In March of 2009, a flu epidemic began in Mexico. Shortly thereafter, similar cases appeared in other countries, alerting authorities to the risk of a pandemic. This article details the principal signs and symptoms of infection with the swine-origin Influenza A (H1N1) virus. In addition, the measures to be taken in suspected or confirmed cases are addressed, as are the procedures to follow in relation to contacts. Furthermore, the drugs used in the prophylaxis against and the treatment of infection with the H1N1 virus are described.

Keywords: Influenza A virus, H1N1 subtype; Influenza A virus; Disease outbreaks.

In view of the pandemic caused by a new virus, influenza A (H1N1), we report the case of a 56-year-old patient without relevant risk factors and with severe acute respiratory syndrome resulting from infection with this virus. We present the results of laboratory tests and the imaging findings (chest X-ray and CT scans). The evolution was favorable, and the patient was discharged after 14 days.

Keywords: Influenza A virus, H1N1 subtype; Severe acute respiratory syndrome; Patient care.

Objective: To describe aspects found on HRCT scans of the chest in patients infected with the influenza A (H1N1) virus. Methods: We retrospectively analyzed the HRCT scans of 71 patients (38 females and 33 males) with H1N1 infection, confirmed through laboratory tests, between July and September of 2009. The HRCT scans were interpreted by two thoracic radiologists independently, and in case of disagreement, the decisions were made by consensus. Results: The most common HRCT findings were ground-glass opacities (85%), consolidation (64%), or a combination of ground-glass opacities and consolidation (58%). Other findings were airspace nodules (25%), bronchial wall thickening (25%), interlobular septal thickening (21%), crazy-paving pattern (15%), perilobular pattern (3%), and air trapping (3%). The findings were frequently bilateral (89%), with a random distribution (68%). Pleural effusion, when observed, was typically minimal. No lymphadenopathy was identified. Conclusions: The most common findings were ground-glass opacities and consolidations, or a combination of both. Involvement was commonly bilateral with no axial or craniocaudal predominance in the distribution. Although the major tomographic findings in H1N1 infection are nonspecific, it is important to recognize such findings in order to include infection with the H1N1 virus in the differential diagnosis of respiratory symptoms.

Keywords: Pneumonia, viral; Tomography, X-ray computed; Influenza A virus, H1N1 subtype.

Objective: To evaluate pandemic influenza A (H1N1) 2009 in hospitalized patients in order to identify risk factors for hospitalization and, consequently, for the worsening of the disease. Methods: This retrospective observational study was conducted between March and December of 2010. The data were collected from the Brazilian Ministry of Health National Case Registry Database. We included only patients (inpatients and outpatients) in whom H1N1 infection was confirmed (via laboratory testing) during the study period. The variables regarding demographic and clinical characteristics were statistically evaluated in order to compare the hospitalization rates in the presence or absence of these factors. Risk factors were identified by logistic regression analysis. Results: We included 4,740 patients with laboratory confirmation of H1N1 infection. Of these, 1,911 individuals were hospitalized, and 258 (13.5%) died. The risk factors for hospitalization were age (20-29 years), African or Indigenous ethnicity, presence of specific comorbidities (heart disease, lung disease, kidney disease, hemoglobinopathy, immunosuppression, diabetes, obesity, puerperium, and smoking), a high number of comorbidities, and specific symptoms (dyspnea, diarrhea, vomiting, chest pain, hemoptysis, pneumonia, and wheezing). Higher levels of education and early use of oseltamivir were found to be protective factors. Hospitalization contributed to an increase in survival. Conclusions: Knowledge of the epidemiological characteristics that can be associated with hospitalization, disease severity, and mortality can be helpful in the adoption of preventive measures, as well as in the early diagnosis and treatment of disease, which might contribute to the reduction in the numbers of hospitalizations and deaths.

Keywords: Influenza A virus, H1N1 subtype; Hospitalization; Risk factors; Oseltamivir.

