THE CONTRIBUTION OF EPIDEMIOLOGICAL STUDIES TO THE SOLUTION OF SOCIAL PROBLEMS

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332

THE

CONTRIBUTION

OF

EPIDEMIOLOGICAL

STUDIES

TO

THE

SOLUTION

OF

SOCIAL

PROBLEMS

Alexander D. Langmuir, M.D.

Epidemiology Branch, Communicable Disease Center, Public Health Service, Atlanta, Georgia

W

HEN I was first asked to prepare a

contribution to this Conference, I was

quite reluctant on the grounds that I was

neither a pediatrician nor a radiation epide-mioiogist. My chief relation to pediatrics is

that many of the epidemic diseases of

na-tional importance occur predominantly in

childhood. My only connection with

radia-tion epidemiology is my minor and

tran-sient participation ill what might be

re-ferred to as the epidemiological renaissance

of the Atomic Bomb Casualty Commission

during the mid 1950’s.

When I was asked to discuss how we at

the Communicable Disease Center had

ap-plied epidemiology to the solution of social problems in the nation, I could not refuse.

This meant to me that the term “social

problems” in the title included such

di-verse problems as the eradication of malaria,

the defense against biological warfare, the

rationing of gamma globulin and polio

vac-cines, the control of influenza, and the

trans-mission of botulism and salmonellosis in

canned and packaged foods in interstate

commerce.

We have summarized the role of federal

and state health agencies in the

contain-ment of such problems in “The Surveillance

of communicable Diseases of National

Importance.” I hope that some of the

expe-riences that I shall recount will have rele-vance to a broad discussion of the national significance of radioactive fallout.

Prior to World War II, the U.S. Public

Health Service assumed only limited

re-sponsibility in the control of communicable diseases in the United States. Many notable

research contributions were made by the

staff of the Hygienic Laboratory toward

controlling such diseases as Rocky

Moun-tain spotted fever, poliomyeiitis, peilagra, typhus, and influenza, but the day-by-day

job of controlling communicable diseases

was left to state and local health

depart-ments.

In the late 1930’s, the U. S. Public Health

Service assumed a new role of national

leadership, making a comprehensive effort

to control first syphilis then tuberculosis. At

the beginning of World \Var II, a major

program was undertaken to control malaria

around military bases and shipyards in the

Southeast. This program was the origin of

the Communicable Disease Center.

The first approach of the organization

known as Malaria Control in War Areas

(

MCWA

)

was traditional. Drainage,

larvi-ciding, and other established methods of

anopheline mosquito control were

success-fully applied. Although tens of thousands of

war veterans returned from the South

Pacific and North African theaters of activi-ty with peculiarly relapsing strains of vivax

malaria, there were no documented cases of malaria among new trainees.

At the end of World War II, DDT

revo-lutionized malaria control, and the U.S.

Public Health Service embarked on what

was then considered an ambitious, if not

foolhardy, program to eradicate malaria

from the country. It was known that the

southeastern part of the nation-from the

coastal plain of Virginia to the Gulf of

Mexico and the Mississippi Delta-was

tra-ditionally malarious. Thousands of cases

continued to be reported, and the return of

veterans threatened to seed malignant

strains in this area.

At this point, the MCWA was converted

into the Communicable Disease Center

and reorganized under a broad charter to

“aid the states in the control of communica-ble diseases,” but its first major assignment

was to eradicate malaria. It proceeded by

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333

spray the homes of all persons residing in

traditionally malarious areas. These were

thought to be well identified.

This program was embarked upon with

great enthusiasm. It was popular locally,

but it was not guided with close or sophisti-cated epidemiological scrutiny. In 1949 and

1950 with effective epidemiologicai

ap-praisal, two surprising discoveries were

made:

1. The voluminous reporting of malaria

cases-notably in Texas, Mississippi, and

South Carolina-was largely erroneous. The

diagnoses could not be confirmed.

2. The many positive laboratory reports

of malaria submitted from competent

pub-lie health laboratories were verified, but

these had unusual characteristics :

(

a

)

they came from all over the country, not just the

Southeast,

(

b

)

there were many more in

1946 and 1947 than subsequently, and

(

c)

they documented almost exclusively cases

in overseas veterans of World War II.

