1. J., and Warren, K. (1979). "Selective PHC -an interim
strategy for disease control in developing countries." The New
England Journal of Medicine 30(18): 967 -974
Walsh,

2. Vol. 301 No 18 DISEASE CONTROL IN DEVELOPING COUNTRIES -WALSH A:--'D WARREN
SPECIAL ARTICLE
SELECTIVE PRIMARY HEALTH CARE
An Interim Strategy for Disease Control in Developing Countries
JULIA A. WALSH, M.D., AND KENNETH S. WARREN, Yt.D.
Abstract Priorities among the infectious diseases af- tussis-tetanus vaccination, treatment for febrile
fecting the three billion people in the less developed malaria and oral rehydration for diarrhea in chil-
world have been based on prevalence. morbidity. mor- dren, and tetanus toxoid and encouragement of
tality and feasibility of control. With these priorities in breast feeding in mothers. Other interventions might
mind a program of selective primary health care be added on the basis of regional needs and new de-
is compared with other approaches and suggest- velopments. For major diseases for which con-
ed as the most cost-effective form of medical inter- trol mea?ures are inadequate. research is an inex-
vention in the least developed countries. A flexi- pensive approach on the basis of cost per infect-
ble program delivered by either fixed or mobile ed person per year. (N Engl J Med 301:967-974,
units might include measles and diphtheria-per- 1979)
T HE three billion people of the less developed Absolute poverty is a condition of life so characterized by
world suffer from a plethora of infectious dis- malnutrition, illiteracy. disease, high infant mortality and low life
exp~ctancy as to b~ beneath any reasonable definition of human
.,eases. Because these infections tend to nourish at the
decency'
poverty. level, they are important indicators of a vast
~ate of collectiv,= ill health. The concomitant dis- How then, in an age of diminishing resources, can
'ability has an adverse effect on agricultural and in- the health and well-being of those "trapped at the bot-
dustrial development, and the infant and child mor- tom of the scale" be improved before the year 2OOO? A
tality inhibits attempts to control population growth. valid approach to this overwhelming problem can be
What can be done to help alleviate a nearly un- based on the realization that the state of collective ill
broken cycle of exposure, disability and death? The health in many of the less developed countries is not a
~t solution, of cQurse, is comprehensive primary single problem. Traditional indicators, such as infant
health care, defined at the World Health Organiza- mortality or life expectancy, do not permit a grasp of
tion conference held at Alma Ata in 1978 as the issues involved, since they are actually composites
of many different health problems and disorders.
the attainment by all peoples of the world by the year 2000 of a
Each of the many diseases endemic to the less
~l of health that will pcnnit them to lead a socially and
.economically productive life. Primary health ~ includes at developed countries (Table 1) has its own unique
lcast: education concerning prevailing health problems and the cause and its own complex societal and scientific
methods of preventing and controlling them; promotion of food facets; there may be several points in the process for
supply and proper nutrition, an adequate supply of safe water which interventions could be considered.'-s
&nd basic sanitation; maternal and child health ca~, including
family planning; immunization against the major infectious dis-
Thus, a rationally conceived, best-data-based,
c cases; prevention and control of 1~lIy endemic diseases; ap- selective attack on the most severe public-health
, propriate t~tmcnt of common diseases and injuries; and provi- problems facing a region might maximize improve-
sion of essential drugs.' ment of health and medical care in less developed
The goal set at Alma Ata is above reproach, yet its countries. In the discussion that follows, we try to
very scope makes it unattainable because of the cost show the rationale and need for instituting selective
and numbers of trained personnel required. Indeed, primary health care directed at preventing or treating
the World Bank has estimated that it would cost bil- the few diseases that are responsible for the greatest
lions of dollars to provide minimal, basic (not com- mortality and morbidity in less developed areas and
prthtnsive) health services by the year 2000 to all the for which interventions of proved efficacy exist.