In 2010, 96 patients suspected of being infected with the influenza A (H1N1) virus were hospitalized at the Hospital São Paulo, located in the city of São Paulo, Brazil. Of those 96 patients, 4 (4.2%) were found to be infected with influenza A virus-3 with influenza A (H1N1) and 1 with seasonal influenza A-and 2 patients (2.1%) were found to be infected with influenza B virus. Most (63.5%) of the suspected cases occurred in children, as did half of the positive cases. The second wave of influenza A (H1N1) infection was weaker in São Paulo. The decrease in the number of hospitalizations for H1N1 infection in 2010 might be attributable to vaccination.

Keywords: Influenza A virus, H1N1 subtype; Influenza, human; Pneumonia; Pandemics.

Objective: To describe the characteristics of patients with influenza A (H1N1)-associated pneumonia treated at two hospitals in the region of Liguria, Italy, as well as to describe their treatment and outcomes. Methods: This was a prospective observational study including all patients older than 16 years of age with a confirmed diagnosis of influenza A (H1N1) who were admitted to Villa Scassi Hospital, in the city of Genoa, Italy, or to the Sestri Levante General Hospital, in the city of Sestri Levante, Italy, between September of 2009 and January of 2010. The primary outcome measure was mortality within 60 days after diagnosis. Secondary outcome measures were the need for mechanical ventilation and the length of hospital stay. Results: Of the 40 patients with a confirmed diagnosis of influenza A (H1N1), 27 presented pneumonia during the study period. The mean age of the 27 patients was 42.8 ± 14.8 years, and the mean length of hospital stay was 11.6 ± 8.2 days. Of the 27 patients, 20 had respiratory failure, 4 underwent invasive mechanical ventilation, and 5 underwent noninvasive ventilation. One patient had comorbidities, developed multiple organ failure, and died. Conclusions: During the influenza A (H1N1) pandemic, the associated mortality rate was lower in Italy than in other countries, and cases reported in the country typically had a milder course than did those reported elsewhere. Nevertheless, 9 of our cases (33%) rapidly evolved to respiratory failure, requiring mechanical ventilation.

Keywords: Pneumonia; Influenza A virus, H1N1 subtype; Respiratory insufficiency.

The objective of this study was to review the literature related to avian influenza A (H5N1). The bibliographic research was conducted using the Medline, MD Consult, HighWire, Medscape and Literatura Latinoamericana y del Caribe en Ciencias de la Salud (LILACS, Latin American and Caribbean Health Sciences Literature) databases, as well as through direct research, limiting the scope to articles published within the past 10 years. We selected 31 original articles addressing the recent outbreaks of infection with the H5N1 subtype of avian influenza A in domesticated birds in Asia, which have resulted in significant economic losses and repercussions for public health, as well as some cases of human infection presenting high lethality. In most cases, infection has been associated with direct exposure to infected birds or contact with surfaces infected with bird excrement. However, cases of human-to-human transmission have been confirmed. In those cases, the incubation period varied from 2 to 4 days. The clinical manifestations range from asymptomatic infection to mild upper airway disease, pneumonia and multiple organ failure. Chest X-rays may reveal bilateral interstitial infiltrate, lobar collapse, focal consolidation and air bronchogram without pleural effusion. Lymphopenia is indicative of a poor prognosis. Supportive care appears to be the only acceptable treatment. Risk factors for poor prognosis include advanced age, delayed hospitalization, lower airway involvement, low white blood cell count or lymphopenia upon admission. Controlling outbreaks in domestic fowl and limiting contact between humans and infected birds must be the priorities in the management of this disease at the public health level. In addition, techniques and knowledge regarding the disease should be widely disseminated.

Keywords: Influenza A virus, avian /pathogenicity; Influenza; Disease outbreaks; Disease vectors; Clinical trials

This study aimed to review the literature on infection with the H5N1 subtype of avian influenza A virus, taking into consideration the fact that, in the event of a pandemic, children might become a major risk group. Searches were limited to the past ten years and were carried out using the following electronic databases: Medline, MD Consult, HighWire and Medscape. Children and young adults account for a significant proportion of the susceptible population. We found that more than half of the individuals infected were under 20 years of age and that one quarter were under the age of 10. The incubation period ranged from 2 to 5 days. Initial clinical manifestations are nonspecific, which hinders the diagnosis. Most of the infected individuals presented severe pneumonia, which evolved to respiratory insufficiency within an average of 4 days. Chest X-rays can reveal diffuse multifocal/interstitial infiltrates or segmental/lobar consolidation with air bronchogram. The pathogenic potential is high, with mortality rates up to 63%, indicating that the pandemic virus might present high pathogenicity and high mortality. Knowledge of the risk of a pandemic and of the measures to be taken in suspect cases constitutes an important step toward controlling a potential pandemic.

