INTRODUCTORY REVIEW
   A New Quadrennium

The Role of PASB

During 1955 the Pan American Sanitary Bureau (PASB)
continued to fulfill its long-established role of cooperating
with governments throughout the Americas in helping "to com-
bat disease, lengthen life, and promote the physical and
mental health of the people." Headquarters are in Wash-
ington, D.C., but zone and field offices reaching out deeply
southward have for some years now been established in
Mexico City, Guatemala, Kingston, Lima, Rio de Janeiro
and Buenos Aires. Government health programs, with the
PASB cooperating directly through the zone offices, have
increased in scope and influence. This is in accordance with
a plan of PASB  d ecentralization, now in full operation
for some four years.

The Pan American Sanitary Bureau is an international
public health organization created and maintained by the
Republics of America.  It is the oldest international health
body in the world. It was organized by the First Pan
American Sanitary Conference in 1902.

The functions of the Bureau are defined by the Pan Amer-
ican Sanitary Code (1924), a treaty ratified by all 21 Re-
,publics. Article LV of this Code makes the Pan American
Sanitary Bureau a central coordinating agency with an almost
bewildering variety of duties, all relating to health.

As the 1924 Code provides, the Bureau is to appoint
representatives to confer with the health authorities of the
various signatory Governments; to receive, publish and dis-
tribute information on vital statistics, public health organ-
ization, preventive medicine, and other pertinent information;
to undertake cooperative epidemiological studies; to stimulate
and facilitate scientific research; to bring about exchanges of
professors, medical and health officers, experts, and advisers
in public health; and to provide technical information relative
to the actual status of communicable diseases, progress ef-
fected in the control or eradication of such diseases, and
new methods for combating diseases. All of these things
almost without exception, the Bureau has been doing to
this day.
In 1947, the Twelfth Pan American Sanitary Conference,
at Caracas, established the bases for the Constitution of the
Pan American Sanitary Organization (PASO) and the con-
ditions for negotiating an agreement with the World Health
Organization (WHO). The rapid expansion of the Bureau

to its present .size has taken place chiefly in the last eight
years.

By the Agreement (May 24, 1949) between the two organ-
izations, PASB functions also as the Regional Office for the
Americas of WHO. In this Report, for the sake of simplicity,
the term Bureau or PASB will be used to mean the Pan
American Sanitary Bureau, Regional Office of the World
Health Organization.

In carrying out its tasks, PASB works in close harmony
with a number of other organizations, including the United
Nations International Children's Fund (UNICEF), the In-
ternational Cooperation Administration (ICA) , the Food
and Agriculture Organization (FAO) , and the Organization
of American States (OAS) .

By the Agreement (May 23, 1950) between the Council
of the Organization of American States and the Directing
Council of the Pan American Sanitary Organization, the
latter is recognized as an Inter-American Specialized Organ-
ization in the field of public health.

Cooperation with closely associated international organ-
izations will often, but may not in every case, be specifically
acknowledged in this Report.

In the next section brief mention is made of highlights as
to budget and program. A more detailed picture of sources
of funds and interrelationships of activities with other
organizations is given in a later section of this Report.
(See page 128)

Budget and Program

The regular funds of the Bureau consist of annual PASO
quota contributions from the twenty-one American Republics
and from France, the Netherlands and the United Kingdom,
plus a share of funds raised by WHO by similar contributions
from WHO Member Governments. The Bureau gives tech-
nical supervision to many programs receiving United Nations
Technical Assistance (UN/TA) funds and participates in the
OAS Technical Cooperation Program receiving OAS/TA
funds. Expenditures of the PASB in 1955 amounted to
$4,547,277.65 of which roughly three million dollars came
from regular PASBWHO funds and the remainder from
Technical Assistance or Extra Budgetary funds. In 1955 an
additional amount of $3,156,294.45 in equipment and sup-
plies was made available to Governments by UNICEF for
projects in which PASBWHO participated.

1


One objective of the Bureau is to develop national programs
carried out under government auspices. The Bureau always
operates on invitation by governments and in collaboration
with governments. It does not have working forces of its
own which can go into the field and carry out campaigns
against diseases. It does have a corps of experts and con-
sultants, who help to strengthen the health departments of
governments through cooperation, aid in planning, and pro-
vision of technical assistance. The Bureau also acts in general
as a clearing house for scientific enlightenment aiming to see
to it that in matters of medical and public health knowledge
all nations of the Americas will share and share alike.

It also helps by providing opportunities for training. This
training on all levels, includes in its scope medical men,
engineers, nurses, nursing auxiliaries, sanitary inspectors,
and other health workers of various categories. The aim is to
make such training, given either within or outside of the
country, part of a thoroughly planned and consistently
executed program. Each year several hundred selected workers,
many of whom will occupy strategic posts in health work or
health education, are thus given the opportunity to acquire
the training which can make their work effective.

Other aspects of this educational program are taken care
of by the conferences and seminars and by the variety of pub-
lications sponsored by the Bureau.

Since the Bureau was firmly established on a broad Pan
American basis its specific health programs have grown in
scope and in direction. By growth in direction is meant that
at approximately quadrennial intervals the goals of these )
programs are reexamined and made more specific by the Pan
American Sanitary Conference, the supreme governing body
of the Bureau.

The latest appraisal of this sort took place just before the
beginning of 1.955 at the Fourteenth Pan American Sanitary
Conference held in Santiago, Chile, October 7-22, 1954. Dur-
ing the busy weeks of this gathering there was hammered
out a program the nature of which comes out unmistakably
in the major resolutions taken.

These resolutions which go into considerable detail cover
five main points: 1) better health statistics, 2) a determined
attack on infant diarrheas, 3) improved environmental sanita-
tion, 4) continuation of the strong initial successes against
trcponematoses, 5) and as a crowning effort the carrying
forward to completion  of malaria eradication from the
Americas.

