names, respectively, of the North American and Russian
troglotrematoid trematodes (or flukes). These are parasitic
flatworms. Nanophyetiasis is the name of the human disease caused
by these flukes. At least one newspaper referred to the disease as
is responsible for the
, which causes an
illness in dogs that may be serious or even fatal.
Knowledge of nanophyetiasis is limited. The first reported cases
are characterized by an increase of bowel movements or diarrhea,
usually accompanied by increased numbers of circulating
eosinophils, abdominal discomfort and nausea. A few patients
reported weight loss and fatigue, and some were asymptomatic. The
rickettsia, though fatal to 80% of untreated dogs, is not known to
Detection of operculate eggs of the characteristic size and
shape in the feces is indicative of nanophyetiasis. The eggs are
difficult to distinguish from those of
There have been no reported outbreaks of nanophyetiasis in North
America; the only scientific reports are of 20 individual cases
referred to in one Oregon clinic. A report in the popular press
indicates that the frequency is significantly higher.
Nanophyetiasis is transmitted by the larval stage (metacercaria)
of a worm that encysts in the flesh of freshwater fishes. In
anadromous fish, the parasite's cysts can survive the period spent
at sea. Although the metacercaria encysts in many species of fish,
North American cases were all associated with salmonids. Raw,
underprocessed, and smoked salmon and steelhead were implicated in
the cases to date.
Consumers of raw or underprocessed freshwater or anadromous
fish, especially salmonids.
There are no tested methods for detection of
spp. in fishes. Candling with the aid of a dissecting microscope,
or pepsin HCl digestion should detect heavily infected fish.
Food and Drug
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provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a
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