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The life history of Neoechinorhynchus rutili (Mueller, 1780) and its development in the intermediate host (Acanthocephala ; Neoechinorhychidae)

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Title The life history of Neoechinorhynchus rutili (Mueller, 1780) and its development in the intermediate host (Acanthocephala ; Neoechinorhychidae)
Names Merritt, Sheridan Vernon (creator)
Pratt, Ivan (advisor)
Date Issued 1963-08-01 (iso8601)
Note Graduation date: 1964
Abstract The fish of Suttle Lake, Oregon, have been found to harbor
an acanthocephalan parasite, which lives attached to the mucosa of
the intestine. Between July 1961 and January 1963, several hundred of
these fish were exarnined and nearly every one was infected
with this parasite, which was identified as Neochinorhynchus rutili
(Mueller, 1780).
Since relatively little is known about the life cycle and post-embryonic
development of N. rutili, it was decided to study these
problems in the laboratory.
Of 267 ostracods (Cypria turneri) examined, 64 or 24 percent
were found to harbor the cystacanth or juvenile stage. Some of
these ostracods were fed to two small infection-free cutthroat trout.
The first fish was fed five and the second was fed nine. Two weeks
later one male acanthocephalan was found established in the intestine of the first fish and four, including three females in the
second.
It was possible to follow the development of the parasite
from the emergent embryo to the infective cystacanth. Several
infection-free ostracods from a local pond were infected by allowing
them to feed on shelled embryos from the body cavity of an adult
worm. The ostracods were then dissected periodically and the
stages of development were studied and drawn.
The life cycle can be summarized in the following way. The
shelled embryos are released by the adult worm into the intestinal
lumen of the fish and they pass out with the feces. These "eggs"
are ingested by ostracods (Cypria turneri). The embryo emerges
as an acanthor and penetrates the wall of the gut into the hemocoel
where it metamorphoses through acanthella to the cystacanth or
juvenile stage in 48 to 57 days. This final stage is infective when
eaten with the ostracod by the fish.
Genre Thesis/Dissertation
Topic Neoechinorhynchus rutili
Identifier http://hdl.handle.net/1957/48718

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