
Vol. 16, No. 4	December 1995

ACUTE RESPIRATORY INFECTIONS IN THE AMERICAS

Introduction

Current Situation

Mortality

Morbidity

Quality of Care

Objectives of ARI Control

Strategies

Bibliography

Introduction

Since the mid-1960s acute respiratory infections (ARI) have been recognized as one of the three most important problems affecting child health, together with diarrheal diseases and malnutrition. In terms of both mortality and morbidity, ARI have been among the five leading causes of death, physician consultations, and hospitalization in children under 5 in all the developing countries.

With the strides made in the control of diarrheal disease in most of these countries since the mid-1980s, ARI became the leading cause of death in children under 1 year of age and in children 1 to 4. Even in the developing countries recording the lowest total mortality rates in these age groups, ARI were the third leading cause of death in children under 1, followed by diseases originating during the perinatal period and birth defects. They were also the second leading cause of death in children aged 1 to 4, after accidents.

Beginning in this period, ARI control became a real challenge for most of the developing countries, as health care activities became targeted to reducing the leading causes of mortality and morbidity in children under 5.

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Current Situation

There are four important aspects in the analysis of the ARI problem and, as a result, the design of control measures: mortality, morbidity, quality of care, and the prevalence of risk factors.

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Mortality

Pneumonia represents the leading cause of mortality for the diseases grouped under ARI and is responsible for 85% of the total deaths from these causes. For this reason, most of the information available for the analysis of ARI as a cause of mortality concerns pneumonia. However, other ARI diagnoses (influenza, bronchitis, bronchiolitis) are occasionally included in the analysis, due to the general deficiency in the information on mortality from specific causes, especially when the information concerns young children in developing countries.

These certification problems add on to the existing problems related to the quality of the total mortality figures for the developing countries of the Americas--problems that are exacerbated in the recording of deaths in children under 5 years of age.

Available PAHO estimates indicate that mortality from ARI in children under 5 (including pneumonia, influenza, bronchitis, and bronchiolitis) ranges from 16 deaths per 100,000 live births in Canada to 3,072 in Haiti (Table 1). Haiti is a country in which ARI represent from 20% to 25% of total deaths: that is, 1 out of every 4 deaths in children under 5 is due to ARI.

Most of the developing countries in the Americas, naturally, have lower ARI mortality rates. However, there is a marked gap between the developed countries of the Region (Canada, the United States) and the developing countries. Even Costa Rica or Cuba, which have the lowest mortality rates of the developing countries of the Region, report values seven times higher than those of Canada.

The highest percentage of these deaths from ARI occur in children under 1 year of age and are due to pneumonia and influenza. The available PAHO estimates on these causes show a marked difference in mortality in children under 1 year of age, ranging from 8 deaths per 100,000 live births in Canada to 2,352 in Haiti (Table 1). The differences between mortality from pneumonia and influenza in children under 1 are also very marked in the developing countries of the Region.

Table 1 Estimated Mortality Rate in Children Under 5 Years of Age Total Deaths and Deaths Due to ARI and Pneumonia and Influenza (Circa 1994)

	Deaths Under 5 Years		Deaths Under 1 Year
Country	Total	ARI	Total	Pneumonia and Influenza
Argentina Bahamas Barbados Belize Bolivia Brazil Canada Chile Colombia Costa Rica Cuba Dominican Republic Ecuador El Salvador Guatemala Guyana Haiti Honduras Jamaica Mexico Nicaragua Panama Paraguay Peru Puerto Rico Saint Kitts and Nevis St. Vincent and the Grenadines Saint Lucia Suriname Trinidad and Tobago United States Uruguay Venezuela	30 21 19 46 100 67 8 17 42 14 12 62 62 56 81 62 128 73 23 37 64 27 56 83 14 32 23 23 40 22 10 22 31	150 168 114 368 1,500 804 16 238 546 112 108 558 1,054 392 1,215 620 3,072 657 253 555 960 162 1,288 2,573 42 256 138 161 320 264 30 176 248	26 19 16 36 74 57 7 14 32 12 10 48 44 43 51 46 98 44 17 30 53 21 42 59 12 27 18 19 31 17 8 19 26	117 154 85 688 1,480 467 8 227 358 119 82 245 392 176 903 345 2,352 264 139 450 504 116 563 1,251 79 95 61 72 171 143 14 80 161

Note: ARI (comprises ICD-9 codes 460-466 and 480-487); pneumonia and influenza comprises ICD-9 codes 480-487

Clarifications:

The estimates of infant mortality rate and the rate in children under 5 were made by PAHO. Health Situation Analysis Program. Division of Health and Human Development.

Mortality from ARI in children under 5 was calculated on the basis of mortality estimates in children under 5 and the percentage of deaths recorded from ARI in the same group for the latest available year between 1988 and 1993.

