Evening star., 1948-05-10
Marshall Tells
Doctors Tropics
seCha||enge
Secretary Addresses
international Session
On Equotoriol Disease
BY Thomas R. Henry
Science Editor Of The Stor

half the human race now living
In tropical countries is an inter
national problem of first magnitude
Secretary of State Marshall tolc
delegates at the opening session
of the Fourth International Con-
crosses on Tropical Medicine ane
Malaria at the Departmental Audi
torium this morning.
The congresses, to which 60 Ma
tions were invited, are meeting fol
the first time since 1888 to consider
the new medical problems of tropi'
cal life which have arisen as ar
aftermath of the war and the re-
cent advances toward their solution
THE conquest of diseases which
hold millions weak and inefficient
the maximum production OF fooe
stuffs on lands now yielding little
are tremendously important require
ments of the world situation" Sec
retary Marshall said. THE tropics
are the habitation of perhaps hall
the human race, but large portion
of these people lack greatly in the
advantages of modern civilization
A large factor in restricting i'm
provement in these respects is tropl-
cal disease. This situation presents
challenge that, like the Equator
cuts across national boundaries.
Split Up for Discussions.
DR.. N. H. Swellengrebel, delegate
from the Netherlands, responded
briefly to Secretary Marshalls vel
come. The congresses were called
to order by the temporary president,
Surg Gen. Leonard A. Scheele.
Following the opening plenary
session, the delegates split into
groups which will discuss various
fields of tropical medicine for the
next eight days.
One of these was told today that
tuberculosis is at least twice az
common as has been believed in the
past. This has been revealed by the
mass X-ray program in the Unltee
States during the past few years
DR.. Esmond R. Long of the Henry
Phipps Institute of Philadelphia re
ported.
20 Cases for Each Death.
It has been thought up to now
DR.. Long reported, that there were
about 10 cases of active tuberculosis
to each fatal case. 1t now appears
that there are at least 20, some witt
such mild manifestations that they
would not be reported to physician.
except for the mass X-ray studies
The large number of mild cases
which never become serious, he said
indicate that the body's capacity for
fighting the disease is greater than
had been thought.
Among the latest findings, DR..
Long said, is that of natural re-
sistance to the tubercle bacillus
which runs in families. He spoke
of the work of his associate, DR..
M. B. Lurie, who has found that
either high susceptibility of resist
ance can be bred into rabbits and
maintained generation after genera
tion.
Lessons Found in Older Persons.
In the past it has been believed
that tuberculosis rarely attacked a
person over 40 for the first time
The majority of cases occurred in
persons under this age and it was
thought that person who survived
into the fourth decade of life with
out showing any tubercular symp-
toms must have high natural
resistance.
This is another fallacy, DR.. Long
said, which has been exploded by
the mass Xray examinations
Lessons of the lungs due to the tu-
bercle bacillus are by no means
rare in older persons whose chests
show no signs of previous attack
Solution of one of the outstand.
ing problems of malaria-where the
plasmodium bug hides away fol
two weeks between the time it is in.
iected into a victim by mosquito
bite and the time it appears in the
blood-waS announced to the con-
crosses.
1t makes directly for the liver
where it rests and multiplies for its
major assault.
Monkey Is Infected.
The answer has been obtained by
DR.. R. M. Shortt, of the London
School of Hygiene and Tropical
Medicine. He first infected 500 mos
quitoes by letting them feed on the
blood of monkeys infected with the
parasite. Then he ground up the
whole 500 and injected them into
q malaria-free monkey, to make sure
that the animal has massive dose
After week the monkey was
killed and every bit of its body was
searched for the hiding germs. The
only place Dr. Shortt and his asso-
ciates could find them was in the
liver There, it was determined by
experiments with other monkeys,
they remain for about 10 days get
ting accustomed to their new en-
vironment.
The finding is of special signifi-
cance. it was reported because 1t
throws light on malaria relapses
Victims often suffer attacks year
after year after a single infection.
Between attacks the plasmodia are
not in the blood stream. DR.. Shortt S
report makes it highly probable that
they lay over in the liver through
the winter months, like alternating
animals.
Determination of two distinct
types of malaria was reported. Ever
since troops started returning from
the South Pacific malaria relapses
have not followed the pattern ex-
pected in this country. They have
sometimes followed each other in
rapid succession, whereas the dis
ease with which American physi-
clans are familiar has dormant
periods of from six months to a
year.
Two Strains Used.
DR.. G. Robert Coatney and w
Clark Cooper of the National Insti.
tute of Health told of experiment.
with human volunteers using &
strain of the malaria plasmodium
the organism causing the disease
from the blood of g soldier JUS
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