Keywords: Influenza A virus; Disease vectors; Disease outbreaks; Influenza A virus, H5N1 subtype.

Hepatopulmonary syndrome is characterized by a triad consisting of liver disorder, pulmonary vascular dilatation, and hypoxemia. No case of hepatopulmonary syndrome associated with AIDS has been reported so far. In this study, the authors report the case of a 43-year woman with AIDS and virus C cirrhosis taking prophylactic cotrimoxazole for pneumocystosis and retroviral therapy. Upon admission, the patient presented dyspnea, cyanosis, digital clubbing, vascular spiders, and normal chest examination. Chest X-ray revealed bilateral interstitial infiltration and evidenced increased alveolar-arterial gradient and liver function impairment. Intrapulmonary shunt was evidenced by contrast-enhanced echocardiography and radionuclide perfusion scanning, thus confirming hepatopulmonary syndrome.

Keywords: Hepatopulmonary syndrome. Acquired human immunodeficiency syndrome. Human viral hepatitis. Anoxemia. Liver cirrhosis.

Objective: In view of the relevance of co-infection with tuberculosis and human immunodeficiency virus, this study was designed to determine tuberculosis prevalence and identify factors related to tuberculosis in patients residing in a region in which both infections are highly prevalent. Methods: All patients treated during 1999 at the HIV/AIDS Clinic of the Universidade Federal do Rio Grande (Rio Grande Federal University) University Hospital were evaluated retrospectively, from the time of human immunodeficiency virus diagnosis, in terms of the incidence of tuberculosis and its relationship to sociodemographic, behavioral and immunological factors. Results: The sample included 204 patients, and tuberculosis prevalence was found to be 27%. The multivariate analysis showed a significant correlation between the development of tuberculosis and being of African descent (odds ratio: 4.76; 95% confidence interval: 1.93-11.72) and an inverse correlation between the development of tuberculosis and the TCD4+ lymphocyte count at the time of human immunodeficiency virus diagnosis (odds ratio: 0.995; 95% confidence interval: 0.993-0.997). When analyzed separately, other variables were found to be potential risk factors: being of the male gender (odds ratio: 2.49; 95% confidence interval: 1.15-5.39); and using illicit drugs (odds ratio: 2.1; 95% confidence interval: 1.02-4.31). Conclusion: The factors responsible for the development of tuberculosis among patients who are human immunodeficiency virus seropositive include immunological, socioeconomic and demographic factors. The high rate of tuberculosis prevalence among the seropositive patients underscores the urgent need to implement strategies that combine rapid identification and prompt treatment of individuals with active or latent infection, as well as of those with whom they have been in contact.

Keywords: HIV Infections/complications; AIDS-related opportunistic infections/complications; Tuberculosis/etiology; Tuberculosis/epidemiology

A total of 287 bronchoscopies were performed in 267 patients infected with the human immunodeficiency virus (HIV). Bronchoalveolar lavage (BAL) and transbronchial biopsies (TBB) were sequentially performed in the same lung, in all cases. Specimens were examined after routine laboratory procedures for microbiologic and histologic analysis. Age ranged from 16 to 78 (median 37.2); 228 were men (85.4%) and 39 were women. Dyspnea was the main symptom in 198 cases (69.0%) and interstitial infiltrates (diffuse or localized) were the most common findings at chest radiographs (179 patients, 62.4%). Endoscopic view was normal in 246 patients (85.7%). Mucosal lesions suggestive of Kaposi's sarcoma (KS) were visible in 12 cases (4.2%). BAL detected 97 infectious agents, simultaneous co-infection occurred in 3 cases. TBB identified 165 pathogens (9 of them in association), anticipating a better yield than BAL in the diagnosis of P. carinii (84 versus 51, respectively) and cytomegalovirus (35 v. 0). Biopsies were unique in establishing the appropriate diagnosis of extrabronchial cancer and describing inespecific pneumonitis. Altogether, a definite diagnosis was obtained by bronchoscopic examination (including endoscopic view, BAL and TBB) in 271 of 287 cases (94.4%). Infections were caused by P. carinii in 105 patients (36.6%), Mycobacterium sp in 40 (13.9%), cytomegalovirus in 35 (12.2%), C. neoformans in 13 (4.5%) etc. Malignancies (including KS) were found in 16 patients (5.6%). More than one pathologic process was present in 28 (9.8%). Nonspecific pneumonitis was diagnosed in 56 cases (19.5%) and normal lung in 20 (7.0%). Complications related to bronchoscopy were pneumothorax (8 patients, 2.8%), haemorrhage (8), thoracic pain (2) and distal pneumonia (2). Chest tubes were required in 4 patients, including one fatal case (mortality rate of 0.3%). Combining BAL and TBB results increases the diagnostic yield of bronchoscopy in AIDS, with a low complication rate. If both techniques are performed, a higher number of infectious agents and more multiple causes of pulmonary disease may be identified.

