J., and Warren, K. (1979). "Selective PHC -an interim         strategy for disease control in developing countries." The N...
Vol. 301     No    18       DISEASE     CONTROL         IN DEVELOPING          COUNTRIES     -WALSH       A:--D WARREN    ...
968                                                THE NEW ENGLAND JOURNAL                         OF MEDICINE            ...
Vol 301    No 18        DISEASE CONTROL         IN DEVELOPING     COUNTRIES           -WALSH       AND WARREN             ...
970                                THE NEW ENGLAND JOURNAL         OF MEDICINE                             Nov.   1979pcri...
Vol   301   No.   18   DISEASE CONTROL   IN DEVELOPING       COUNTRIES   -WALSH       AND WARREN      and the degree of im...
972                                THE NEW ENGLAND JOURNAL Of MEDICINE                                    Nov. I. 1979.per...
Vol. 301 No. 18                              DISEASE CONTROL                     IN DEVELOPING             COUNTRIES      ...
r                                                              HE NEW ENGLAND JOURNAL                      OF MEDICINE    ...
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1 selective phc interimstrategy

  1. 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 -974Walsh,
  2. 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 febrilefecting 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 oftality and feasibility of control. With these priorities in breast feeding in mothers. Other interventions mightmind 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 decencypoverty. level, they are important indicators of a vast~ate of collectiv,= ill health. The concomitant dis- How then, in an age of diminishing resources, canability 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 infanthealth 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 tovery scope makes it unattainable because of the cost show the rationale and need for instituting selectiveand numbers of trained personnel required. Indeed, primary health care directed at preventing or treatingthe 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 limited0~ 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. 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 lowthe highest priorities for prevention and treatment, morbidity associated with the infection, ascariasisfour 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 lowerof three representative illnesses of the less developed prevalence that that of ascariasis. Yet its mode ofworld. The newly discovered Lassa fever was as- transmission is well known, and it produces muchsociated with a 30 to 66 per cent mortality rate in the recurring illness and death; about one milliQnfew 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 andafter an illness lasting seven to 21 days. Although this ascariasis is that it can be controlled through regularfatality 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 mOSttreatment 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 Lassafever is impossible to control at present. Therefore, fever, ascariasis and malaria, the major infectionsconcentration on preventing Lassa fever would be endemic to the developing world (Table 1) wC!"tneither 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 dmost prevalent infection of man, with one billion cases major importance, and rank may change or items maythroughout the world.7 Yet disability appears to be be added or deleted, depending on the geographicminor 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 notperiod.)." 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..INECTION l"nc-no1S 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...aIUTTfDiarrheas !-5,OOO,000 5-10,000 3-5,CXXJ,CXXJ 3-S 2Respiratory inrcctions 4-SOOO 5-7 2-3Malaria 800,000 1200 1SO,CXXJ 3-S 2Measles 85,000 900 80,CXXJ I~I~ 2Schist~omiasis 200,000 500-1 000 20,CXXJ 6(»-1 (XX) 3-4Whooping cough 70,000 2s0..450 2O,CXXJ 21-28 2Tuberculosis 1,000.000 400 7CXXJ 200-400 3NeonatalteLanus 120-180 100-150 120-180 7-10 IDiphtheria 40,000 ~ 700-900 7-10 3Hookworm 7-900,000 S(}-6() 1500 100 4South American trypan- 12,000 60 1200 600 2 osomiasisOnchocerciasis Skin disease Low :CJ.~:- 2 -)XX) 3M ---3 3O,CXXJ River blindness 20-50 200-500 J<XX! 1-2Meningitis I SO 30 ISO 7-10 1Amebiasis 400,CXXJ 30 1500 7-10 3Ascariasis 800,OOO-I,CXXJ,OOO 20 I<XX> 7-10 3Poliomyelitis 80,000 10-20 2<XX> J<XX!+ 2Typhoid 1000 25 500 14-28 2leishmaniasis 12,000 5 12. <XX> I100-200 3Arrican trypanosomiasis 1000 10 ISO Ileprosy Very low 12.<XX> 5OQ-J<XX! 2-:Trichuriasis 500,000 Low 100 7-10 ,Filariasis 2SO,OOO Low 2- )<XX) 1000 3Giardiasis 200,000 Very low 500 5-7 JDengue 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«) fIU« du nol .1.." m..ch ,h.". ofT.:i.lly rCOrtcd. b..: .""rrcpo"",rc.. I dcno,c, bcdr,ddcn. 2 .blc 10 I.nc"on on own ° ".., c"C. ..,mo.t.,or) " ..m,no,
  4. 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 PRORrn REASONS ro. ASSGN"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!difrocultr 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. 5. 970 THE NEW ENGLAND JOURNAL OF MEDICINE Nov. 1979pcriods to cnsure cure.4.22.23In~tcad of attempting im- poor in developing countries by the year 2000 will b6mcdiate, large-scale trcatment programs for these in- $5.4to $9.3 billion (in 1975 prices).26This investmentjfections, the most efficient approach may be to invest which includes only initial capital investment andin rcsearch and developmcnt of lcss costly and morc training costs, would provide one community healtefficacious 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 tpriorities 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 estimateuldiseases 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 ale 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 servicestions relevant to the worlds developing areas that are and development of communication, transportationconsidered below are comprehensive primary health and administrative networks to supply and managecare (which includes general development as well as the health facilities. Furthermo~, the effectivenessofall systems of disease control), basic primary health this model program for averting deaths or applyingcare, multiple disease-control measures (e.g., insec- such preventive measures as education in sanitationticides, 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-carewith 