Thus, it became apparent that malaria

was no longer spreading as an indigenous

disease in this country; the confirmed cases that were occurring were the tail end of the

great malaria epidemic among our troops

overseas.’

Intensive surveillance of malaria was

then instituted. A careful search for

evi-dence of local spread failed to reveal any

episodes until the summer of 1952, when a

sharp outbreak occurred at a Camp Fire

Girls encampment in northern California, far from any traditionally malarious area. This

was traced to a Korean War veteran who

had camped out in the area shortly before

the girls arrived.

A mature review of the malaria story in

this country leads to the conclusion that

this disease, once the scourge of the South,

spontaneously disappeared between 1940

and 1945. The program of indoor residual

spraying-the origin of the Communicable

Disease Center-was initiated too late.

Ma-laria was gone, but we didn’t know it.

Epidemiology did not solve this “social”

problem, but it did serve to emphasize the

need for closer epidemiological guidance or

surveillance in the conduct of major nation-al control programs.

With the outbreak of war in Korea in

1950, the subject of defense against

biologi-cal warfare became an urgent national

problem.’ It was shrouded in secrecy and

confused by emotional controversy, but it

was a problem that responsible health

officials and epidemiologists could no

longer ignore.4 In all irreconcilable

contro-versy that continues to this day, one

over-riding concept received almost universal

support. This was the need for a greatly ex-panded supply of trained epidemiologists.

They could be essential in the event of a

biological warfare attack, and, in any event, they would be valuable for many peacetime services.

The Communicable Disease Center, with

its broad charter and its established

rela-tionships with the states, was the logical

U.S. Public Health Service agency to recruit

and train epidemiologists. To meet this

need, the Epidemic Intelligence Service

was formed. A quota of positions in the

medical draft was allotted, and in July 1951 the first class of 22 medical officers con-vened for an intensive course in practical field epidemiology and biostatistics prior to undertaking field assignments. In each

sub-sequent year a new group, varying from 10

to 47 officers per year, has been recruited

and trained. The program is continuing and

expanding. To date, a total of 377

profes-sional officers have been recuited : 282 phy-sicians, 49 veterinarians, 31 statisticians, and 15 representing other health specialties.

With this force of competent young

professional officers originally recruited for training, we have been able to staff a large

number of epidemiological programs and

provide a large volume of services to the

nation and to some extent to the world.

One major activity has been supplying

epidemic aid. Since 1951, we have never

failed to respond to a request from a state health officer for an epidemiologist or a team of epidemiologists to assist in the

investiga-tion and control of an outbreak. This

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an-swer 100 calls or invitations a year. This

service is comparable to an emergency

ward in a large city hospital-there is

al-ways excitement and there is vivid and

valid “clinical” material for training

pur-poses. In the Communicable Disease

Cen-ter we are constantly reminded of the

prob-lems that are cause for concern in the

states.

The availability of the large and steady

supply of professional competence has

per-mitted the development of the Program of

Surveillance of Communicable Diseases of

National Importance. Starting with malaria, each disease that has successively come into

national prominence has been brought

under surveillance. The major problems

in-elude poliomyelitis, influenza, viral hepati-tis, encephalitis, salmonellosis, shigeilosis,

rabies in animals and man, and now,

some-what belatedly, measles.

Before discussing certain specific

nation-al epidemic problems, mention should be

made of the subsequent careers of former

Epidemic Intelligence Service officers. A

total of 319 have completed their 2 years of

obligated duty. Only a few had a mature

interest in epidemiology or public health at

the time of their entry into our program; but, of the total, 80 (30%) have remained in the U.S. Public Health Service as career officers. Another third have accepted

full-time, academic positions in research and

teaching with heavy epidemiologicai

em-phasis; 5% are now in full-time

employ-ment in state and local health departments.

Almost all Epidemic Intelligence Service

trainees have elected to remain in the

com-missioned reserve of the U.S. Public

Health Service and thus are on call in any

national emergency. In a broad sense,

therefore, the Epidemic Intelligence

Ser-vice has contributed to the solution of a so-cial problem.