poor in developing countries. Tht bank 's pr~sident,
ESTABLISilINC PRIORITIES FOR HEALTH CARE
Robert McNamara, offered this somber prognosis in
~ annual report in 1978: Faced with the vast number of health problems of
mankind, one immediately becomes aware that all of
Even if the projected -and optimistic -growth rates in the them cannot be attacked simultaneously. In many
developing world arc achieved, some 600 million individuals at
the end of the century will remain trapped in absolute poverty
regions priorities for instituting control measures
must be assigned, and measures that use the limited
0
~ human and financial resources available most effec-
~ From Ibe Rockefeller Foundation, 1133 Avenue of Ihe Americas, New
tively and efficiently must be chosen. Health planning
'!rOfk. NY 10036, whcre reprint requests may bc addressed 10 Dr Warren. for the developing world thus requires two essential
~ Pracnlcd al a meeting on Heallh and Population in Dcveloping steps: selection of diseases for control and evaluation
lrics, cosponsored by Ihe Ford Foundalion,lhe International Dcvelop-
~.1 Research Center and the Rockefeller Foundation and held at Ihe Bel-
of different levels of medical intervention from the
~ Study and Confcrencc Center. lake Como. Iiaiv. April. 1979 most comprehensive to the most selective.

3. 968 THE NEW ENGLAND JOURNAL OF MEDICINE Noy I, 197~~
.
Selecting Diseases for Control long-~erm improvem~nts i~ sanitary and agricultural
practices to reduce reinfection. In View of the difficulty
In selecting the health problems that should receive of eliminating exposure to the roundworm and the low
the highest priorities for prevention and treatment, morbidity associated with the infection, ascariasis
four factors should be assessed for each disease: deserves less attention than its ubiquity seems to sug-
prevalence, morbidity, mortality and feasibility of gest.
control (including efficacy and cost). Malaria is associated with a far smaller mortality
Table 2 illcorporates these factors into an analysis rate than that of Lassa fever and a far lower
of three representative illnesses of the less developed prevalence that that of ascariasis. Yet its mode of
world. The newly discovered Lassa fever was as- transmission is well known, and it produces much
sociated with a 30 to 66 per cent mortality rate in the recurring illness and death; about one milliQn
few limited outbreaks recorded in Nigeria, Liberia children in Africa alone die annually from malaria.'
and Sierra Leone. Those who survived recovered fully What also distinguishes malaria from Lassa fever and
after an illness lasting seven to 21 days. Although this ascariasis is that it can be controlled through regular
fatality rate seems to suggest giving Lassa fever high mosquito-spraying programs or chemoprophylaxis.'.'
priority in a major health program, the prevalence of Of these three infections, then, malaria would be as-
overt disease appears to be low. Furthermore, the only signed the highest priority for prevention in the mOSt
treatment available is injections of serum from effective approach to reducing morbidity and mor-
patients who have recovered. Since its mode of trans- tality.
mission is unknown and there is no vaccine, Lassa By means of the process outlined above for Lassa
fever is impossible to control at present.' Therefore, fever, ascariasis and malaria, the major infections
concentration on preventing Lassa fever would be endemic to the developing world (Table 1) wC!"t
neither efficient nor efficacious. evaluated and assigned high (I), medium (II) or low
Ascaris, the giant intestinal roundworm, causes the (III) priorities. Within categories exact rank is not d
most prevalent infection of man, with one billion cases major importance, and rank may change or items may
throughout the world.7 Yet disability appears to be be added or deleted, depending on the geographic
minor and death relatively rare.)" Treatment. howev- area under consideration. For instance, schistosomia-
er, requires periodic chemotherapy for an indefinite sis, to which a high priority was assigned, does not
period.).'" Control may ultimately require massive, occur in many areas of the developing world. Our ~
Table 1. Prevalence. Mortality and Morbidity of the Major Infectious Diseases of Africa. Asia and Latin America. 1977-1978..
