Evening star. [volume] (Washington, D.C.) 1854-1972, 1955-04-08
Yellow Fever Mosquito
Wave Is Nearing U. S.
MoIody Sureing North
300 Miles South of Texas

Molody Sureing North
300 Miles South of Texas
BY THOMAS r. HENRY
PANAMA CITY.-The "blue mosque
to-" carrier of the ACKNOWLEDGEMENTS
jungle yellow fever. now is within about
800 miles of the United States.
Specimens recently have been COLI
lected, according to scientists Of the
Gorgas Memorial Laboratory here. In
the Mexican state of Taumalipas. which
borders on part Of Texas.
It also has been found that the dis
ease is carried by another mosquito, OF
the same general family as the aedes
Egyptae which carries malaria and
ordinary yellow fever. It lives close to
the ground and thus Is more seri-
Gus menace to man.
The blue mosquito itself is q dweller
almost exclusively In high treetops. It
transmits the disease. actually indis-
tinguishable from and Just as fatal as
classical yellow fever, chiefly to treetop
monkeys and possibly opossums. AS 1t
moves northward it causes enormous
fatalities among the bowler monkeys.
also almost exclusively jewellers on top
of the forest canopy, that seldom come
to the ground, and marmosets, that 60
up and down quite frequently.
Thus human beings, as long as they
stay on the ground, are relatively safe
from infection. When the malady first
was recognized in South America about
20 years ago it was called 'bride-
groom's fever" because recently mar.
ried men seemed to be the most FREE
quent victims. This was due to the
practice Of chopping down jungle trees
to make clearings for homes. The blue
mosquitoes came down with the trees.
Move Steadily North
But despite the ordinarily slim
chance that human will be bitten
there has been steady northward
progress. The disease now has appar-
emily passed over Panama to Southern
Honduras where several cases have
been detected in monkeys and there
has been one proved human fatality.
The now demonstrated fact that q
ground-dwelling mosquito also can
transmit the disease makes the threat
much more serious for countries north
of the rain forest belt.
The virus of yellow fever. it is known.
is capable Of going far north. One Of
the worst epidemics in history took
place in Philadelphia. x:
The jungle type of the disease seems
to move northward in SurgeS. Ordina-
rily when it invades an area all the
susceptible monkeys either die OF the
malady, or recover with permanent
immunity. Thus, like forest fire. the
disease constantly is burning itself out
and must wait for another generation
of susceptible individuals before It can
move forward again.
The surges apparently have urred
throughout history. Magyar priests IN
Yucatan more than 400 years ago
described highly fatal golden yellow"
disease which hit their cities at some-
what irregular intervals.
MaIady Attacked
When 1t was demonstrated shortly
after the Spanish american War that
the germ of yellow fever was trans
mitted only by mosquito bites, final
conquest of the dreaded malady seemed
at hand. 1t was necessary only to
eliminate the breeding places of the
insects near human habitations. This
discovery made the once dreaded
tropics fairly healthful. Rigid sanitary
measures. for example. made possible
the building Of the Panama Canal.
But the fact that the virus could
be transmitted by the blue mosquito
greatly complicated the problem. It
was virtually impossible to reach its
habitat in the top of the rain forest,
100 or more feet above the earth, with
any thorough eradication measures.
It was hoped that the progress would
be stopped with the end of the green
canopy.
Gorgas Laboratory scientists are
making an intensive study Of the life
habits of the elusive insect and are
especially interested in the mechanism
by which the virus is preserved during
the dry season when the mosquitoes
are quiescent. A new outbreak of the
disease always is expected with The
start Of the rainy season.
The fact that the blue mosquito now
has come so close to the United States
border is not necessarily alarming, they
say. There is no certain evidence that
the individuals found in northern Mex.
leo actually are disease carriers. But,
the Gorgas scientists insist, they must
be considered warning against COM
placency.