Evening star., 1933-05-28

~ to entomOlogtStS as Dermacen-
n tor variabiliS and to laymen as
1 \ the dog tick"-the carrier Of
the virus of the Eastern type
Of the deadly Rocky Mountain spotted
tever-is presenting one of the most
difficult problems they have ever faced
to scientists of the Public Health
culture.
In the normal course of events the
virus Is expected to be more and more
widely distributed through the District
of Columbia- Maryland Virginia area
every year. But, according to DR..
Maurice Hill, chief of the division of
zoology of the Bureau of Animal In
dustry, study of the habits and life
history of the bug shows no point of
attack which promises to do much good
in reducing its numbers. Such insects
as the mosquito, carrier of yellow fever
and malaria, have weak spots in their
life cycles, by striking ct which it is
possible to reduce their numbers to the
point where they DO little harm.
DR.. Hall is largely responsible for
the campaign which has practically
cleaned the country OF the other great
tick-carried disease-the tick fever of
cattle which few years ago caused
tremendous losses to the live stock in
dustry. But that was comparatively
child's play compared to this new
menace. he says, since the cattle tick
fed only on cattle and occasionally
deer. 1t could be starved out of any
infected area merely by removing the
cattle temporarily.
Feeds on Human Blood.
The difficulty with the dog tick, DR..
Hall points out, is that it apparently
feeds on the blood of a large number
of warm-blooded animals, including
man. Only a general cleanup OF ami
mails, underbrush and weeds through
the tick infested area would do much
good, and such task is SO huge that
it would be impractical.
A considerable reduction of the risk
could be brought about, it was pointed
out at DR.. Halls Office, If all the va
cant lots and back yards throughout
Washington could be cleared, either by
the owners or by the city, of tall weeds
and underbruSh. A child is most likely
to obtain the tick from Waist-high
growths But there would still be left,
said DR.. Hall, all the flowers, rose
bushes and other shrubbery. These
harbor the tick as well as anything
else They are less likely to be picked
up on well-mowed, cleanly kept lawns,
although they may be found even there.
1T looks to me-" sadly remarked the
veteran zoologist who has been in the
forefront of the fight against many
human and animal diseases, "as if we
must wait until we have civilized
society before We can hope to get rid
of the dog tick. And 4 hardly expect
that for a few generations yet. Such
society, confronted with such a seri-
GUS enemy, would go ahead by the most
direct method and eliminate it."
Only Hope in Research.
At present, it was emphasized, the
only hope lies in intensive and continu-
Gus scientific research which may re-
veal Unexpectedly and economically
practicable point of attack. There is
every likelihood, DR.. Hall said, that
virus carrying ticks, apparently abun-
dant in nearby Maryland, have pene-
and may be picked up in any vacant
lot.
The following description Of the
symptoms and progress of Rocky Noun
tain spotted fever was given out by the
Public Health Service, whose officers
are practically the only physicians in
this part of the country who have had
any experience in dealing with the
disease:
THE period between the tick bits
and the first symptoms varies from 2
to 10 or IL days. Onset may be gradual
over period of l or more days, or it
may be sudden. If it is gradual, as is
usually the case, the appearance of the
fever is commonly preceded by period
that is mainly characterized by weak
ness, but there may also be chilly SEN
sations. A definite chill frequently fol-
lows. With the appearance of the
fever the following symptoms are pres
ent, in whole or in part:
"Heachache in front or back of head