IN'ECTION l"nc-no1'S D.."'. (THO~"'OS
0 Of AVE""'E ~O. Of
D.n Of LJfElosT
RounO£
(THO"..,,"osfYa) (THOVS"'OS/V,) PtaSOMAl.
c..ES/Ya) (PE. ~E) Dt...aIUTTf
Diarrheas !-5,OOO,000 5-10,000 3-5,CXXJ,CXXJ 3-S 2
Respiratory inrcctions 4-SOOO 5-7 2-3
Malaria 800,000 1200 1SO,CXXJ 3-S 2
Measles 85,000 900 80,CXXJ I~I~ 2
Schist~omiasis 200,000 500-1 000 20,CXXJ 6(»-1 (XX) 3-4
Whooping cough 70,000 2s0..450 2O,CXXJ 21-28 2
Tuberculosis 1,000.000 400 7CXXJ 200-400 3
NeonatalteLanus 120-180 100-150 120-180 7-10 I
Diphtheria 40,000 ~ 700-900 7-10 3
Hookworm 7-900,000 S(}-6() 1500 100 4
South American trypan- 12,000 60 1200 600 2
osomiasis
Onchocerciasis
Skin disease Low ':CJ.~:-
2 -)XX) 3M
---3
3O,CXXJ
River blindness 20-50 200-500 J<XX! 1-2
Meningitis I SO 30 ISO 7-10 1
Amebiasis 400,CXXJ 30 1500 7-10 3
Ascariasis 800,OOO-I,CXXJ,OOO 20 I<XX> 7-10 3
Poliomyelitis 80,000 10-20 2<XX> J<XX!+ 2
Typhoid 1000 25 500 14-28 2
leishmaniasis 12,000 5 12.
<XX> I100-200 3
Arrican trypanosomiasis 1000 10 ISO I
leprosy Very low 12.<XX> 5OQ-J<XX! 2-:
Trichuriasis 500,000 Low 100 7-10 ,
Filariasis 2SO,OOO Low 2- )<XX) 1000 3
Giardiasis 200,000 Very low 500 5-7 J
Dengue 3~ 0.1 1-2<XX> 5-7 2
Malnutrition 5-800,000 2(XXJ
-
°S.oed on c",mol« from .he World Hc.ilh Orl.no.."on .nd it, Spc.-,.1 PrOlr...mc lor Rcscorch.nd fr.,n,nl onfropoc.. 0, confirmedor modifIedbyc.,r.pot..
from publ.'hcd cp,dcm,olo"c ..ud... perlormcd ;n well dcr.ncd popul."on, (!CO,clc,cnc«) f'IU'« du nol .1.." m..ch ,h.". ofT.:i.lly rC'Ortcd.
b..: ."'"rrcpo"'"
,rc..
'I dcno,c, bcdr,ddcn. 2 .blc 10 I.nc"on on own '° "'.., c"C.' ..,mo.t.,or) " ..m,no,

4. Vol 301 No 18 DISEASE CONTROL IN DEVELOPING COUNTRIES -WALSH AND WARREN
969
Table 2. An Approach to the Establishment of Priorities for Disease Control, Based on Prevalence, Mortality, Morbidity and
Feasibility of Control of Three Representative Infections.
