Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-02-28
MOUNTAIN DISEASE
NOW |NVADES EAST
Spotted Fever From Rockies
Is Diagnosis of Fatal
MaIady Found Here.
Continued From First Page.)

greatly ameliorates its course when II
Is contracted. The manufacture of this
vaccine from the bodies of the animal
ticks is an extremely costly, laborious
and time-consuming process and never
has been taken over by commercial
drug manufacturers.
Determination of the spotted fever in
vasion went hand in hand with the in
Vestigation of q typhus outbreak last
year, which led to the discovery that
the virus of this disease is carried by
rat flea. Early in the study 1t was
found that cases reported from the
States did not exactly correspond to
the clinical picture of typhus and were
closer to spotted fever. Many of these
cases gave a history Of tick bite short
time preceding the onset and there was
seldom evidence of rat infestation.
In the endemic typhus cases, confined
mostly to the cities, there were nc
complications and convalescence as a
rule was speedy. There were no deaths
Occasionally slight torpor or disorien-
tation persisted for several days. In
the spotted fever cases convalescence
was more protracted; slight deafness,
visual disturbances and speech slurring
were found in some cases, and some
times mental confusion persisted fol
weeks.
Victims Die.
Both diseases caused some delirium
but in spotted fever this was longer
and more violent. Only the spotted
fever patients sank into comas. Near
ly one-fourth of the victims died. In
all, SO cases from the six States were
placed in this group.
k.,,NE Go he
most part were sporadic and widely sep
were grouped in areas from to 20
miles in diameter. This area distribu-
ton also Is characteristic of the dis
ease in the Rocky Mountains.
In the spotted fever group q definite
history Of tick bite within three weeks
prior to the onset was obtained in AZ
per cent Of the cases. Six per cent of
the victims remembered crushing fleas
removed from dogs. Sixteen per cent
had been bitten by chiggers, bedbugs
and various unidentified insects. The
seasonal distribution correspondent with
the duration OF the tick season and
roughly with the relative prevalence OF
ticks.
Thus far, however. the Public Health
investigators were only on the trail
The convincing evidence for the dag
nosiS was obtained by securing three
strains Of the virus from three cases
which showed the spotted fever symp-
toms, in Northern Virginia, and by
keeping these strains alive in guinea
pigs. Tested out on guinea pigs, mon
keys and rabbits, these virus strains
did not give the same reactions as
either endemic or Old World typhus
strain.
Like Montana Virus.
There was a closer correspondence
with the spotted fever virus obtained
from the Bitterroot Valley In Montana
The reactions of the guinea pigs TO
the latter, however, were considerably
| more severe. The Virginia virus strains
did not produce as high a death rate
nor did they show some of the charac-
teriStic signs. The differences were sc
| marked that 1t was evident that the
Virginia strain was not identical with
| the Bitterroot Valley strain, although
probably OF the same family.
Further evidence was secured from
cross immunization. Guinea pigs re-
covered from the Virginia virus in
noculations were immune to the Bitter
root Valley virus. No immunity was
established to tpllus. The evidence on
the whole was SO convincing that the
National Institute announced that the
Virginia strains ARE apparently closely
related to or identical with Rocky
Mountain spotted fever"
How the spotted fever virus came into
the East and the identity of its carry
ing agent remain mysteries. But hint
of what might be expected was con-
tanned in the last annual report of the
surgeon general. The range of the
spotted fever tick for years has beer
spreading out very slowly into the east
ern foothills of the Rockies. 1t is very
Only an expert can distinguish the two
Dog Tick Suspected.
Now the dog tick Is universal over the
Eastern and Central United States
Strangely enough, its range stops
abruptly. due to some subtle environ
mental effect at these same foothills
Dogs in the mountains are not infested
by ticks. But it was only a question OF
time before the ranges Of the two ticks
would cross each other.
Laboratory experiments had shown
that the spotted fever virus could be
taken over and carried by the dog tick
They way was open for the spotted fever
virus to come into the East, but it was
thought that this would require a long
time. 1t has come, apparently jumping
denness, II the virus strains found in
Virginia are derived from the Rocky
Mountain type. There is no certainty
that they may not be Of independent
origin
Through the very nature Of its trans
mission, spotted fever is disease OF
the countryside. 1t Is not transmiSSible
from human to human, but is con-
tracted only from the bite Of a tick
This tick spends the first part of its
life cycle on rodents, such as rabbits
and ground squirrels, in whose blood
the virus remains alive.
From these it falls on vegetation only
from which, in order to keep alive, 1t
gets on the bodies of the larger NAM
mails including man. Man is not a
favorite host, but is always in danger of
getting the ticks on his body when pass
ing through vegetation. The virus does
not cause sickness in animals other
than man. A somewhat similar life
cycle probably Is gone through by the
dog tick, of which little is known.
The study which resulted in the dis
covery of the spotted fever invasion was
conducted by Asst. Surgs F. F. Badger
and A. S. Rumreich and Surg. r. E.
Dyer of the United States Public Health
Service.
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