Malaria Eradication

Much will be said about malaria eradication both in this
Introduction and also later on in the body of the Report,
because a substantial part of the PASB effort in 1955 went
into the planning, launching, and forward projection of a
hemispheric malaria eradication program. During this year
a special office, known as the Coordination Office of the
iMalaria Eradication Program (COMEP), with its initial
location in Mexico City, was set up as an integral part of the
PASB. During this year also Mexico announced a Q20,000,000
malaria eradication campaign to extend over four years. Be-
cause of the size and importance of the malaria eradication
effort in Mexico that country was chosen as headquarters for
COMEP which, however, also serves the whole of the Amer-
icas. With the campaign in Mexico firmly launched, the past
year has witnessed the spearheading of a movement that
should eradicate malaria from the Americas.

It was heartening when the largest nation in America
achieved success in its malaria eradication program just a
few years ago. The U.S. Public Health Service followed up
its World War II anti-malaria activities with the National
Malaria Eradication Program. This was inaugurated in 1945,
with the cooperation of certain state and local health agencies.
Eradication operations reached their peak in 1948 when

2

1,365,000 homes in 13 States were sprayed at a cost of
$~,OOO,OOO, following which it became possible to curtail
operations each year until 1952, when less than 100,000
houses were sprayed. For several years the cases of indigenous
malaria occurring in the U.S.A. have been secondary to im-
ported malaria from Mexico or from the Pacific. Only 46
such cases were found in the U.S.A. during 1954 and none,
establi,shed as indigenous, was reported in 1955.

Theoretically malaria can be eradicated from a given area
in three years by a method which is now beginning to be well
understood. In the absence of reinfection the malaria
organism usually disappears from the human host within
three years, but on national eradication programs allowance
must be made for delays in development of training of staff
as well as possible administrative inexperience. Malaria is
transmitted by various species of Anopheles mosquitoes, but
the species most dangerous as vectors of malaria are those
which enter human habitations in search of human beings to
feed upon. Since Anopheles usuaIly rests on waIIs before or
after sucking blood, putting a powerful insecticide, DDT, on
these walls is effective in eliminating the infective mosquito.
More details on how and why this happens will be given
later on. Thus transmission of malaria is stopped by a chemi-


cal attack on mosquitoes which enter the home. This ingenious
solution, which limits antimosquito measures to the home,
is a great improvement over antilarval measures, which had
to be applied to extensive ground-breeding areas.
The new method of malaria eradication has brought about
some surprising changes in method. Nowadays malaria work
should be measured not by what has been done but by what
remains to be done. It used to be that if a disease was 80 per
cent conquered everyone felt happy, but now in malaria at least
alI eyes are centered on the last remaining cases. The work left
to be done used to be measured by the prevalence of mosquito
larvae. Now it is measured by the number of houses in
which infected persons live.

       The Seriousness of Malaria
The tremendous cost and the tough perseverance needed
to rout out the remnants of malaria from this hemisphere is
put into the right perspective, if it is remembered that
malaria in its malignant form is a highly fatal disease. Histori-
cally its main ravages have been among the young.  It is still
one of the world's great killers of children.
Malaria as it was unchecked before the days of quinine
and modern medication, has wiped out civilizations, and given
back straight to the jungle large areas of inhabited land.
Malaria can be a scourge of nations and a crippler of indi-
viduals. Populations, where malaria is chronic, drag along on
a bare subsistence level. Even when it is present with a rela-
tively low infection, malaria inhibits to a surprising degree
both mental and physica effort.

The Magic of DDT

No wonder that centuries ago, first cinchona bark and then
its alkaloid derivative, quinine, was hailed as a sovereign
remedy. Quinine does not cure malaria infection but it does
cure the attack of chills and fever leaving, however, a seed bed
to produce a later attack. Late in the last century the connec-
tion between the mosquito and malaria slowly came to light.
Then in the first half of the present century an enormously
varied general attack against mosquitoes has helped to keep
down malaria, but neither drainage nor screening nor dusting
with Paris green nor the use of fish to eat mosquito larvae
are anywhere near efficacious enough to finish the job largely
because if thoroughly done they are too expensive. lt wasn't
until the introduction of DDT as a residual insecticide that
economically feasible measures for the control of rural malaria
became possible. All this has happened practically within the
last decade.

The Economic Damage of Malaria
In addition to being a potential killer malaria robs a nation
Of its economic strength. Malaria degrades and enslaves. No
infected area can compete in agriculture or industry with a
"On-malarious region. Malaria cuts labor efficiency down by
half or more.

Less than 30 years ago the estimated annual cost of malaria
to southeastern United States was over $500,000,000. Today
industry is expanding in a11 of those states from which malaria
was banished. After World War II malaria control in Greece
in a single year augmented the labor effort by thirty million
man days. In Burma and in Pakistan rice production in-
creased 15 per cent within the first year after malaria was con-
trolied. In Iran with malaria kept down, four laborers in rice
harvesting could do the work of ten. It is because it makes
possible these great savings that malaria eradication has come
to be considered a good investment.
This is not to say that malaria eradication is cheap. It is
expensive. It involves a large capital expenditure. But it stil1
pays off handsomely, especially in the long run.

Impact of DDT

During a full half century after discovering that malaria
is a mosquito-borne disease, and until only a short decade
ago, malaria was the most difficult problem facing public
health workers in the tropics and sub-tropics, and in many
parts of the temperate zones. Previous to the introduction of
DDT as a residual insecticide, economically feasible measures
for the control of rural malaria were not known. The initial
results of this new measure have been dramatic.
The introduction of DDT has halted expensive drainage
works as we11 as costly larviciding operations, and has led to
the control of malaria in many agricultural areas, where the
isolation of dwellings one from another makes other methods
of control impractical. Thus the road was cleared to the
development of nation-wide control programs. These in turn
led to the most promising observation that malaria, as a
mosquito-borne disease, disappears from an infected popula-
tion within a few years after transmission ceases. The further
observation has been made that malaria reappears in cleared
areas only when reintroduced by an infectious person from
an endemic zone. The United States, for example, parts of
which were previously highly malarious, has been free of
epidemics of malaria for a decade except for a small out-
break of 35 cases infected in 1952 by mosquitoes which
had fed on a returned veteran from Korea.
By 1950 nearly a11 countries in this hemisphere with a
malaria problem were engaged in serious efforts to control
it. Malaria was eradicated from Chile, French Guiana, Puerto
Rico and the United States, and nearly gone from Argentina,
British Guiana and Venezuela. Control programs were well
advanced in most of the other American countries. So rapidly
had programs expanded that approximately 75 per cent of the
total homes in the malarious zones of the Americas were
sprayed that year. It was hoped that the remaining 25 per
cent (four and one-half million homes) would soon be
brought into the program.