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 oBSaharan Africa will be used: the birth rate is 46 per child care.21.2. ithousand total population, the crude de3th rate 19 per The cost and effectiveness of several experimentthousand 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, Nigeria2Comprehensive 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 pedthe best available means of conquering global dis- capita varied widely among the programs, partiCUlease, 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 servicthis system encompasses development of all segments to their communities. In general, however, the cosof the economy, ready and universal access to curative per capita ranged between 1 and 2 per cent of thCJcare, prevention of endemic disease, proper sanitation national per capita income of the particular countrvJand safe water supplies, immunization, nutrition, The cost for infant deaths averted were difficult rhealth 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 $20,000, with a media ~ 1hensive primary health care to everyone in the near fu- of 1700. The only precise calculations for the costs peture remains unlikely. infant death averted ($ 144) or child death averte Basicprimary health-care systems are far more cir- (1988 per one to three-year-old child) were forcumscribed 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 mucwithin 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 basitht: cost of furnishing basic health services to all the primary health care have been successful,but the cos
  6. 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 cent2.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, a971
  7. 7. 972 THE NEW ENGLAND JOURNAL Of MEDICINE Nov. I. 1979.pervasive and effective health-education campaigns"s, patient clinics" and recently in the homes." to treatis 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.}-8Swas 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 ShoUldpredispose 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 werebasedOnJsorbed by a sick child. Therefore, if infections could be an extensive study of the Botswana health servicesbycontrolled 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 $250.1e.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 canbasis of high morbidity and mortality and of be provided at low cost.feasibility of control, a circumscribed number of dis- Researcheasesare selected for prevention in a clearly definedpopulation. Since fewprograms based on this selective For a number of prevalent infections, treatment ormodel 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, whichprincipal 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 withThe care provided would be measles and diph- through an investment in research. In terms of thetheria-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 allof 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 researchonmalaria is prevalent and, finally, oral rehydration some of the major diseases in the developing worldpackets 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 inexpected to decrease at least 50 per cent,,.2 deaths the United States in 1978 was $3 to $4 millionfrom whooping cough 30 per cent, ) from neonatal (Austrian R: personal communication). Death andtetanus 45 per cent, 4 from diarrhea 25 to 30 per disability in developing countries would be reducedcents." and from malaria 25 per cent. Oral rehydra- by heat-stable vaccines for measles,malaria, leprosytion has been used successfully in hospitals,"." in out- and rota virus and Eschenchia coli-induced diarrheas.
  8. 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. REFERENCES I. World Health Organization: Declaration or Alma Ata (Repon on the International Conrerence on Primary Health Care, Alma Ata, USSR, September 6-12, 1978). Geneva, World Health Organiution. 1978 2 McNamara RS: Address to the Board or Governon orthe World Bank. Washington, DC, World Bank, 1978 3. Geographic Medicine ror the Practitioner: Algorithms in the diagnosis and management or exotic diseases. Edited by KS Warren, AAF by improved chemotherapy for leprosy, tuberculosis, Mahmoud. Chicago, Univenity or Chicago Press. 1978 American and African trypanosomiasis, onchocercia- ~. Tropical Medicine. Edited by GW Hunter III, JC Swanzwelder, DF sis and filariasis and by depot drugs for malaria and Clyde. Firth edition. Philadelphia, WB Saunden Company, 1976 5 Resistance or Vecton and reservoirs or disease to pesticides: twenty-sec- intestinal helminths. ond repon or the WHO Expen Committee on Insecticides. WHO Tech Rep Ser 585:1-88, 1976 CONCLUSIONS 6. Yirallnrections or Humans: Epidemiology and control. Edited by AS Evans. New York, Plenum Medical Book Company, 1976 Until comprehensive primary health care can be 7. Peters W: Medical aspecu -comments and discussion II, The Rele- made available to all, services aimed at the few most vance or Parasitology to Human Welrare Today (Symposia or the British Society ror Parasitology. Yol 16). Edited by ERA Taylor, R important diseases (selective primary health care) Muller. Oxrord. Blackwell Scientific Publications, 1978, pp 2~1 may be the most effective means of improving the 8. Arfaa F, S.hba GH, Farahmandian I: Eovaluation or the effect of dif- health of the greatest number of people. 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The inadequacy of avail- a community at Panyogoro. Trans R Soc Trop Med Hyg 66835-851, 1972pble data makes it impossible to measure distinct and 13 Farooq M, Samoan SA. Nielsen T Assessment or severity or disease!undeniable secondary benefits. For example, water caused by Schurosoma hat_tobium and S. ",anso,,; in the Egypt-49:supplies close by would savetime for the women who project area. Bull WHO 35:389-404, 1966 I~. Siongok TKA, Mahmoud AAF, Ouma JH, et al: Morbidity inprry water. and increased amounts could irrigate a Schutosomiasis "an.rOlli in relation to intensity or inrection: study of afome garden. community in Machakos. Kcnya. Am J Trop Med Hyg 25:273-284,r Accordingly, Table 5 summarizes the estimated 1916 15. Hull TH, Rohde JE: Prospecu for Rapid Decline or MonaJity Rates in~ ts per capita and per death averted for the various Java: A study or causes or death and tbe reasibility or poliey interven- ealth interventions considered. 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