cno.. Po.,V4UNCO MOOT.un Mo'.,Oln FE.SI8tUTV ~IOOITY
Of CONTaOL
La... rever Unknown High (3(}..66%) Moderate Extremely poor Low: prcvllCDce
(lhoughllo (bedridden at present low, fcasibility
below) 7-21 days) of coDlrol poor
Exlrcmcly high Extrcmcly low Low (minor dIs- Poor(conlinuous Low: morulily
(lhoughllo .ffect (approximately ability &. drug lrcalmen! &I.morbidilY
I billion pcoplc) 0.001%) orten asymp- required) low, fcasibilily
tomatic) of CODlrolpoor
Malaria High (morc than Low (approxi- High (severe, Good (chcmoprophy- High: prcvalcnce
300 million in- matelyO.I%) many compli- laxis avaibble; high, morbidity
fcctcd annually) ~Iions, orten regular spraying high. fcasibilily
recurrcnt) programs(or of CODlrolload
vectorspratticol)
suits and rationale for the proposed hierarchy are list- A medium or low priority was assigned if control
ed in Table 3. measures were inadequate. For example, there is no
Group I contains the infections causing the greatest acceptable therapy for chronic Chagas' disease.}"
'amount of most readily preventable illness and death: Only toxic drugs and procedures of unknown efficacy,
~diarrhealdiseases,malaria, measles,whooping cough, such as nodulectomy, are available for treatment of
!schistosomiasis and neonatal tetanus. With the excep- onchocerciasis.}" Leprosy and tuberculosis require
tion of schistosomiasis, all the infections receiving years of drug therapy and even longer follow-up
~~hest priority for health-care planning affect young
:hildren more than adults. 10-14 Together with respira-
tory infections and malnutrition, they account for Table 3. Priorities for Disease Control in the Developing
of the morbidity and mortality among infants World. Based on Prevalence. Mortality. Morbidity and Feasi-
and young children.II.ls-11Members of this age group bility of Control.
(five years old or less) have a death rate many times PR'ORrn REASONS
ro. ASS'GN"E'" TO THIS CARGO.T
greater than that of their counterparts in Western GROUP
countries -accounting for 40 to 60 per cent of all I High High prcvalence, high mortalily or high
mortality in most less dc:velopedcountries.II,J1-1' in-
If morbidilY, clTcx:tivccontrol
DiarThcal diseascs
fant and child deaths from these infections are Mcaslcs
reduced, a large declinc: in the overall death rate will Malaria
:result. Such a situation would bc:an optimal outcome Whooping cough
Schistosomiasis
-a selective disease-control program. NconalaltCUnus
Groups II and III contain health problems that are
~itherless important or more difficult to control. Res- I( Medium
Respir2tory infections H~h prevalence, high monalilY, no
Jlratory infections, a major cause of disability and e/f..:tive control
~th, are not listed in Group I because of the dif- Poliomyelitis Higb prevakn<X, low monality,
e/f..:tive control
[Iculties involved in preventing and managing them. A Tuberculosis High preva1coce, high mortality,
Mae variety of viruses and bacteria are associated <:antra!difrocult
r with pulmonary infections, and no specific causative Onchocerciasis Medium prnalen<x, high morbidity, low
mortalitY, control difrlCUll
igent has been found in most patients.I,,20As in the Meningitis Medium prnaJen<x, higb mortality,
lI1dustrialized world, where pneumonia is frequently control difficull
ne tenninal episode in elderly patients weakened by Typhoid Medium prnalen<x, high monality,
r ;ancer or cardiova~lar
:Tact
disease, lower-respiratory-
infections affect children in developing countries
Hookwonn
conlrol difficult
High prnalen<x,low mortality,
conlrol difficult
Malnutrition
Whoare already afflicted with chronic malnutrition High prevalen<x, high morbidity,
control complex
Ind parasitic infections. I' Pneumococcal and in-
luenza vaccines prevent only a small percentage of III low
South American trypanoso- Control difficult
:ases,and influenza immunization must be given miasis (Chagas' disease)
lmost yearly because the virus changes antigenical- Arrican trypanosomiasis low prevalcncc. control difficult
y. When penicillin injections were given to all leprosy Contro! difficult
Ascariasis low mortality, low morbidity,
hildren with clinical signs of pneumonia in the rontrol difficult
~,arangwal Project in India, the mortality rate Diphtheria Low mortality, low morbidity
Amebiasis Control difficult
~~reased by SO per cent,21 but this method must be leishmaniasis Control difficult
~aJuate? ~ore extensivel.ybefore it. can be re~arded Giardiasis Control difficult
!~~ ffiaJor Improvement In prevention of respiratory Filariasis Control difficult
Dengue Control difficult
~sc:.

