The midland journal. (Rising Sun, Md.) 1885-1947, 1926-06-11
TINY GERM SPREADS
DISEASE AMONG FISH
Diminutive Parasite Attacks
the ellis.

WaSh1nAt0n.-Ihe are hSh cpl
denies as well as human epidemics.
Really serious ones due to tiny para
site rejoicing in the name ichthyoph-
thirius multifilius have occurred from
time to time in France, Germany, Hol-
land and in various parts of the United
States. This parasite attacks fresh
water fish, both in their natural en-
vironment and in aquaria with re-
sulting loss running into hundreds Of
dollars.
In recent paper H. F. Prytherch
of the United States bureau of fisher
les describes various methods of con-
trolling this disease in hatcheries, fish
farms and all places where fish are
kept in artificial confinement. To
make clear how the problem can be
attacked, he says, it is first necessary
to understand something Of the life
history Of the parasite.
"Polka Dots" Are Symptoms.
The young ichthyophthirius, accord
ing to Mr.. Prytherch, goes through
free swimming stage during which 1t
wanders around through the water in
search Of a host. On coming in con-
tact with fish it burrows into some
unscaled part, especially preferring
the gills or fins. Once embedded in
the fish's skin it grows rapidly from
the nourishment it absorbs from the
tissues and soon shows on the outside
as small white spot. Badly infected
fish are covered with these polka
dots" all over their bodies.
In few days this white body leaves
the fish and sinks to the bottom, where
it shortly undergoes a transformation
into a hard-shelled reproductive cyst.
When reproduction is complete the
cyst wall bursts and releases hundreds
of young parasites of the free-swim-
ming stage.
Mr.. Prytherch states: "There are
two general methods for treating the
disease-first, by killing the parasites
while they are attached to the fish,
and second, by destroying them after
they leave the fish and are free-swim-
ming in the water. The first general
method can be used to hold the disease
in check, but will not completely wipe
it out"
Alum Sulphate Helps.
The logical time to begin treatment,
he continues, is when the first symp-
towns nf tho dicaoSa oppoor ond tho
whole fight in controlling the disease
should be directed against reinfection.
Direct application of alum sulphate
has been found most efficacious in rid
ding the fish of the parasites. The
healing action of the alum leaves the
patient" in less weakened condi-
ton than any of the various other
chemicals tried so far for this pur-
pose.
The second method which attacks
the adult parasite after it has left
the fish is more successful and should
be utilized, says Mr.. Prytherch, wher-
ever possible. It consists simply in
placing the fish in swiftly running
WAFER WHcIc TIE PAL dSltcS WILL NC
carried away before reproduction can
take place. The overflow should be
carried off both at the top and the
bottom to take care of any that do
not fall directly to the bottom. In
fected fish, in warm weather, 1t is
stated, may be cured in this way in
a week or ten days and further cpl
denies prevented by quarantining
new stock in running water. In some
instances swiftly flowing streams may
be fenced off and used for this pur
pose by leaving the fish in the inclos-
ure until cured.
Tadpoles and goldfish kept in tanks
with fishes subject to this disease
have been found extremely helpful in
keeping it down, since they prey on
the parasites for food.