schistosomiasis in ducks (LONG MSG)

Clowes sonoma at business101.com
Sun Aug 3 15:08:31 EST 1997


We are trying to gain an understanding of schistosomes which are
apparently in our man made two acre pond. Two weeks ago a brood of 3
month old domestic ducks showed symptoms of illness. One of the ducks
was euthanized and sent to UC Davis for autopsy after which we were told
it had schistosomiasis. About the same time a child who had been
swimming in the pond was diagnosed with swimmer’s itch. We also had a
similar but more severe event about 4 years ago when two people who had
been pulling pond weeds broke out in hives.. 

We have had ducks and geese for the last 5 years and are very fond of
them and as the lake is the center of activity and the reason we moved
here we are hoping that we can do something to control or eradicate the
problem. So far, we have found some related information on swimmer’s
itch but nothing on the eradication/control of schistosomes and nothing
pertaining to the effect of the parasite on the ducks. What we have read
has brought up many more questions than answers.

Is there just one type of avian schistosome? If not, do we need to find
out the exact type? I am guessing that the damage to humans is limited
to a rash but will it cause damage to other wildlife? The lake is
stocked with bass and very large catfish. There is also a large variety
of wildlife, mostly just passing through ... owls, cranes, heron, hawks,
ducks, geese, coots, moor hens, cormorants, deer, raccoons, badgers,
bobcat, cougar, etc. And will it affect livestock, cats and dogs which
sometimes drink from the pond? 

We understand snails are part of the parasite’s life cycle. Although we
have never seen any snails with shells we have seen a couple of tiny
slugs on the leg of a dead duckling found floating by the shore. We
imagine that the slugs must be living in the weed or in the mud. Is
there some way to kill them?  There are thick patches of cat tails and a
wide dense ring of parrot feather circling the lake which  needs regular
maintenance.. Since we must get in the water to pull the weed ashore, to
avoid a rash, it would be ideal if we could kill the weed and the snails
at the same time.

Our local vet doesn’t specialize in this area and so we can’t get a grip
on what to do. We have captured all the fowl and they are now caged but
we are wondering if they are all infected and if death is inevitable.
Can it be treated?  In the five years that we have kept fowl, only one
lot of 3 month old muscovy ducklings showed symptoms of illness. Of the
10 ducklings, two were healthy looking, one was found dead floating in
the water but looked fine and six had varying degrees of lameness (two
of those six had "blue" tongues and slightly mis-shaped swollen beaks
and were put to sleep.)

A week ago a pair of river otters moved in and killed 20 of the birds.
The 7 remaining muscovy ducklings were killed. We do still have the
muscovy mother (who has diarreah), the father, and as of today they have
a new brood of day old chicks. In addition to those muscovies, four
geese, a mallard and a runner survived the attack and with the exception
of the mother, appear to be healthy. The State trapper will get rid of
the otters but if we can't do something about the parasites and put the
ducks back on the lake perhaps we will just leave them.

Any information or referals on any of these topics would be greatly
appreciated.

V.Clowes



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