Mortality from pneumonia and influenza in children under 1 was calculated on the basis of PAHO infant mortality estimates and the percentage of deaths recorded from pneumonia and influenza in the same group for the latest year available.

The estimates that have been made, however, show large differencesfrom the figures officially reported by some of the countries of the Region (Table 2). Except in the case of Belize, where there is an eightfold difference between the estimate and the last reported rate for the country, and the case of Peru, where there is a threefold difference, in the rest of the countries the information from official records yields mortality rates that are less than half of the rates generated by the estimates.

Thus, the description of mortality from pneumonia and influenza in the Region, based on information collected systematically by the countries, turns out to be limited, which is the reason why the estimates present a picture that is closer to reality.

Table 2 Mortalidad from Neumonia and Influenza in Children Under 1 Year of Age, in Selected Countries of the Americas* (Estimated and Official Figures)

	Mortality from Neumonia and Influenza
	Estimates(*)	Official Information(**)
Country	Rate	Year	Rate
Argentina Bahamas Barbados Belize Bolivia Brazil Canada Chile Colombia Costa Rica Cuba Dominican Republic Ecuador El Salvador Guatemala Guyana Haiti Honduras Jamaica Mexico Nicaragua Panama Paraguay Peru Puerto Rico Saint Kitts and Nevis St. Vincent and the Grenadines Saint Lucia Suriname Trinidad and Tobago United States Uruguay Venezuela	117 154 85 688 1,480 467 8 227 358 119 82 245 392 176 345 903 2,352 264 139 450 504 116 563 1,251 79 95 61 72 171 143 14 80 161	1991 1987 1991 1989 ... 1989 1991 1991 1991 1991 1990 1985 1990 1991 1984 1984 ... ... 1985 1991 1991 1989 1988 1989 1991 1985 ... 1988 1990 1991 1991 1990 1989	99 231 95 73 ... 349 8 195 159 88 88 375 296 116 1,007 270 ... ... 185 267 394 68 493 279 59 98 ... 55 84 103 15 97 128

... Data not available
(*) Circa 1994
(**) The official information to the latest year available sent by the country
Source: Health Situation Analysis Program, Division of Health Human Development

In addition to recording high mortality from pneumonia and influenza, in a large number of developing countries decreases in these rates have not been seen in recent years. Comparing the 1985 estimates with the 1994 estimates (Table 3), it can be seen that in several countries the estimates have turned out to be higher for 1994 than for 1985, and in others, the differences between these rates are less than 20%, representing an annual reduction rate of less than 3%.

The large difference between mortality from pneumonia and influenza in the developed and the developing countries is even greater if one considers the fact that both Canada and the United States lowered their rates by 20% or more during the period from 1985 to 1994 (20% and 26.3% respectively). Thus the distance separating the two groups of countries increased in 1994.

Table 3 Percent Decline in Mortality from Pneumonia and Influenza in Selected Countries of the Americas, 1985 and Circa 1994

	Mortality from Pneumonia and Influenza*
Country	1985	Circa 1994	Percent Decline
Argentina Barbados (1) Belize (2) Canada Chile Colombia Costa Rica Cuba Dominican Republic Ecuador El Salvador Guatemala Jamaica Mexico Nicaragua Panama Paraguay Peru Puerto Rico Trinidad and Tobago United States Uruguay Venezuela	134 92 424 10 304 243 142 169 375 439 140 1,207 136 436 300 90 587 1,924 85 91 19 90 155	117 85 688 8 227 358 119 82 245 392 176 903 139 450 504 116 563 1,251 79 143 14 80 161	12.69 7.61 -62.26 20.00 25.33 -47.33 16.20 51.48 34.67 10.71 -25.71 25.19 -2.21 -3.21 -68.00 -28.89 4.09 34.98 7.06 57.14 26.32 11.11 -3.87

(1) 1984
(2) 1986
* Estimates

The causes that explain the observed differences are doubtless complex and include considerations that not only relate to the health area. In order to generate a systematic analysis, however, it is feasible to attribute these differences to the following factors:

The difficulty of access to health services, resulting in a large number of household deaths of children who do not receive care from health personnel. The lack of access of the population to health services, and the lack of enough antibiotics for early treatment are some of the factors commonly associated with these deaths.

The inadequate quality of the care provided by many health service agencies, indicated by the lack of standardized criteria for the early detection of the warning signs of pneumonia by health personnel and the community.

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Morbidity

Studies carried out on the annual incidence of ARI episodes in children under 5 years of age have included that this incidence is similar in both developed and developing countries. In all studies it was observed that on average a child less than 5 years old living in an urban area suffers between six and eight ARI episodes annually, including cough, cold, rhinorrhea, bronchitis, bronchiolitis, pneumonia, etc. The studies carried out in rural areas yielded a smaller rate of incidence, estimated at four to six ARI episodes annually. The factors related to this difference may be attributed to the reduced concentration of environmental pollutants that irritate the mucous membranes of the respiratory tract.