Keywords: Bronchoscopy/methods. Acquired Immunodeficiency Syndrome/complications. Opportunistic infections related to AIDS/diagnosis.

Objective: To evaluate tuberculin test results and relate them to the presence or absence of active tuberculosis, as well as to CD4+ and CD8+ T-lymphocyte counts. Method: The charts of 802 patients with acquired immunodeficiency syndrome treated between August of 1985 and March of 2003 were reviewed. Of the 185 patients submitted to tuberculin tests (23.1%), 107 (57.8%) were male, and 78 (42.2%) were female. Patients were divided into two study groups: tuberculin test reactors (n = 28); and tuberculin test non-reactors (n = 157). Among the reactors, the mean age was 30.60 years, with a standard deviation of 6.62 years, compared with 34.45 years, with a standard deviation of 10.32 years, among the non-reactors. Results: Most of the individuals tested presented only a mild response to the tuberculin test. We found that, at the time of the test, the percentage of individuals with active tuberculosis was greater in the reactor group than in the non-reactor group. During the test period, 10 reactor group patients and 11 non-reactor group patients presented some clinical form of active tuberculosis. In addition, CD4+ T-lymphocyte counts were lower than 200 cells/mm3 in 6 reactor group patients and in 8 non-reactor group patients. Conclusion: Indurations greater than 5 mm were unrelated to higher absolute CD4+ T-cell counts.

Keywords: Tuberculin test; Acquired immunodeficiency syndrome; Tuberculosis; CD4-positive T-lymphocytes; CD8-positive T-lymphocytes

Objective: To estimate the prevalence of human immunodeficiency virus seropositivity among patients with active tuberculosis residing in the city of Londrina, in the state of Paraná, Brazil and treated at the Pulmonology Clinic of the 17th Regional Health Facility of the State of Paraná, and to compare those coinfected with human immunodeficiency virus to those with active tuberculosis only in terms of the clinical form of tuberculosis, sputum smear microscopy, chest X-ray and tuberculosis treatment regimen. Methods: A transversal study involving 188 active tuberculosis patients was conducted. Tuberculosis and human immunodeficiency virus infection were diagnosed based on criteria established by the Brazilian Ministry of Health. In addition to the data obtained through individual tuberculosis investigation files, clinical and epidemiological information were collected by means of questionnaires, which were completed by all participating patients. Results: The prevalence of human immunodeficiency virus seropositivity among patients with tuberculosis was 14.9%. The rate of positive sputum microscopy results was higher in the tuberculosis-only group (p = 0.0275), and the ratio for patients treatment with alternative scheme was significantly higher in the co-infected group (p = 0.042). In 32.1% of the coinfected patients, the serological diagnosis of human immunodeficiency virus infection was made simultaneously to or following that of the tuberculosis. Conclusion: The results underscore the importance of routinely testing for human immunodeficiency virus antibodies in patients diagnosed with tuberculosis.

