stages remained virtually identical to controls. Radical changes in the composition and spatial distribution of embryogenic forms were noted in the uteri of a single worm sampled 80 days PT. Unlike nontreated parasites and worms sampled 42 days PT, stretched crofilariae constituted the predominant form in the distal uterus of this worm, and these stages were found in decreasing numbers throughout the proximal segments. Also, the intermediate embryogenic stages were either rare or absent.

Type
Research Papers
Copyright
Copyright © Cambridge University Press 1988

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