In contrast, a marked difference in the incidence of pneumonia has been observed between the eveloping countries and the developed countries, where this indicator can reach a level of between 150 and 200 pneumonia episodes per 1,000 children per year. In addition, differences have been found in the etiology of these cases: whereas they were predominantly bacterial in the developing countries, there was a high prevalence of viral pneumonias in the developed countries.

The high incidence of pneumonia, added to the prevalence of risk factors in children (malnutrition, overcrowding, low level of care provided to children in the home), means that in the developing countries, the incidence of complications in pneumonia cases is much more frequent than in the developed countries, and the mortality rates are correspondingly higher. The following risk factors stand out: low birthweight, the lack or short duration of breast-feeding, malnutrition and the lack of vitamin A, the lack of vaccinations or incomplete vaccinations, air pollution in the home, and drops in temperature. In these cases pneumonia becomes an associated risk factor that increases the probability of death or serious disease in the child.

The availability of information in the Region on morbidity at the country level is limited and the factors affecting the quality of information on mortality are also present, aggravated by the absence of a system to collect data and perform a systematic analysis on the data that already exists on mortality.

However, the data available from special studies shows a similar morbidity profile as that recorded in the health service agencies. This profile reflects the high incidence of ARI in children (representing between 40% and 60% of pediatric consultations in the health service agencies), and the low relative weight of pneumonia in the total consultations for ARI (less than 10% in most of the studies).

On the other hand, the information obtained from hospital records yields a higher relative weight for neumonia, given that it is one of the leading causes of hospitalization from ARI in children, along with cases of severe bronchial obstruction. In most hospitals in the developing countries, ARI represent between 20% and 40% of all pediatric hospitalizations. Most of these hospitalizations are due to pneumonia, and a smaller percentage to bronchitis, bronchiolitis and bronchial obstruction syndrome.

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Quality of Care

Although the quality of care received by children under 5 in the health service agencies was already mentioned as one of the factors relating to high mortality, this element also has an impact on a very important problem for the control of ARI: the use of medications in treatment.

ARI are the leading cause of antibiotic administration in children under 5 years of age. In most of the studies conducted, 50% or more of ARI cases treated in the health service agencies received antibiotics as treatment, despite the fact that most of these cases did not require them. The improper use of antibiotics promotes bacterial resistance and can produce potentially harmful effects on the health of the child.

In addition to antibiotics, other unrecommended drugs are used to treat ARI in children, such as cough and cold syrups, many of which contain substances that are potentially harmful as a result of their role in suppressing the child's natural defense mechanisms.

The management of ARI cases that do not present signs of severity or pneumonia does not require the administration of antibiotics or other drugs. The outpatient management of these cases can be conducted by treating the symptoms. Syrups and other drugs that are used for cough and cold, in addition to being expensive, contain combinations of different drugs that sometimes have contrary or adverse effects, and which can turn out to be harmful to the child.

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Objectives of ARI Control

The PAHO/WHO Regional ARI Control Program has proposed two principal objectives, based on the magnitude of the problem in the developing countries of the Americas and the availability of strategies for their achievement:

The reduction of mortality from pneumonia in children under 5; an objective that is basically intended to:

Prevent deaths associated with the lack of adequate care provided to children by health personnel (failure to detect warning signs, failure to administer antibiotics to children who need them).
Prevent deaths associated with late consultations to health facility (failure of mothers and other caretakers to identify warning signs).
Prevent deaths in the home resulting from a failure to consult a health facility (inadequate access of the population to health care providers).

The reduction of the use of antibiotics and other drugs for ARI treatment in children under 5; this objective is intended to:

Prevent the administration of antibiotics to children who are seen for cough, cold, grippe, bronchitis or non-streptococcal pharyngitis.
Prevent the administration of syrups for cough and cold that contain drugs that are potentially harmful to the child.
Discourage the self-administration of antibiotics as treatment for ARI by mothers and other members of families with children under 5.

In addition to the above, the Regional Program has proposed two additional objectives:

The reduction of the frequency of complications from acute upper respiratory infections:

Reduce the incidence of deafness or hypoacusis due to the poor management of otitis media episodes.
Reduce the incidence of rheumatic fever in children that is associated with the failure to administer antibiotics in cases with streptococcal pharyngitis.

The reduction of the incidence and severity of acute lower respiratory infections:

Reduction of the incidence of pneumonia associated with measles and whooping cough.
Reduction of the incidence of risk-increasing factors: low birthweight, malnutrition, failure to breast-feed, indoor air pollution.