TO stimulate further progress and boldly aiming at eradi-
cating the disease from the Western Hemisphere, the


MALARIA ERADICATION-WESTERN HEMISPHERE
       SUMMARY OF COSTS

120-

110-

loo-

90-

SO-

30-

20-

lo-

O-

-$1 13,885,OOO
-$112,385,000

-$ 96,300,OOO

-$ 75,465,OOO

-$ 65,932,OOO

-$ 51,230,OOO

$ 1,500,000


$16,085,000

Contribution of WHO/PASB 6

Additional contributions required from UNICEF or
other agencies s

$20,835,000

Additional expenditures required from Governments (with
exception of El Salvador, Haiti and Mexico)l

s 9,533,ooo     UNICEF commitments for El Salvador, Haiti and Mexico 3

$14,702,000

Actual budgets of El Salvador, Haiti and Mexico during
5 years of eradication s

$51,230,000

Actual expenditures of countries, projected for a J-year
period (with exception of El Salvador, Haiti and
Mexico) i

EXPLANATION OF COSTS

I Based upon actual expenditures of all Governments (except El Salvador, Haiti and Mexico), projected over a 5-year period.
`Actual commitments of El Salvador, Haiti and Mexico for S-year programs of eradication.
3 UNICEF commitments to El Salvador, Haiti and Mexico for 5-year programs of eradication.
* Based upon labor and administrative costs for additional houses which must be sprayed by all Governments (except El Salvador,
Haiti and Mexico), for 5 years to achieve eradication.

' Based upon supply requirements of US0 0.50 per spraying, for additional houses which must be sprayed for 5 years, to achieve eradication.
' Based upon personnel required by COMEP, plus 20 consultants to countries.           

5


Thirteenth Pan American Sanitary Conference (1950) recom-
mended that the PASB coordinate anti-malaria programs of
individual countries.

Campaigns were expanded by Governments, as trained
technicians became available in countries, and equipment and
materials were supplied by UNICEF to the Caribbean and
Central American area and four South American countries.
Malaria control campaigns were initiated in every malarious
country of the hemisphere. The disease toppled from its
position as the leading public health problem in the Americas.
Hopes were high and the enthusiasm of the average house-
holder for the method appeared to ensure success of the eradi-
cation program.

DDT Resistant Anopheles

But success was not to come so easily. Unfortunately, the
house fly, which was the householder's visible measure of the
value of any insecticide, developed a marked resistance to DDT,
and the residual spray program lost much of its initial pres-
tige. The publicity given to the rapid reduction in malaria
following the introduction of residual spraying, resulted in
the general conviction that malaria is no longer an important
problem and can safely be disregarded.

Instead of rapidly increasing appropriations, a lag set in and
four years later, 1954, 22 per cent of the homes in malarious
areas still were not included in control programs. Authorities
reacted to other fiscal pressures and reluctantly appropriated
funds for controlling a disease which seemed to cause but little

MALARIOUS AREAS IN THE WESTERN HEMISPHERE PREVIOUS TO WORLD WAR II

damage. This situation, disappointing as it was, might have
been gradually improved from year to year in individual
countries as opportunity appeared, had it not been for the
threat inherent in the recent development of resistance to DDT
by certain Anopheles.

In Greece, the three local vectors have developed resistance
and DDT is no longer effective in controlling malaria in some
villages. Another important malaria vector has become resistant
in Indonesia. In Central America one of the principal mosquito
vectors is exhibiting a changed behavior to the insecticide,
a change which may presage the development of resistance.

Urgency of Eradication

It is most unfortunate that resistance is developing before
malaria has been eradicated, since the pre-DDT control
methods are too expensive for general use in rural areas. It
is obvious that malaria must be eradicated from the Americas
before the threat of anopheline resistance to the insecticide
materializes here.

The Fourteenth Pan American Sanitary Conference (Oc-
tober 1954) recognized the danger of prolonged control pro-
grams. The Conference bespoke the utmost urgency in achiev-
ing the continental eradication of malaria and urged the
Member Governments immediately to convert all control
programs into eradication campaigns.

Extra effort applied now makes the difference between
success and failure. A few years of all-out drive can so reduce
the amount of malaria that residual pockets may thereafter
be eradicated with newly available drugs, if necessary. When
malaria has disappeared, surveillance or vigilance squads
can ensure continued freedom from the disease at a low and
entirely feasible cost.

The full promise of eradiction for the continent depends
obviously on the simultaneous. wiping out of malaria infec-
tion from all countries in the Americas. Once this is done,
expenditures can be greatly reduced and vigilance relaxed
except against reinfection through immigrants or travellers
from other parts of the world.

If one laggard state, in order to reduce expenditure, fails
to destroy all of its malaria, that state becomes a menace to
its neighbor. Its hidden sparks may start new fires. Complete
control for at least three years is necessary, because then in
the absence of reinfection, malaria parasites will die out.

Conversion from Control to Eradication

Eradication depends on action at the national level. Each
nation, as a member of PASB/WHO automatically has under-
taken an obligation to all the other countries, as well as to its
own population, for execution of an eradication program.
Action in all countries should proceed simultaneously.
Inasmuch as conditions and the extent of existing control
measures vary from country to country, a new plan is being

6


-

Item

.