From its inception, the Communicable

Disease Center has been involved in

prob-lems of poliomyeiitis. In spite of many

co-gent arguments that this disease was a rela-tively minor public health problem,

nation-al attention was focused on it, and thus it

became a major “social” problem that

epi-demiologists in official positions could not ignore or derogate.

The Center’s first effort to control polio

epidemics aborted because it was based on

the faulty hypothesis that the disease was

fly borne. In 1952, William Hammon, M.D.,

of the University of Pittsburgh,

demon-strated the effectiveness of gamma globulin in epidemics of poliomyelitis. This

discov-ery had serious implications for public

health. The total supply of gamma globulin was limited and strictly rationed for miii-tary purposes. Whether this prophylactic

could be used effectively in public health

practice was questioned by many health

officers and epidemiologists. In 1953, the

full resources of the Center were directed to a practical evaluation of this procedure.

Unfortunately, the outcome was discourag-ing to the enthusiasts. It was rather

persua-sively shown that gamma globulin had little practical usefulness in the control of polio-myelitis.

With the development of the inactivated

poliomyelitis vaccine, a more optimistic

story unfolded. In 1954, 15 Epidemic Intel-iigence Service officers were assigned to

as-sist in the famous Francis Field Trial. As a

result, in 1955 with the grand

announce-ment of its success, the Center had a large cadre of epidemiologists specially trained

to assist in solving the acute problems of

rationing the short supply, in evaluating the

complex issues of the Cutter incident, and

in overcoming subsequent problems of low

potency of the vaccine.

A brief summary of the Cutter incident

will illustrate the role of epidemiology in

helping solve a national emergency. In late April, when the limited supplies of vaccine

were being given largely to first and

sec-ond grade schoolchildren, six cases of polio

were reported among children who had

re-ceived vaccine from either of two lots

manu-factured by Cutter Laboratories. These

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Health Service asked the Cutter

Laborato-ries to recall their vaccine and issued a

public statement to that effect. He also

di-rected the Communicable Disease Center

to establish an emergency national surveil-lance of poliomyelitis.

The whole polio vaccine program was

se-riously threatened. In the ensuing confusion

of claims and counterclaims and honest

confusion as to the significance of the

evi-dence, the polio surveillance program

pro-ceeded to collect detailed data on each case of polio as it occurred in the country and to disseminate the factual finding to state and national health officials, all research

scien-tists concerned with the problem, and all

manufacturers of polio vaccine.

As a result of the steady flow of increas-ingly precise surveillance data, it soon

be-came apparent that the problem was

confined to two production lots of Cutter

vaccine and not to the basic manufacturing

process of the vaccine. The major vaccine

producers remained in production, albeit

with more rigid controls. The vaccine

pro-gram was restrained, but did not collapse. For the first 6 weeks of the Cutter incident,

the epidemiological data provided the only

scientific basis for understanding what was going on.

Subsequently, the surveillance program

established in the emergency of the Cutter

incident provided the background data for

various problems and pitfalls, both the an-ticipated ones and the complete surprises,

that were encountered in the great

con-quest of poliomyelitis. These included: (1) the low potency of vaccine, particularly the

Type III component, resulting from the

extra filtration step instituted in produc-tion; (2) the concentrated epidemics of un-precedented severity in the slums of Chica-go, Detroit, Kansas City, Des Moines,

Prov-idence, and elsewhere; (3) the problems of

the SV 40 virus and its oncogenicity in both live attenuated and formalin inactivated vaccine; and (4) the knotty issues of resid-ual virulence of the oral vaccines,

particu-larly following the administration of Type

III to adult males.

In the spring of 1957, when Asian

influenza broke out of China through Hong

Kong and spread to the Philippines,

Tai-wan, and Singapore, epidemiologists

throughout the world predicted a

world-wide pandemic which would spread first to

the tropics and southern hemisphere

be-cause winter was then beginning but

threatened to spread to the northern

hemi-sphere and the western world by late

sum-mer and early fall. While the early epidem-ics in Asia were of only moderate severity, the specter of the 1918 influenza pandemic

was only too apparent, and the fear of a

malignant second wave phenomenon was

seriously entertained by some distinguished

students.