Keywords: Tuberculosis/complications; Tuberculosis/diagnosis; Soropositivity; HIV/immunology; HIV infections/complications; HIV infections/epidemiology; HIV infections/ drug therapy; Rifampin/therapeutic use; Disease progression

Objective: To discuss the main aspects of co-infection with Mycobacterium tuberculosis and human immunodeficiency virus in the city of Taubaté (located in the state of São Paulo, Brazil) in 2001 and 2002. Methods: This study presents epidemiological data on tuberculosis cases occurring in Taubaté in 2001 and 2002. Results: Of the 250 cases of tuberculosis analyzed, 70 (28%) presented human immunodeficiency virus seropositivity, 95 (38%) presented human immunodeficiency virus seronegativity, and 85 (34%) were patients who had not been submitted to serological testing. In the first group (tuberculosis and human immunodeficiency virus seropositivity), males from 30 to 40 years of age predominated, the most common clinical presentation of tuberculosis was pulmonary (65.71%), and the cure rate was 59.38%. In the group of tuberculosis patients presenting human immunodeficiency virus seronegativity, males from 30 to 40 years of age also predominated, the most common clinical presentation of tuberculosis was also pulmonary (70.55%), and the cure rate was 81.63%. Conclusion: We conclude that the human immunodeficiency virus plays an important role in the epidemiology of tuberculosis. Therefore, serological testing for human immunodeficiency virus should be carried out when a diagnosis of tuberculosis is made.

Keywords: Tuberculosis/epidemiology; HIV infections; HIV; Prevalence

Objective: In order to study the scenario of respiratory infections in pediatrics after the emergence of SARS-CoV-2 in Brazil, this study aimed to compare characteristics of children admitted for SARS or upper airway infection caused by either RSV or SARS-CoV-2. Methods: This was a cross-sectional study involving children up to 48 months of age admitted to a tertiary pediatric hospital with a diagnosis of SARS or upper airway infection between April of 2020 and April of 2021. Respiratory secretion samples were collected 2-5 days after hospitalization, and antigen/PCR tests for viral etiologies were performed. In this analysis, patients with laboratorial diagnosis of SARS-CoV-2 and/or RSV were selected, and their clinical and epidemiological characteristics were compared using logistic regression. Results: Our sample initially comprised 369 participants. SARS-CoV-2 and RSV infections were confirmed in 55 (15%) and 59 children (16%), respectively. Mean age was 12 months (0-48 months), and 47 were female. The following characteristics were significantly more frequent in patients with RSV when compared with those with COVID-19: younger age (OR = 0.94; 95% CI: 0.90-0.98); lower frequency of fever (OR = 0.18; 95% CI: 0.05-0.66); and more frequent upper airway symptoms: cough (OR = 7.36; 95% CI: 1.04-52.25); and tachypnea (OR = 6.06; 95% CI: 1.31-28.0). Conclusions: Children with RSV-related SARS were younger, had lower frequency of fever at admission, but had a higher frequency of signs of upper airway infection and lower systemic inflammation when compared with children hospitalized for COVID-19 during the first year of the pandemic.

Keywords: SARS-CoV-2; Respiratory syncytial virus infections; Pediatrics; Brazil.

Objective: To compare mortality rates due to respiratory diseases among elderly individuals residing in the Federal District of BrasÝlia, Brazil, prior to and after the implementation of a national influenza vaccination campaign. Methods: This was an ecological time series analysis. Data regarding the population of individuals who were over 60 years of age between 1996 and 2009 were obtained from official databases. The variables of interest were the crude mortality rate (CMR), the mortality rate due to the respiratory disease (MRRD), and the proportional mortality ratio (PMR) for respiratory diseases. We performed a qualitative analysis of the data for the period prior to and after the implementation of the vaccination campaign (1996-1999 and 2000-2009, respectively). Results: The CMR increased with advancing age. Over the course of the study period, we observed reductions in the CMR in all of the age brackets studied, particularly among those aged 80 years or older. Reductions in the MRRD were also found in all of the age groups, especially in those aged 80 years or older. In addition, there was a decrease in the PMR for respiratory diseases in all age groups throughout the study period. The most pronounced decrease in the PMR for respiratory diseases in the ≥ 70 year age bracket occurred in 2000 (immediately following the implementation of the national vaccination campaign); in 2001, that rate increased in all age groups, despite the greater adherence to the vaccination campaign in comparison with that recorded for 2000. Conclusions: Influenza vaccination appears to have a positive impact on the prevention of mortality due to respiratory diseases, particularly in the population aged 70 or over.