Control

-

1. Objectives
2. Area of operation

Reduce the disease
Start where the disease is worst and does

most damage

;. Work of standards
4. Duration of work

Good work acceptable
No end in sight. Campaign may go on

forever

5. Residual malaria            Of little interest
6. Economic aspect         Spray within budget
7. Other insects          May be considered as part of the anti-

8. Notification of malaria cases
9. Participation of other health serv-
ices

malaria program
Of secondary value
Not really necessary

10. Other professional assistance
11. Suspicious cases
12. Imported cases
13. Epidemiological survey
14. Administrative evaluation of prog-
   ress
15. Epidemiological evaluation

No special interest
Not important
Academic interest
Expensive and useless
Measurement of what has been done

Reduction of spleen and parasitological
indices

MALARM ERADICATION VERSUS CONTROL

Eradication

Eliminate the disease
Every place where transmission occurs is

important

Perfection required
Definite terminus, 3 years after transmis-

sion stops

Of prime importance
Pay extra, but spray
Not to be considered except for Aides

aegypti

`Of prime importance
Fundamental to help recognize cases of

malaria

Needed for prompt notification of cases
Of prime importance
Crucial after spraying has been suspended
Indispensable. The key to eradication
Measurement of what remains to be done

Disappearance of endemic cases

made in each case covering the details of an eradication pro-
gram. This plan provides for a unified country-wide service,
operated according to international technical standards with
uniform reporting procedures to facilitate international CO-
ordination and analysis.

Careful training of eradication staffs imbuing them with
the philosophy of eradication, and then tight administration of
the eradication work through three or more years are necessary
to insure that malaria will die out of the entire human pop-
lation of the area covered. Taking into consideration the
recruitment and training period and the progressive nature of
the organization of control measures, it is probable that the
manpower, transportation, and supply requirements will be
spread over a period somewhat longer than three years.
' Large scale and continuous blood tests for the presence
of malaria are an essential part of an eradication program.
This is needed to check on the efficacy of the method and the
efficiency of its application, and to signal the time when eradi-
Lation has been achieved so that the costly insecticiding oper-
`ations can be stopped. Surveillance must be continued long
after the antimosquito measures are discontinued in an area,
ihd if any focus of infection is found, appropriate measures
inust he instituted immediately.

MALARIA ERADICATION IN
    DECEMBER 1955

THE

WESTERN

7


STATUS OF THE ANTIMALARIA CAMPAIGN, 31 DECEMBER 1955

COUNTRIES

ARGENTINA

BOLIVIA

BRAZIL

CANADA

COLOMBIA

COSTA RICA

CUBA

CHILE

DOMINICAN REP.

ECUADOR

EL SALVADOR

GUATEMALA

HAITI

HONDURAS

MEXICO

NICARAGUA

PANAMA

PARAGUAY

PERU

UNITED STATES

URUGUAY

VENEZUELA

8


FRENCH GUIANA

GUADELOUPE

MARTINIQUE

ST. PIERRE AND MlOUELON

NETH. ANTILLES(ARUBA
BONAIRE CURACAO SABA
ST. EUST6;TIUS, ST. Fn~RTifi
SURINAM

BAHAMAS

BERMUDA

BRITISH GUIANA

BRITISH HONDURAS

CAYMANS,CAICOS,TURKS

COLONY OF WINDWARD ISLANDS

GRENADA- CARRIACOU

TOBAGO

TRINIDAD

JAMAICA

ALASKA

PANAMA CANAL ZONE

PUERTO RICO

U.S. VIRGIN' ISLANDS         . . . . . . . . . . . . . . . . . .
                          . . . . . . . . . . . . . . . . . .
                           . . . . . . . ..*........
                          . . . . . . . . . . . . . . . . . .


Scope of DDT Campaigns

Yellow Fever Mosquito Included

Both yellow fever and malaria are carried by mosquitoes.
It seems natural that campaigns against them can be com-
bined. In the very early days, shortly after 1900, this was
done by General Gorgas in Havana. However, A?des
"egypti breeds in the artificial water containers found around
human habitations. It is a domestic mosquito, although found
also in the houses of some rural areas, whereas the Anopbeles
or malaria mosquito is distinctively wild. House spraying for
malaria, will eradicate Aides aegypti but a program aimed
solely at Ai;des negypti does not contribute to malaria eradi-
cation.

To destroy the AZdes aegypti mosquito one has to spray
DDT only in and around the breeding places of the mosquito,
but to control Auopheles mosquitoes it is usually essential to
spray the entire inside walls of all the houses.

It may be asked, how does this affect the rural Auopheles
mosquitoes which breed out in the fields or swamps. The
answer, as partially explained above, is that the Auopbeles is
a night biter. Along about dusk it flies in from the fields in
search of human beings to bite. Along about this time too
men are returning to their homes. Although the Afzopheles
is not a house breeding mosquito, it goes on long flights in
search of its human victims who do live in houses.  When


the mosquito reaches a house it takes a rest first on the walls.
In biting its victim the mosquito makes a thorough job of it
either at one long feeding or a number of short ones. In
either case the proboscis goes way in and the process of
pumping up blood takes some time because it is at the same
time a filtering process. The mosquito passes through its
body immediately the serum or colorless part of the blood.
It is after the red blood cells.  If normal blood has a certain
concentration of red blood corpuscles per unit, the blood inside
the mosquito has three times as much. In other words, the
mosquito is filtering out the colorless blood serum.  It also
takes on such a heavy load of blood that its abdomen visibly

extends. When it flies away with its load the course is a
zig-zag one, and again as soon as possible the Insect seeks a
wall on which to rest and continue the filtering process or the
discharge of the serum.

The wall which has been sprayed with DDT is therefore
to all intents and purposes a trap, and a good trap because
there are three chances to get the mosquito: 1) when it first
comes into the house tired from its long flight, 2) after it
has bitten the human being, taken on a load of blood, and
again seeks the wall, 3) some days later when it may return
for another blood meal and once more rest on the wall before
or after biting.