5. 970 THE NEW ENGLAND JOURNAL OF MEDICINE Nov. 1979
pcriods to cnsure cure.4.22.23In~tcad of attempting im- poor in developing countries by the year 2000 will b6
mcdiate, large-scale trcatment programs for these in- $5.4to $9.3 billion (in 1975 prices).26This investmentj
fections, the most efficient approach may be to invest which includes only initial capital investment and
in rcsearch and developmcnt of lcss costly and morc training costs, would provide one community healt
efficacious means of prevention and thcrapy. To worker or aux.iliary nurse-midwife for every 1500 t~
reiterate, the most important factor in e~tablishing 2000 people and one health facility for every 8000 t
priorities for endemic infections, even when evaluating 12,000people or every 10 km2, whichever is g~ater. In!
discaseswith high case rates, is a knowlcdge of which the model area in Africa, the World Bank estimateul
diseases contribute most to the burden of illness in an that supplying the minimum ca~ offe~d by buildi~
area and which arc rcasonably controllablc. one health post with one vehicle per 10,000people and
train.ing 125 auxiliary nurse-midwives and 250 coml
mumty health workers would cost $2,500,000, or $S
EVALUATING AND SELEcTING MEDICAL INTERVENTIONS
per capita. To this figure must be added the recurren~
Once diseases al'e selected for prevention and treat- costs of salaries, drugs, supplies and maintenance;
ment, the next step is to devise intervention programs Other costs not included are for training facilities;
of reasonable cost and practicability. The interven- continuing education, expansion of referral services
tions relevant to the world's developing areas that are and development of communication, transportation
considered below are comprehensive primary health and administrative networks to supply and manage
care (which includes general development as well as the health facilities. Furthermo~, the effectivenessof
all systems of disease control), basic primary health this model program for averting deaths or applying
care, multiple disease-control measures (e.g., insec- such preventive measures as education in sanitation
ticides, water supplies), selective primary health care, and nutrition has not been clearly established.
and research. Below is a discussion of each approach, The pilot projects for providing basic health-care
with emphasis on the relative cost involved in undel'- services that have been evaluated vary in their effec-,
taking and maintaining these programs and on the tiveness in improving the general level of health care.!
bendits that have accrued. For example, an outside evaluation of primary health!
This section of our analysis relies on reported service in Ghana revealed that a third to half the pop.4
results from individual studies conducted in various ulation of the districts lived outside the effective reach!
parts of the world. In addition, we have examined es- of health units providing primary care. Only abou~
timates of cost and effectiveness in terms of expected one fifth of the births were supervised by traine~
~
of five years had been seenin a child.,health clinic, an ..,
deaths averted by each intervention for a model area midwives; only one fifth of the children under the a
in Africa. The model area is an agricultural, rural por-
tion of Sub-Saharan tropical Africa with a population two thirds of the population lacked environment
of about 500,000 (100,000 are five years old or less). sanitation services. Furthermore, the services we
For reference purposes, the average figures for Sub- often of poor quality, notably in the crucial area oB
Saharan Africa will be used: the birth rate is 46 per child care.21.2. i
thousand total population, the crude de3th rate 19 per The cost and effectiveness of several experiment
thousand total population, and the infant mortality programs providing primary health care in localize ~
rate 147 per thousand live births.24.%S areas have been compared in Imesi, Nigeria2'
Comprehensive versus Basic Primary Health Care Etimesgut, Turkey]O,)I; Narangwal, India21;jamkhedJ
Indian.)); Guatemalan villages"; Hanover, jamai~
Comprehensive primary health care for everyone is ca)5-)1;and Kavar, Iran.» The estimated cost ped
the best available means of conquering global dis- capita varied widely among the programs, partiCUl
ease, the humane and noble goal declared at Alma ly because they were initiated at different times ove~
Ata. As defined by the World Health Organization, the past 15 to 20 years and furnished different servic
this system encompasses development of all segments to their communities. In general, however, the cos
of the economy, ready and universal access to curative per capita ranged between 1 and 2 per cent of thCJ
