Objective: To analyze the prevalence of asthma and asthma symptoms in students of two distinct age brackets residing in the city of Tangará da Serra, Brazil. Methods: Cross-sectional, population-based study of the prevalence of asthma in children from 6 to 7 years of age and adolescents from 13 to 14, using the standardized International Study of Asthma and Allergies in Childhood, phase 1 questionnaire, validated for use in Brazil. Students who responded affirmatively to question 2 (presence of wheezing in the preceding 12 months) were classified as suffering from asthma. Results: The study comprised 3,362 students, of whom 1,634 (48.6%) were children and 1,728 (51.4%) were adolescents. Of the 1,634 children, 816 (49.9%) were male and 818 (50.1%) were female. Of the 1,728 adolescents, 773 (45.0%) were male and 955 (55.0%) were female. The prevalence of asthma among the children was 25.2%, whereas that among the adolescents was 15.9% (χ2 = 8.34; p = 0.00). The children presented higher prevalences of the following symptoms of asthma than did the adolescents: wheezing ever (54.3%), nocturnal dry cough (43.9%), wheezing in the preceding 12 months (25.2%), and from 1 to 3 attacks of wheezing in the preceding 12 months (19.1%). There were no differences between the two groups regarding physician-diagnosed asthma (approximately 4.5%). There were no statistical differences regarding the prevalence of asthma by gender in the two groups. Conclusions: Tangará da Serra has a high prevalence of asthma in children and adolescents, and this result is compatible with other studies carried out in Brazil and Latin America using the same methodology.

Keywords: Asthma/epidemiology; Child; Adolescent.

Objective: To analyze hospitalizations for respiratory diseases among children under 15 years of age in an area with high levels of environmental pollution. Methods: A cross-sectional study of hospitalizations due to respiratory diseases of patients residing in the city of Tangará da Serra, located in the state of Mato Grosso (Brazilian Amazon region), from 2000 to 2005. Data on hospital admissions were obtained from the Brazilian Unified Health Care System and from Brazilian Institute of Geography and Statistics population estimates. Results: In 2005, the rate of hospitalization for respiratory diseases among children under 15 years of age in the microregion of Tangará da Serra was 70.1/1,000 children. Between 2000 and 2005, there were 12,777 such admissions, of which 8,142 (63.7%) were for respiratory diseases. During the dry season (May to October), the rate of admissions for respiratory diseases was 10% higher than during the rainy season (November to April). The principal causes of admission included pneumonia (90.7%) and respiratory insufficiency (8.5%). Admissions of children under 5 years of age for pneumonia were 4 times the expected number for the city. Children under 12 months of age were the most frequently hospitalized, with an average increase of 32.4 admissions per 1,000 children per year. Conclusions: Tangará da Serra presented a high number of pediatric admissions for respiratory diseases. Therefore, it is logical to consider it a priority area for investigation and monitoring of the environmental risk factors for such diseases.

Keywords: Respiratory tract diseases; Pneumonia; Hospitalization; Climate; Air pollution/Brazil.

Objective: To analyze the effectiveness of the Tuberculosis Control Program, in conjunction with the recently incorporated Family Health Program, in the city of Cáceres, Brazil, between 1999 and 2004. Methods: This was a descriptive epidemiological study, based on the registry of tuberculosis cases diagnosed and treated in Cáceres, according to the characteristics of the cases diagnosed, whether or not the protocol for diagnosis, treatment, and monitoring of patients was followed, as well as the type of health care facility involved. Results: The incidence of tuberculosis was reduced from 99.4 to 49.8 (per 100,000 inhabitants) between 1999 and 2004. The patients presented characteristics similar to those of patients from other regions of Brazil, with a predominance of males during their most economically productive years. Among the patients presenting pulmonary forms and treated via the Family Health Program, there was a reduction in the number of sputum smear microscopies performed at the moment of diagnosis (OR = 0.33; 95%CI: 0.16-0.66) and prior to discharge (OR = 0.32; 95%CI: 0.18‑0.59). The patients monitored via the Family Health Program presented a 16.4% lower cure rate than did those treated at the referral center, as well as being more likely to abandon treatment (OR = 2.93; 95%CI: 1.15-7.46) and to die (OR = 5.71; 95%CI: 1.85‑18.1). Conclusion: The decentralization of the treatment services to the family health clinics did not improve the treatment or monitoring of tuberculosis cases in the city of Cáceres.

Keywords: Tuberculosis/epidemiology; Community Health Services; Health care reform/Brazil.

Objective: To evaluate surveillance of contacts of new tuberculosis cases in the state of Mato Grosso from 1999 to 2004. Methods: This was a descriptive epidemiological study based on data from the Tuberculosis Case Registry Database. The number of new tuberculosis cases, the number of contacts (estimated, investigated, and uninvestigated), and the tuberculosis incidence rate were analyzed by age bracket. The mean rate of contacts investigated for each case of tuberculosis by age bracket was calculated per year of study. The cases of pulmonary tuberculosis with and without contacts investigated were analyzed by sputum smear microscopy results. Results: In 2004, there were 41.3 cases of tuberculosis per 100,000 inhabitants in the state of Mato Grosso. The south-central region presented the highest incidence rate (57 cases/100,000 inhabitants) and a 15% rate of contacts investigated. Among those younger than 15 years, 63 contacts (60.5%) were investigated, whereas among those aged 15 or older, 389 (8.9%) were investigated. In 1999, the mean rate of contacts investigated statewide was 0.02 (0.5%), and, in 2004, it reached 0.42 (10.5%). The percentage of contacts investigated was 40% higher among the contacts of contagious cases (OR = 1.4; 95% CI: 1.08-1.83). Conclusions: The percentage of contacts investigated is very low, principally among adults. The adoption of the standards for investigation of tuberculosis contacts proposed by the Brazilian National Ministry of Health Department of Health Surveillance has not ensured that this group at highest risk of developing active tuberculosis be given priority at health care facilities in the state of Mato Grosso.

Keywords: Contact tracing; Epidemiologic surveillance; Tuberculosis/prevention & control.