11


A mosquito is not dangerous immediately after biting.
There is an incubation period of about two weeks before the
Atzopheles can infect a new victim.  However before this
happens there are as we have seen, at least three chances that
the insect will have lighted on a wall and been destroyed.
It is necessary to understand this mechanism of malaria trans-
mission in order to see why malaria campaigns based merely
on house spraying can be effective.

One additional fact should be kept in mind. The most
malignant malaria organism, Plasmodhn fddpnum, does not
generally live over one year in the human body unless re-
plenished; the other more common malaria producing organ-
ism, P. vivax, seldom lives longer than two and one-half years,
and the third P. nzalariae may live longer, but it produces a
few cases that can be ignored until the others are eliminated,
and then be eradicated as each case is found during surveil-
lance, and effectively treated by chemotherapy. Generally
within three years the malaria organism should die out in
human beings if mosquitoes are not there to keep up the
supply of parasites. Keep the Anopheles under tight control
for three years and the human population can no longer
infect them.

This will be the case unless after stopping control measures,
malaria is reintroduced by people from the outside.  Hence
malaria eradication must keep on taking in new territory.
As soon as one area is cleared the work should be extended to
the border areas. Nothing is more logical than that after a
few countries in the Americas had banished malaria the work
should be extended to all the countries in the Hemisphere.
Then after the Americas, the World. There is in the nature
of an eradication program a drive toward universality.

How Yellow Fever Travels

The reason for getting rid of Addes aegypti everywhere,
even in countries which never had yellow fever, is that that
mosquito makes the country receptive to a very serious
pestilential disease.  Jungle yellow fever is transmitted to
man in the forest by one or another of several different species
of wild mosquitoes. Urban yellow fever is the very same
disease transmitted from man to man by AZdes aegypti, a
domestic mosquito of towns and cities, and certain rural areas.
When yellow fever virus gets into a tropical city with lots of
aegypti and lots of susceptible people, a great many people
get infected and a severe epidemic may occur.

Jungle yellow fever is not transmitted from man to man.
The infected mosquitoes which bite man in the forest and
infect him get their virus from monkeys or from some other
forest vertebrates-not man. This is important because forest
animals-including man when he is in the forest-travel
rather slowly through the forest.

Nowadays it is possible for an infected man to get on an
airplane and fly almost anywhere in the world within the
incubation period of yellow fever.  Formerly, he got on a
train, or, for longer distances, on a boat.  Whatever the

12

means of travel, man obviously is the vehicle which yellow fever
virus uses for rapid dissemination over long distances.

The last fatal case of yellow fever in the United States
occurred in October 1924 when a Mexican immigrant died in
Houston, Texas. He had arrived in the United States a few
days before by ship from Progreso, the-principal port of the
Yucatan Peninsula in Mexico, just across the Gulf of Mexico
trom New Orleans, where he had disembarked. He went to
Houston by train. The same travel route is used today, but the
time needed is measured in hours instead of days.

In 1924 Ai;des aeg)pti was present in Progreso, in Merida,
in New Orleans, and in Houston.  The mosquito is still
present in all those places today.  This makes all these places
receptive to yellow fever. The entire coast of the Gulf of
Mexico is infested with AHdes aegypti, both in Mexico and in
the United States. In fact, thirteen states of the United States
of America are infested with aegypti. The eradication of
aegypti from all this large area would be a large and expensive
task, but it would be very much worth while, for it would be
a definitive solution.

Somebody asks, "Why not vaccinate everybody in the
threatened area against yellow fever? Would that not remove
all danger ?"  The population of the 13 southeastern states
which are infested with AZdes aegypti is about 39,000,OOO.
Many millions more live in the infested portions of Mexico.
To vact'inate all these people would be a large task, difficult
if not impossible to perform perfectly, and one which would
have to be repeated every six years, according to present
practices.

On the other hand, if Al;des aegypti were eradicated from
the infested region, the threat of yellow fever would be
removed once and for all, because the mosquito needed to
transmit it would not be present. Once the United States has
eradicated its aegypti there is little danger that the mosquito
would be reintroduced from the few remaining places where
it is present in the Americas.

Endemic Yellow Fever Areas

A clear distinction must be drawn between the eradication
of A.?des aegypti and the eradiction of yellow fever. The
former is possible and desirable; the latter is impossible. The
mosquito can be eradicated from large areas, if not perhaps
from everywhere; the jungle form of the disease cannot, with
means now at our disposal, be eradicated from its jungle
refuges in the tropical rain forests of the Congo Basin in
Africa and the Amazon Valley in South America.  At best the
disease can be prevented if everybody who goes into those
areas, and also into the forests near these areas, is vaccinated,
but the virus which causes the disease in man has an extra-
human reservoir, and thus can survive quite independently
of man.

Jungle yellow fever is, therefore, a zoonosis-meaning a
disease of animals transmissible to man. This zoonosis may


be either enzootic or epizootic. The variety of-ways in which   Philippines, and many neighboring countries are all receptive
yellow fever virus manifests itself, in Africa and in the   to yellow fever, according to the definition used in this Report.
Americas- but not in Asia-is very great. The very fact that
yellow fever has never occurred in tropical Asia, where   Epidemic Irruptions
conditions seem ideal for it is one of the enduring riddles    It is perhaps salubrious to recall that the jungle type of
of modern medicine.                   yellow fever was first recognized only 24 years ago, in 1932.
This is not the place to discuss this riddle, but it is the   It is well to be on guard in drawing conclusions because there
pl:lce to stress the fact that India, Malaya, Indonesia, the    is still a lot to learn about the matter.


A case in point is the epidemic of jungle yellow fever
which began in Panama in November 1948 and spread slowly
and jerkily westward and northward through Middle America
until it reached northern Honduras in September 1954. There
had been no yellow fever for nearly 30 years in this area.
The fantastic way in which howler and spider monkeys died
of yellow fever during the recent epizootic was noted in the
Annual Report for 1954.