The U.S. Public Health Service

under-took to lead a comprehensive national

pro-gram to prepare for the pandemic and

con-tam it if possible. One of its ambitious steps was to sponsor production of large volumes

of monovalent influenza viral vaccine for

mass immunizations. Another feature of this

program was a truly global surveillance of

influenza. A network of reporting centers, based not only on state and local health

de-partments but also on more than 100 labo-ratories qualified to diagnose viral influenza,

was established. A regular surveillance

re-port summarizing current specific

mnforma-tion in detail was issued twice a week

throughout the summer. This served as an

authoritative source of up-to-the-minute

in-formation, not only on the occurrence of

clinical illness, outbreaks, and epidemics but also on the availability and use of vac-cine and the treatment of cases and compli-cations.

The epidemic came as predicted. The

vaccine production was a few weeks too

late, so the epidemic could not be

con-tained. Its severity was fortunately only

moderate. The country was prepared and

met the emergency with a minimum of

dis-ruption and essentially no public hysteria.

The surveillance program served as an

es-sential feature of the whole control

pro-gram.

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might be recounted if time permitted, but I shall mention only a few:

(

1

)

the detection of raw shellfish as the vehicle of infection of

infecfious hepatitis; (2) the incrimination and bringing to trial for alleged criminal

negligence of a physician who had in his

practice 40 cases of serum hepatitis with 15

deaths

(

the prosecutor’s case was based

wholly on the epidemiological evidence);

(

3) the detection of contaminated food

products in interstate commerce, such as

canned tuna fish that caused botulism or a

dietary food supplement that spread

salmo-nella infection.

Four general principles of surveillance

have been developed and tested over the past two decades :

(

1

)

reporting, (2

)

inves-tigation, (3

)

evaluation, and (4

)

dissemina-tion of facts.

The reporting system must be

compre-hensive and responsive. It should include

not only the registration of deaths and the

collection and tabulation of reports of cases of the notifiable diseases but also reports of

significant isolations and identification of

pathogens in laboratories. In addition,

other pertinent data are most useful; these include surveys of minor illness, of immuni-zation status, of skin test sensitivity to tu-berculin or histoplasmin, and of serological, bacteriological, or x-ray findings in well,

se-iected population groups. There must be

some central clearing house for all of these

systematic and special reports where the

data are tabulated and consolidated for

study and review.

When reports reveal findings of possible

significance, there must be a mechanism for

immediately and thoroughly investigating

every rumor and lead. Telephone inquiry is

the simplest method. When evidence points

to a significant outbreak, a mobile team of

epidemiologists supported by adequate

lab-oratory services is essential. Here is where

the Epidemic Intelligence Service has

proved itself to be so valuable. Each

inves-tigation must be specially designed to fit

the immediate circumstances and must be

of such scope and character as adequately

to verify or exclude the original report.

The third principle flows directly from

the second; namely, the findings must be

carefully evaluated. There must be a staff

qualified by training and experience to

evaluate the findings and determine their

scope and significance.

Finally, all their effort is meaningless

an-less the facts and their evaluation are

brought to the attention of all those who

hold responsibility in the situation or who

for other reasons have a need to know. For

acute communicable diseases, health

of-ficers at all levels and their advisers hold

this responsibility. In most situations the

general public should be given information as soon as the facts can be reasonably

inter-preted.

A word about the calibration of the

sys-tem. Epidemiological data are notoriously crude. Reported cases of notifiable diseases, the figures derived from the decennial cen-sus, and tabulations based on field surveys are the stock-in-trade of the epidemiologist.

These can hardly compare with the more

quantitative determinations of the micro-biologist, the chemist, and the radiation physicist. At times, however, epidemioiog-ical survey analysis can be exquisitely sen-sitive.

Failure to recognize what was going on

with malaria in this country during the

middle and late 1940’s was not a failure of

the epidemiological method so much as a

failure to apply sound methods. It was as

naive as the failure to install an adequate

fire alarm system in the Windscale Atomic

Reactor.

