Infectious and Chronic Diseases
Perinatal conditions were responsible for 47.1 percent of total infant mortality, ranking first among the causes of reported deaths for those under one year old in 1988. The leading cause of mortality among children one to four years of age, at 24.5 percent of all deaths in 1988, was infectious and parasitic diseases, particularly diarrheal diseases. External causes, specifically traffic accidents and homicide, accounted for the greatest share of registered deaths for the cohort aged five to forty-nine. Among the elderly population sixty years and above, deaths resulting from diseases of the circulatory system amounted to the highest percentage (50.3) of the total in 1989. Those diseases were also the leading cause of mortality for the entire nation, with higher ratios in the wealthier Southeast (36.2 percent) and South (37.2 percent), relative to the impoverished North (23.2 percent) and Northeast (29.3 percent). Although the proportion of deaths has shifted to older population groups, regional variations continue to hold, such that over a quarter of deaths afflicts the below-five age range in the North.
Expanded immunization coverage in recent years has favored a drop in mortality ascribed to vaccine-preventable diseases, from 12.9 percent in 1979 to 2.4 percent in 1988. In 1993 vaccination of Brazilian children less than one year old under the National Immunization Program reached 68.5 percent for diphtheria, pertussis, and tetanus, 92.3 percent poliomyelitis, 77.7 percent measles, and 98 percent tuberculosis. Although tuberculosis persists as a principal source of morbidity and mortality, particularly with the onset of the human immunodeficiency virus (HIV), its incidence and death rates have been steadily on the decline.
Control measures have proven effective in reducing the prevalence and outbreak of other infectious and endemic diseases, including cholera, Chagas' disease (American trypanosomiasis), yellow fever, and schistosomiasis (bilharzia). However, the number of registered cases of malaria, which 42.9 percent of the Brazilian population is at risk of contracting (mainly in the Amazon region), grew from 52,000 cases per year in 1970 to about 600,000 in the 1980s, with some improvement since then. Other communicable diseases either have been reintroduced, as in the case of dengue (breakbone fever) since 1986. Infectious tropical diseases reflect poor sanitary conditions as well as discrepancies in the standard of living between Northern and Southern Brazil, where such diseases ranked third and last, respectively, among the six leading causes of death in 1989.
Leprosy remains a serious problem in Brazil's high poverty areas, where the disease is spreading most rapidly. In October 1996, an average of 100 new cases were being reported each day. As many as half a million Brazilians are afflicted with leprosy.
The incidence of acquired immune deficiency syndrome (AIDS) in Brazil has also reached epidemic proportions, from 490 in 1985 to 103,262 cumulative cases by March 1, 1997, the fourth highest reported prevalence in the world. Based on 1996 data from the Pan American Health Organization (PAHO), homosexuals and/or bisexuals constitute 45 percent of the cumulative cases; intravenous drug users, 27 percent; heterosexuals, 20 percent; and others, 8 percent. The incidence was highest among young adults; 60 percent of those suffering from AIDS in 1994 were in the twenty-five to thirty-nine age-group. What began as a disease of homosexuals and recipients of blood transfusions quickly spread to heterosexuals and intravenous drug users. HIV infection attributed to needle-sharing during drug use increased from 3.0 percent of the cases in 1986 to 24.5 percent in 1992-93 and from 5.0 percent to 23.4 percent for heterosexual transmission, altering the male-to-female ratio from 100:1 in the 1980s to 4:1 in 1994. The surge in the proportion of women contracting the virus has resulted in part from a rise in perinatal transmission, the predominant mode of infection for the 12,000 infants and children diagnosed with AIDS in 1994.
The overall reduction in the number of new cases of the above infectious diseases, on the one hand, and the conspicuous rise in the incidence of chronic and degenerative diseases, on the other, indicate the occurrence of an epidemiological transition in Brazil. However, the transition is not complete; the two types coexist as major causes of death. Diseases of the circulatory system, including cerebrovascular and heart diseases, currently claim first place as the leading cause of death among the entire population (34.3 percent in 1989). The degenerative diseases have contributed to steep rises in the cost of health care, especially for the elderly.
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