care, prevention of endemic disease, proper sanitation national per capita income of the particular countrvJ
and safe water supplies, immunization, nutrition, The cost for infant deaths averted were difficult r
health education, maternal and child care and family compare because of the paucity of control groups an"
planning. Since resources available for health pro- inconsistency of the population groups monitored~
grams are usually limited, the provision of compre- Figures ranged from $144 to $20,000, with a media
~ 1
hensive primary health care to everyone in the near fu- of 1700. The only precise calculations for the costs pe
ture remains unlikely. infant death averted ($ 144) or child death averte
Basic'primary health-care systems are far more cir- (1988 per one to three-year-old child) were for
cumscribed in their goals, which are to provide health medical-care and nutrition-supplementation projec~
workers and establish clinics for treating all illnesses in Narangwal, India.21 The estimates were muc
within a population. Nevertheless, this approach is far higher for deaths averted by nutrition supplements. ~
from inexpensive. The World Bank has estimated that Under some circumstances, programs of basi
tht: cost of furnishing basic health services to all the primary health care have been successful,but the cos

6. Vol 301 No. 18 DISEASE CONTROL IN DEVELOPING COUNTRIES -WALSH AND WARREN
and the degree of improvement in community health about $3.70 and good r~sults hav~ b~en r~port~d: th~
have varied markedly enough that refinements in the preval~nc~ of th~ inf~ction has d~cr~as~d from 45 to 35
approach are still needed. p~r c~nt in adults and from 21 to 4 p~r c~nt in
childr~n. D~spit~ th~s~ h~art~ning figur~s, ~radication
Multiple Dlsease-Control Measures of th~ v~ctor cannot b~ consid~r~d on th~ horizon.
These interventions, which include vector control, Schistosomiasis is a long-t~rm, chronic inf~ction and
water and sanitation programs and nutrition sup- th~ d~ath rate will not b~gin to d~clin~ until many
plementation, are more specific and easily managed y~ars aft~r continuous mollusk control.
than primary health-care programs, and they control
many similarly transmitted diseasessimultaneously. Water and Sanitation Programs
They can decrease mortality and morbidity and have Proper sanitation and clean water make a substan-
served as interim strategies for health care in less tial difference in the amount of disease in an area, but
developed countries. the financial investment involved is enormous. The
success of such projects also depends on rigorous
VectorControl maintenance and alteration of engrained cultural
Vcctor control is directcd at managing thc insects habits.
and mollusks that carry human disease. 111is ap- With the installation of community water supplies
proach has thc advantagc of bcing comparativcly in- and sanitation in developing areas, deaths from
cxpcnsive, but it must be continucd indcfinitcly and typhoid can be expected to decrease 60 to 80 per
may be cphemcral sincc thc vcctors tcnd to bccome cent,') deaths from cholera 0 to 70 per cent,')'" from
rcsistant. Thc cxamplcs bclow rcvcal somc of thc com- other diarrheas 0 to 5 per cent,"-SI from ascaris and
plcxities of maintaining vector control. other intestinal helminths 0 to 50 per cent'.10.S2-S.
and
Thc control of malaria transmission through inscc- from schistosomiasis 50 per cent'2.S2 (after 15 to 20
,ticides has becn highly cffectivc. In thc tropical years). The World Bank has estimated that the cost of
'regions and savannas of Africa, twicc-ycarly spraying providing community water supplies and sanitation to
~ dccrcased thc crude dcath ratc by approximatcly all those in need by the year 2000 will be $135 to $260
~ pcr ccnt and infant mortality by 50 pcr ccnt.)"" billion.26.ss Construction of a rural community stand-
"I11cWorld Hcalth Organization has cstimatcd that pipe costs 120 to 126 per capita, and rural sanitation
thc avcrage cost for housc-to-house spraying with costs $4 to $5 per capita. In urban areas the costs are
chlorophenothanc (DDT) is $2 pcr capita annual- $31 and $23, respectively. In our model area of Sub-
ly.' Thcrcforc, thc cost pcr adult and infant dcath Saharan Africa the initial investment would be $12 to
avcrtcd is $250, and the cost pcr infant dcath S15 million. If amortization and annual maintenance
avcrtcd is $600. Unfortunatcly, cradication of malaria costs are only 10 per cent of this sum, the annual cost
with insccticides is bccoming morc difficult to ac- per deaths averted will be $2400 to $2900, and the cost
complish. Bccausc mosquitocs can bc cxpcctcd to per infant and child deaths averted will be $3600 to
bccomc rcsistant to DDT within a few years, othcr, 14300.
