Evening star., 1932-08-19
DOG TICK DEMON
TOU. S. SCIENTISTS.
Carrier of Spotted Fever Now
Gets Blame for AnapIas-
mosis, Cow Disease.
BY THOMAS r.. HENRY.


Department of Agriculture specialists
are banned, temporarily at least, by the
challenge Of the dog tick.
This tough little bug. hitherto con-
sidered only as a nuisance, but wh1cn
suddenly has become one OF the most
n1enacing enemies of man and the DO
rriestic animals, seems equipped TO beat
science at every turn. 1t Is the carrier,
throughout the Eastern states, OF tne
deadly Rocky Mountain spotted fever,
which at present is sinister threat for
the entire country. 1t has also been
found to be the carrier, 1t was an
nounced at the geological division OF the
Bureau OF Animal Industry today. OF
newly discovered and fatal disease OF
cattle, anaplasmosis, which has prcken
ont in the South and West.
1t is because of the menace to cattlc
that the little bug is engaging the at
tention of the Agriculture Department
veterinarians, while the Public Health
Service is attending to the human slde
of the problem. The special dinculty OF
any campaign for eliminating the pest
according to DR.. Maurice Hall, veteran
fighter of similar menaces. hes IN tne
fact that it is a "three-hcst insect; II
goes through three life stages, each on
a QlueT6Ib NAoPp'o
ground between each one.
Change to "Nymphs."
The larvae which hatch from the
eggs Immediately attach themselves 70
some small mammal, preferably rat
or mouse. After filling themselves WIN
the blood CT this animal they drop To
the ground and shed their skins, emerg-
inc in the state known as the "nympn
stage" Again these attach themselves
to any warm -blooded animal wnlcn
comes along, preferably dog. AGAIN
they drink their fill of blood and drop
off to undergo the second metamorpnosis
into the adult tick. Again tney attacIi
themselves to the first warm -pioooeo
animal that comes along, preferably
dog. But If they cannot find a cog
man or a COW will serve the purpose.
The insect is abundant over the entire
country, except for limited regions IN
the Rocky n ountain area. 1t
native American animal, adapteo
through countless generations to survive
In yery diverse environments. Ns
almost universal distribution, combined
with its three host" life cycle, DR.. Hail
saws makes it impossible to locate any
,,nint upon which to concentrate an
attack. The only plan for eliminating
the insect which holds forth any prom
Use of success, he explains, would pe SO
radical. expensive and dangerous tnat
Il would bes justified only by the orest
emergency, and nobody knows whas
would be the accompanying effects OF
s,,rh a far-reaching disturbance OF the
balance of nature This plan would call
for the practically complete burning
every spring of all the underbrusn
throughout the dog tick area. II woulo
destroy the eggs before they hao
chance to hatch.
Fire Used I'm South.
This is done successfully, he points
out through the pine-barren regions OF
the South. where the growth OF under.
brush is very slight. Fires are lit ana
kept under rigid control. which burn
through the woods without injurmg tne
trees. But in the Virginia Maryland
cegion, where the underbrush Is mucn
heavier, such fires probably woulo
destroy the trees, DR.. Hall fears. Iney
certainly would destroy much OF the
beauty Of the woods, particularly the
fiowering bushes, and reduce nature TO
a dreary monotony. Yet the under
brush seems to be the only feasible
point at which the tick can be attacked,
and even such radical procedure
might prove justified If it should turn
ont that men and cattle cannot persist
successfully in the same area as the
insect.
what direful potentialities the TICK may
have acquired. apparently quite SUD
denly. It's capacity for transmitting
the deadly cattle disease was hitherto
unsuspected Nobody knows how widely
"a .sE nj a
spotted fever has spread among the
Eastern ticks. 1t should be empha-
sized, DR.. Hall points out, that the dog
tick and the wood tick are the same
insect. Picnic groves have been trans
formed into potential death traps.
The cattle disease, which Is being
studied by DR.. Charles w. Rees OF the
Bureau of Animal Husbandry, Is char
acterized at the start by sudoen loss
of flesh and suppression OF the now
of milk. Weakness and stiffness OF
gait develops and the cows are in
clined to lie down frequently. Com
plete suppression OF milk usually fol-
lows, and respiration and pulse De-
come rapid. Death may come IN from
two days to week after the nrst
symptoms are noticed. The disease mas
been recognized before in the tropics
and in Southern Europe. where 1t prob
ably is spread by some other means.
Tick Fever Spread.
The new challenge to the veterina-
rians comes when, after long hght,
they have practically eliminated from
the United States one tick which was
proving a dangerous cattle pest. II
was the cow tick, responsible for the
spread Of the dreaded tick fever through
herds over a large part OF the country.
But this was simple, DR.. Hall says. The
COW tick was a one-host insect. 1t laid
its eggs on the COW and went through
all three stages Of its development on
the same animal. All that was re-
3uired was to dip" the cattle.
But even this DR.. Hall points out, was
an expensive procedure in some parts OF
the country and the complete ellmina-
ton still is held up because OF the cost.
It still persists in Arkansas, louisiana
and Eastern Texas, where the herds
scatter in deep swamps. In virginia
the problem finally was solved by using
dogs for great cattle round-ups through
the swamp areas.
Public Health Service officials are
confident that the spotted fever menace
through the dog tick area can be Kept
under control, If worse comes to worse,
bv wholesale vaccinations OF persons
living in rural areas. There is no vac
cine. however, for anaplasmosis.
Thus far, at least the dog tick has
shown no signs of carrying the virus OF
a second strange human disease which