Greatly to everybody's surprise the entire year of 1955
went by without a single case of human yellow fever having
been diagnosed anywhere in Middle America, or even a
single positive monkey having been found.  It looked as if

the epidemic had died out at about the northern limit of the
range of the forest mosquito, Hae?Jzagogus spegazzjrzii faho?
This well-known mosquito was associated with yellow fever
in monkeys everywhere to the south and east in Central
America.

The need for patience was exemplified by the finding:
early in 1956, that the virus had done two surprising things.
It had not died out in Honduras but in fact had spread on
into Guatemala, reaching a point only 110 miles from the
nearest point on the Mexican border.  Ahead of it were
generous tropical rain forests inviting it to come on into the
Mexican States of Chiapas, Tabasco, and Vera Cruz. The


second thing was even more startling, because it was unique:
the virus had remained present for 21 months in one small
area of coastal forest in northern Honduras, where there were
        . . .
no spegazzmn.

In the main section of this Report there are presented
data in the way of maps and accounts of present anti-AgdeJ
negypti campaigns in which the PASB is cooperating.
During 1955, Mexico unfortunately interrupted the aegypti
eradication program which had begun to take shape in
Yucatan, but with the observation of yellow fever in monkeys
in Guatemala, this campaign is to be renewed.

The USPHS is investigating the Addes aegypti situation in
ports and coastal areas. There is as noted above every reason
why the United States should join hands with the rest of the
Continent in disposing once and for all of the potentia1 threat
of urban yellow fever.

Both the conquest of malaria and the control of yellow
fever call for eradication techniques. And this is not the
whole story of eradication. The eradication concept has an
even wider bearing. It now appears that a number of dis-
eases, wideIy dissimiIar in modes of transmission can best be
combated by ever-expanding eradiction campaigns.

Conquest of Treponematoses

The Extension of Eradication Techniques

In setting up the campaigns for malaria eradication in
various countries of this Hempishere, a great deal of study
was given to strategy and methods of training.  On an adjoin-
ing page is given a table displaying the contrast in attitude
between the methods of a campaign aiming at control and
a campaign aiming at eradication.  From start to finish the
attitude is different.

It is this general approach, the phiIosophy so to speak, of
combating disease, that is in this day and age undergoing a
major change. Instead of merely keeping down or holding
back disease, public health authorities are beginning to accept
the idea that disease should be exterminated.  It is cheaper
and better to do away with specific infections altogether than
to keep them around even at the reduced and almost harmless
level from which at any time they might again flare up.

This attitude is well illustrated by the new style campaigns
agatnst yaws, one of which is nearing completion in Haitr.

Successful Yaws Campaign
AS Treporzerna palfida, a spirochete, is the cause of syphilis
SO Trepolzema perte)tne, morphologically indistinguishable
from T. pallida, causes yaws,  Yaws or frambesia, not a
venereal disease, but an infectious and disfiguring affliction
prevalent in the Caribbean area and elsewhere was in 1949 a
major public health problem in Haiti.
From reliable sources it was concluded that the prevalence
of yaws in Haiti at that time was 40 to 60 per cent.  Some
authorities claimed that 80 per cent of the rural population
was afflicted.

Of the three more common ways of organizing campaigns

against yaws, viz., 1) permanent dispensaries, 2) ambulatory
or mobile clinics, and 3) house-to-house work, only the
latter can be considered where early eradication is the objec-
tive. Experience in Haiti had shown that permanent dispen-
saries could attract only a small part of the population. The
same was found to apply to the mobile clinics. In Haiti
the only way to get full coverage was to pay a visit to every
single dwelling.

The anti-yaws campaign which began in 1950, is based
upon the use of penicillin.  A single dose of penicillin
renders a case of yaws non-infectious.  Fortunately, too,
laymen can be trained fairly easily for this work. Such
training of personnel plus the experience gained from former
A&/es aegypti campaigns has made the yaws campaign not
only a possibility but a striking success.  Close attention,
however, had to be given supervision and logistics.

With penicillin as the therapeutic agent of choice there
was started in 1950 a campaign with the single objective of
eradicating yaws.

The Government furnished personnel, fuel and lubricants
to the extent of $196,000 a year. UNICEF supplied the
penicillin, vehicles, and other necessary supplies. The Bureau
made available technical personnel to cooperate with the
Haitian Health Administration. Field operations began July
20, 1950.

The ambulatory clinic method was used July 20, 1950, to
October 26, 1951, to treat 600,000 persons mostly in south-
ern Haiti.  During the middle part of 1951 it became clear
that the method had to be changed. The house-to-house
method was made routine after October 27, 1951. Coverage
then became practically 100 per cent. It is of paramount

15


importance in a yaws campaign to treat all household contacts
as well as actual cases.

By December 1954 practically the whole population of
Haiti, 3,500,OOO persons had been treated with penicillin.
After this came the mopping-up phase. Yaws eradication has
probably been accomplished if no autochthonous case has
occurred during a one-year period. This has not yet been
ascertained but spot surveys following mass treatment showed
an over-all prevalence down to 0.57 per cent. The index
of infectious cases, called incidence ratio, was only 0.15
per cent.

The work in Haiti demonstrated that the key to eradica-
tion is close supervision. Eradication is never easy or simple.
In the words of the consultant in active charge: "It takes
means, money, time, authority and, in the tropics, sweat."

In Haiti, and in yaws campaigns in general, the use of
penicillin in amount of dosage and method of administration
is aimed directly at yaws. Indirectly a campaign of this kind,
while not at the same time eradicating syphilis, does help to
keep down and to reduce syphilis, and may therefore be
considered as a step toward the conquest of Treponematoses,
including syphilis.