:muchmore expcnsivc pcsticidcs must bc substituted; What must be realized is that the above sums are
ithc usc of propoxur or fcnctrithion will raisc the cost largely for public standpipes, which are not highly ef-
:Of chemicals fivc to 10 tim~s.' Furthcrmorc, th~rc
thc fective in reducing morbidity and mortality from
is no way of knowing how long thcs~ ins~cticidcs will water-related diseases. It is well documented that con-
:remain 'toxic to thc mosquitocs. Among th~ mos- nections inside the house are necessary to encourage
:quitocsin which widcsprcad rcsistance to insecticidcs the hygienic use of water. so For example, shigella-
~ dcvclop~d arc Culex pipims fatigans,th~ major yec- caused diarrheas decreased 5 per cent with outside
~or of urban filariasis, and Aedes aegypti,thc vector of house connections but fell 50 per cent when sanitation
yellow fev~r and d~ngue.s and washing facilities were available within the
Two othcr vector-control programs illustrate thc home.sl
Drolong~d maintenance required by this type of hcalth All these estimates depend on exclusive use of
mtcrvcntion. Onchocerciasis, a potentially blinding protectcd sanitation and water supplies, without con-
ilelminth infection affecting 30 million people in tinuing use of environmental sources. In Bangladesh,
Inca, is bcing managed in the Volta River Basin for example, there was no reduction in cholera in
!Tough a 20-y~ar larvicide operation to control the areas supplied with tube wells, primarily because of
Ilackfly vcctor. The program is cstimated to cost $18 the use of contaminated surface water as well as the
~r capita for thc cntire 20-year period or $.90 pcr protected water supply." In St. Lucia, contact with
apita pcr year.2' Disability will be prcvcnted, and surface water could not be discouraged until house-
conomic activity in the arca may increase if the hold water supplies and then swimming pools and
Irogram is successful, but continuous, indefinite laundry units were installed, and an intensive health-
Ipplications of insecticide will be nec~ssary. Since education campaign was instituted.'2 In other words,
965, St. Lucia has had a program to control the changing peoples' habits in excretion and water usage
uail-transmitted helminth infcction schistosomiasis takes more than introducing an adequate, dependable
Lroughmolluscicides. An annual cost p~r capita of and convenient new source. Realistically speaking, a
971

7. 972 THE NEW ENGLAND JOURNAL Of MEDICINE Nov. I. 1979.
pervasive and effective health-education campaigns"s, patient clinics" and recently in the home's." to treat
is required. diarrheas of numerous causes.
These services could be provided by fixed units or
Nutrition Supplementation by mobile teams visiting once every four to six mont~
Nutrition programs have been advocated as among in areas where resources were more limited. Mobil~
the most efficient means of decreasing morbidity and units have been successfully used in immunization
mortality in children, but supplementation alone has programs for smallpox and measles,la.11 treatment
in
had no notable effect. Malnutrition is an underlying servicesdirected against African trypanosomiasis and;
or associated factor in many deaths from infections in meningitis"2 and in provision of child care in rural!
children; in a group of Latin American children, it areas.'}-8S
was associated in 50 per cent of the cases.s' Poor nutri- The cost of fixed units would be similar to that 0;
tion may also increase susceptibility to disease or basic primary health care, although efficienc;:y ShoUld
predispose an infccted child to more sevcre illness.60-42 be much greater. Cost estimates for a mobile health]
Conversely, infection may be a prominent cause of unit used in the model area in Africa for malaria con.1
poor nutrition".')'" since less food is ingested and ab- trol and water and sanitation programs werebasedOnJ
sorbed by a sick child. Therefore, if infections could be an extensive study of the Botswana health servicesby
controlled it is probable that the nutritional status of Gish and Walker."s They estimated $1.26 as the cost
children would improve greatly. There have been per patient contact in 1974, on a sample 306-km trip!