By the mid 1950’s the reporting of

polio-myelitis had developed to a high degree of

accuracy and completeness. For example,

the Cutter incident in 1955 was detected

and corrective action taken on the basis of

six cases. The trouble with Sabin vaccine

from 1962 to 1964 was detected and

inten-sive planning of control measures was

ini-tiated on the basis of 11 cases. It took 2

years to achieve a resolution because the

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credibility. The final data comprised a total of 57 cases associated with approximately 300 million doses of vaccine administered.5 Tile highest rate, that associated with Type III vaccine given to young adult males, was only 0.64 X 10-s, which I am told is similar

in order of magnitude to the threshold of

measurement of many biological effects of

radiation.

With certain rare types of salmonella in-fection, it is possible to detect contamina-tion of a food product sold in interstate

commerce with only a handful of reports.

Likewise, a few years ago the occurrence of

only three cases of botulism following ingestion of canned tuna fish led to a

com-plete overhaul of a large cannery and the

destruction of several hundred thousand cans.

At the Communicable Disease Center we

have a simple rule of thumb in such

mat-ters. The occurrence of a single case of an untoward event is a matter of real interest

and warrants full investigation. Two cases

within a short period of time, even if

widely separated geographically, give cause

for deep concern. Three cases constitute an

“incident” with all the national implications that follow.

How does epidemiology relate to

ra-dioactive fallout? To practice epidemiology

there are only two required

essentials-cases and a population. The population is

evident, namely, the whole world. The

cases are more evanescent and vague. This

raises an interesting analogy with a situa-tion existing until recently with viral dis-eases.

With the development of tissue culture

techniques in the early 1950’s, virologists

began isolating a wide variety of new

vi-ruses. One group was, for a time, generally

designated the “ECHO viruses,” standing

for Enteric Cytopathic Human Orphans.

These viruses were known as “orphans in

search of a disease.” In recent years most of them have been identified with the illnesses they cause and have lost their orphan state.

It seems evident that, at this state of

de-velopment of the epidemiology of

radioac-tive fallout, there are many orphan isotopes

searching for their diseases. I have no

doubt these will be identified by observant

clinicians and epidemiologists. Already

there are the established relationships of

radiation to leukemia, to skin cancer, to

thyroid adenomas and now thyroiditis, to

bone cancer in radium dial painters, and to

epithelioma of the mastoid sinuses. On the

valid ground of looking for specific effects,

one might wonder if the localization of

ra-diocesium in muscle will lead to

rhabdo-myosarcoma in Eskimos. It has always

seemed likely to me that the survivors of

atomic radiation in Hiroshima and

Naga-saki would develop cancer of the gastroin-testinal tract, since whole body radiation denudes the intestinal epithelium. Experi-ence to date has not supported this

specula-tion.

A more systematic, precise, and

sophisti-cated surveillance of congenital defects on

a national, if not international, scale would

seem to be prudent if the occurrence of

clusters could be related to established

pat-terns of radiation in the environment. The

metilods that have proved useful in the

sur-veillance of communicable diseases of

na-tional importance should be readily

adapt-able to problems of the surveillance of

ra-dioactive fallout and its associated diseases.

REFERENCES

1. Langmuir, A. D. : The surveillance of

corn-municable diseases of national importance. New Eng. J. Med., 268:182, 1963.

2. Andrews, J. M., Quinby, G. E., and Langmuir,

A. D. : Malaria eradication in the United

States. Amer. J. Public Health, 40: 1405, 1950.

3. Langmuir, A. D.: The potentialities of biological

warfare against man: An epidemiological

ap-praisal. Public Health Rep., 66:387, 1951.

4. Langmuir, A. D., and Andrews, J.M.: Biological

warfare defense: 2. The Epidemic Intelligence

Service of the Communicable Disease Center.

Amer. J.Public Health, 42:(3), 1952.

5. Henderson, D. A., Witte, J. J.,Morris, L., and

Langmuir, A. D.: Paralytic disease associated

with oral polio vaccines. J.A.M.A., 190:41,

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1968;41;332

Pediatrics

Alexander D. Langmuir

OF SOCIAL PROBLEMS