Creating the New Outlook

The Goal of Zero Incidence

Disease control campaigns are by now a well established
procedure. Against certain communicable diseases, system-
atized control campaigns have been in operation ever since,
in the closing decades of the last century, the causative rela-
tion between germs and disease was discovered, and bacteri-
ology came into its own. The new outlook regarding control
campaigns is not to let them drag on, but to change them to
eradication campaigns and so bring them to an end.
In certain diseases there has been a crescendo of improve-
ments in control until finally the disease has been driven
into a corner and the end has come in sight. This is the
case with malaria which in the Western Hemisphere, as we
have seen, is now ready for the kill.
Some diseases Seem to disappear spontaneously before the
march of civilization. This promotes a feeling of security.
There is no longer the great apprehension concerning plague
or smallpox, that used to terrorize the world a hundred or
more years ago. However some real fears still remain. The
1928 influenza pandemic was a genuine disaster. The para-
lytic form of poliomyelitis is increasingly important, and hope
surged around the world when the Salk vaccine appeared.
Increasingly such communicable disease threats as these
are bringing about not fears but plans for eradication. The

eradication philosophy has made such a place for itself in
public health thinking that in certain diseases it now seems
reasonable to settle for nothing less than eradication. In
other diseases some of the techniques of eradication may be
applicable well before the end is near.
Eradication then is not merely a method applicable to a
single disease .such as malaria or even to a group of diseases;
it represents a point of view. The general effect of the ap-
plication of eradication principles is that it brings into view
a hopeful era in which more and more diseases are forced
across the goal line of zero incidence.  To think of eradica-
tion in this broad way means looking very far ahead.
In tuberculosis for the first time in history a high pro-
portion of patients can now be made non-infectious by drug
treatment. New innocuous antituberculosis drugs such as
isoniazid open the way for chemoprophylaxis. It can aheady
be said that chemotherapy undoubtedIy prolongs the life of
a number of patients.  Still to be determined is how fast
the community load of infection goes down.
It is certain that death rates from tuberculosis in many areas
of the world have in the last decade taken a sudden drop. This
is not limited to countries economically prepared to handle
the tuberculosis problem. In the United States the rate has
dropped from about 113 per 100,000 in 1920 to about 13
per 100,000 in 1953. In Chile from 1920 on the rate ran

16


about 250 and then during the 50's dropped to around 87.
Other countries echo the same story. Tuberculosis experts in
n~any parts of the world are beginning to be much more hope-
ful. An element in the new optimistic outlook is the success
of domiciliary treatment. In some localities the number of
beds available for tuberculous patients outnumber the patients.
The need for big sanatoriums is disappearing.

In tuberculosis work there is first the task of case finding,
i.e. locating persons who discharge tubercle bacilli through
the respiratory tract. Next comes the protection of healthy
people by increasing their resistance, and here WHO/UNICEF
in the Americas has cooperated extensively in the support
of BCG campaigns. Third comes the prevention of trans-
mission and here is where the new chemotherapy is making
its contribution. It helps do this even where isolation of the
patient is not practicable.

The strategy with regard to tuberculosis is changing. In-
stead of building more isolation hospitals there is emphasis
on the use of isoniazid in home treatment of recognized cases
and on the prophylactic treatment concurrently of other
people in the family with the same drug in smaller doses.
Isoniazid has the advantage of being cheap and readily manu-
factured in any desired quantity.

The broader aspect of this is that tuberculosis may join
the group of vanishing diseases.

In leprosy, too, the attitude is changing. More and more
cases are being arrested and made non-infectious.  In centers
where this disease has been a real problem there is now
anticipation that practically all lepers who come for treat-
ment will eventually be returned to normal life. The problem
then becomes one of returning these agelong outcasts to a
normal place in the social structure,  The big advance has
been in the treatment with sulfones which are not to be con-
sidered as an immediate and permanent cure, but rather as a
means of arresting the disease, making the patient bacteria-
rree, SO that by continued therapy there is a final re-establish-
ment restoring the patient to society.

The change here too is one of attitude. Lepers are being
treated without hospitalization, and in countries where the

problem is acute, but funds are scarce, the new methods are
bringing about a real change in outlook.

Prevention Versus Control

Speaking broadly the pubIic health movement is advancing
rapidly in the direction of control, prevention, and then
eradication.

This is reflected in the changed contents of medical school
curricula in the direction of preventive medicine.  It is
reflected in the greater emphasis of health benefits demanded
by labor, and broadly speaking in the entire social security
movement.

Health departments have been in the foreground of this
movement in modern medicine stressing prevention.  Better
a fence at the top of a precipice than a hospital at the foot,
is an old adage that still expresses the gist of the public
health attitude.

The entire shift in emphasis from control to eradication
when considered from this broad point of view is merely
one characteristic of a wider movement toward promoting
health and forestalling disease. This movement has been
making headway ever since the days when English statesmen
first promoted water supply and sewage disposal on the
simple thesis that a nation's health is a nation's wealth.
Viewed as a development of preventive medicine the new
emphasis on eradication falls neatly into place.

From a purely economic point of view prevention has al-
ways been attractive. Not only is an ounce of it worth a
pound of cure, but the great burden of the cost of sickness
obviously dwindles when it becomes possible to substitute
preventive for palliative measures.  Small and relatively
undeveloped countries do not have the capital for extensive
institutional care. If only a little money is available that
little money had better be spent right from the start on
preventive measures.

It is in line with some such general point of view that
we should consider the broad PASB policy of strengthening
health departments.

Strengthening Health Departments

Breaching the Line
The child population of Latin America is relatively large.
In part this is due to the high birth rate.  In Latin America
the group under 15 years of age constitutes 40.5 per cent of
the population. In other words nearly half of the population
are very young people.
Latin American countries have not only a young, but also

a fast-growing population. The population in South America
has doubled in 30 years.  The unusually rapid growth is
expected to increase at an even greater rate in the next 30
years. From 1920 to 1950 came a jump from 60,313,OOO to
110,510,OOO. By 1980 the population should double again
and be almost 223,000,OOO.
These facts concerning growth should be coupled with

17


Jeath rates. In eight countries of Latin America nearly one
half of the deaths, 49.1 per cent, occur in children under 5.
l,, other words every other funeral is a child under five. This
group under five constitutes only 15 per cent of the popula-
tion. That fifteen per cent of the population which has half
of the deaths is obviously the sector upon which those who
promote health should concentrate.