some situations, however, in which malnutrition has that reached 753 patients; the estimated cost per in.'
been reported to protect against certain infections, fant and child death averted was $200 to $250.1
e.g., the Sahel famine was thought to suppress Medications accounted for 30 to 50 per cent of th,
malaria, and iron deficiency was reported to protect cost, but this figure could be decreasedwith contrib~j
against bacterial infections."-'o tions of drugs from abroad or their manufacture!
In view of these findings, it is not surprising that few within the country. j
nutrition-supplementation programs alone have ef- Whether the system is fixed or mobile, flexibility is;
fected a major decrease in the death rate. The necessary.The care package can be modified at any;
Narangwal Project is one of these few, but even in that time according to the patterns of mortality and mor-:
program the cost per death averted in infants was bidity in the area served. Chemotherapy for intestinal;
1213. In children one to three years old the cost was helminths, treatment of schistosomiasis and sup-
$3000 -1.5 to three times higher than the cost of plementation with new vaccines or treatments as they!
medical care alonc.21 become available are all types of selective primary
health care that could be added or subtracted to t~
SelectivePrimaryHealthCare core of basic preventive care. It is important, however,~
The selective approach to controlling endemic dis- for the service to concentrate on a minimum number ,
ease in the developing countries is potentially the most of severe problems that affect iarge numbers of people;
cost-effective 'type of medical intervention. On the and for which interventions of established efficacy can
basis of high morbidity and mortality and of be provided at low cost.
feasibility of control, a circumscribed number of dis-
Research
easesare selected for prevention in a clearly defined
population. Since fewprograms based on this selective For a number of prevalent infections, treatment or
model of prevention and treatment have been at- preventive measures are expensive, difficult to ad-
tempted, the following approach is proposed. The minister, toxic or ineffective. These infections, which
principal recipients of care would be children up to include Chagas' disease, African trypanosomiasis,
three years old and women in the childbearing years. leprosy and tuberculosis, may better be dealt with
The care provided would be measles and diph- through an investment in research. In terms of the
theria-pertussis-tetanus (DPT) vaccination for chil- potential benefits, the cost of researchis low. Indeed,
dren over six months old, tetanus toxoid to all women the total amount now being spent on research in all
of childbearing age, encouragement of long-term tropical diseases is approximately $60 million, ex-
breast feeding, provision of chloroquine for episodesof ceedingly small in relation to the number of people in-
fever in children under three years old in areas where fected. As Table 4 shows,expenditures for researchon
malaria is prevalent and, finally, oral rehydration some of the major diseases in the developing world
packets and instruction. have by far the lowest per-capita cost of all medica! in-
If even50 per cent of the children and their mothers terventions discussed."
and 50 per cent of the pregnant women in a com- The estimated cost for the research and develop-
munity were contacted, deaths from measleswould be ment leading to the pneumococcalvaccine licensed in
expected to decrease at least 50 per cent,',.'2 deaths the United States in 1978 was $3 to $4 million
from whooping cough 30 per cent, ') from neonatal (Austrian R: personal communication). Death and
tetanus 45 per cent, '4 from diarrhea 25 to 30 per disability in developing countries would be reduced
cent's." and from malaria 25 per cent.' Oral rehydra- by heat-stable vaccines for measles,malaria, leprosy
tion has been used successfully in hospitals,"." in out- and rota virus and Eschenchia coli-induced diarrheas.

8. Vol. 301 No. 18 DISEASE CONTROL IN DEVELOPING COUNTRIES WALSH AND WARREN
adult population of the area covered by the service.As
the table suggests.selective primary health care may
be a cost-effective interim intervention for many less
developed areas.
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