If the high death rates of certain parts of the Western
Hempishere are to be brought down, here is the point of at-
tack. Here is where the line can best be breached.

Other countries have breached it. The fact that 49.1 per
cent of deaths in Latin America are in the age group under 5
should be compared with a similar figure for Europe which
is 10 per cent. For Canada and the United States the figure
is 5.9 per cent. Australia and New Zealand get this figure
down to 7.3 per cent, This indicates that these early deaths
in Latin America are largely preventable.

In selecting the control of diseases in children as a major
point of attack the Fourteenth Pan American Sanitary Con-
ference, guided by its experts, followed the strategy of
seeking the weak point in the enemy's line.

If it is also remembered that the major cause of deaths
among children in some I8 South American countries were
the diarrheas, the recommendation to do something about
gistro-intestinal diseases in children begins to take on added
importance. Ready availability of large quantities of water
is helpful in preventing deaths from diarrheas and associated
rapid dehydration.

Deficiency of protein in the diet may be another factor.
Total protein, animal protein and milk protein, for children
in Canada and the United States is much higher than for
children in Latin America. The figures for the latter are 65,
25 and 9 grams per capita per day as opposed to the much
hi<;hc-r index for Canada and the United States of 90, 61 and
`23. In plain words North American children in general get
more proteins in the weaning age.

More information on these matters is given in the main
body of the Report.

Education and Training

iMuch has been made this year of the role of the PASB in
Pmviding technic.rl assistance in the way of scientific guid-
ance. Such imparting of up-to-date technical information
makes possible things that were impossible before.
i In addition to providing technical information the PASB
`p `ough fellowships and active support of seminars and
courses stresses education. More attention to the work of the
18 ureau in this field is given in ;I later section of this Report.
' A chief emphasis this year has been on strengthening both
SchooIs of medicine. and schools of public health.  A seminar
conceived on II broad international basis was organized and
successfully carried out to advance the subject of preventive
pedicine. At this seminar held in Chile, South American

countries established a pattern of cooperation in this field
which it is hoped will be repeated with 11 remaining countries
of Latin America at a similar seminar next year in Mexico.

There was inaugurated in 1955 a far-reaching survey of
pediatrics in the medical schools of Latin America. The
Bureau is continuing its efforts to distribute key printed mate-
rials, such as committee reports, studies, and bibliographies on
pedagogical procedures in the field of medical education. De-
tails on cooperative projects in aid of special medical schools
are given in the body of the Report. The same is true regard-
ing details of studies on nursing education and aid to courses
in nursing and for the training of nursing auxiliaries.

In general the aid to education recognizes the principle
that in all progress in the field of applied health provision of
well-trained personnel comes first.

The large foundations which were active in the first half
of the twentieth century, after blazing certain trails, are now
pulling out of the field of health application. They are
passing this type of work on to organizations such as the WHO
and the PASB. The PASB which has for 50 years been
striving for its present strategic position has the necessary
connections and must develop and maintain an adequate tech-
nical staff to fulfill its ever increasing obligations.

The reader is referred to the main body of the Report for
a detailed account of what the PASB is doing in the way of
support to fellowships and aid in the establishment of training
programs for personnel active in the direct application of
health me;lsures.


Pertinent Planning

If a single characterization were to be made of health con-
ditions in certain countries it would be that so far as water
supply, sewage disposal and other basic factors having to do
with environmental sanitation are concerned, these countries
are where the rest of the world, that is, the advanced coun-
tries, were 75 years ago. Hence in stressing as a major point
the need to improve environmental sanitation, the Fourteenth
Pan American Sanitary Conference was presenting an essen-
tial strategy.

The purpose of national health planning is to set up in each
country a series of activities to be developed in the next five
or ten years which will solve national health problems by
stages based upon the relative importance of the various
programs and upon the technical, economical, and cultural
position of the country.

Such planning breaks down into three major elements:
1) diagnosis of health problems, 2) clear view of remedies
needed for the solution, 3) application of these remedies on
a planned basis. The above is still too general for concrete use.
Planning proceeds more satisfactorily when it centers around
specific objectives. With this in mind guides and standards
for the implementation of programs are useful if they deal
with specific things such as laboratories, malaria, nutrition,
smallpox, waste disposal and integrated health services.
These integrated health services are, of course, also a
direct reflection of national health planning. With one eye

on the needs and another on the resources of a country, :L
health program is drawn up. This program may be active at
various levels, national, regional or local. The one single
practical consideration that makes these integrated programs
work is, to put it bluntly, good salaries. A basic desideratum
is to insist on full-time employment, adequate compensation,
stability of career, and, of course, technical competence.

Pan American Sanitary Bureau planning continues to center
around the three main topics of eradication, integration and
education. It is necessary to keep working at the eradication
of certain diseases. At the same time constant effort is needed
to strengthen the year-round work of health departments and
m the same way while these other two things are going on a
substantial amount, one-third perhaps, of the effort and money
should continue to be put into education.

To improve further on a planning program it is necessary
to deal specifically with the problems of different countries.
New information on these problems is being gathered every
year. At the next quadrennial Pan American Sanitary Confer-
ence to be held in 1958 there will be a general report on
health needs country by country. Meanwhile, through its con-
tacts, its field staff, its Zone Offices, its annual meetings and
its constant flow of personnel to and from the field, the PASB
is acquiring a working knowledge of conditions in each
country. It is on the basis of this knowledge that specific
projects are approved and implemented.

The work done in 1955 is discussed in detail in the Sections
of the Report which follow.

20