Respiratory viruses in pediatric necropsies: an immunohistochemical study.

Infections of the respiratory system are responsible for the majority of hospitalizations and deaths in pediatric patients in developing countries. We selected 177 necropsies of pediatric patients who died as a result of serious respiratory infections. The histopathological findings and epidemiological data were reviewed, and lung tissue samples were separated for immunohistochemistry testing. Conventional immunohistochemistry techniques were used to detect viral antigens in formalin-fixed, paraffin-embedded (FF-PE) lung tissue samples using a pool of monoclonal antibodies against respiratory viruses (respiratory syncytial virus, influenza A and B, adenovirus, and parainfluenza 1, 2, and 3 viruses) as primary antibodies. The histopathological findings were classified into bronchopneumonia (BCP) and interstitial pneumonitis (IP) patterns. The immunohistochemistry results were compared with histopathological patterns and epidemiological data. Positive results for viruses were found in 34% and 62.5% of the BCP and IP cases, respectively. Males and infants below 1 year of age were more frequent in the group that had positive results for viruses. Acute enteritis was the main cause of hospitalization and sepsis the most frequent cause of death in this group. A clear seasonal distribution was observed, with the majority of cases occurring in the 2nd and 3rd trimesters (autumn and winter) of each year in the period studied. Immunohistochemistry is an affordable and easy-to-perform method for viral-antigen detection in FF-PE tissue samples. Although BCP is a classic histopathological pattern found in bacterial infections, it is possible that children with serious respiratory infections had concomitant viral and bacterial infections, regardless of their previous immunologic state.

Respiratory tract viral infections in bone marrow transplant patients.

BACKGROUND: Community respiratory viruses such as respiratory syncytial virus (RSV), adenovirus, influenza A, influenza B, and the parainfluenza group are frequent causes of respiratory disease in bone marrow transplant (BMT) patients. MATERIAL AND METHODS: During the period from March 1993 to August 1999, 810 samples of respiratory secretions, nasopharyngeal aspirate (NPA) or bronchoalveolar lavage (BAL), from 722 patients with upper respiratory infections symptoms at the BMT unit of the Federal University in the state of Paraná, Brazil were evaluated for respiratory virus infection. RESULTS: One hundred thirty-six (17%) samples were reactive in 62 patients. RSV was found in 30 of 62 (48%), influenza A in 14 of 62 (23%), influenza B in 9 of 62 (15%), parainfluenza group in 7 of 62 (11%), and adenovirus in 2 of 62 (3%) infected patients. The most frequent clinical manifestations were cough and fever. Pneumonia occurred in 19 of 62 (31%) cases. The mortality rate was 23 of 62 (37%), being higher among patients infected with adenovirus and influenza A. CONCLUSIONS: Infections in BMT patients occurred during the outbreak period of these viruses in the community, highlighting the need to establish surveillance measures in units with immunocompromised patients in addition to the development of sensitive and rapid diagnostic tests for the detection of these viruses in patients with respiratory symptoms.

Comparison of latex agglutination with enzyme immunoassay for detection of rotavirus in fecal specimens.

Human rotaviruses are the most important etiologic agents of acquired diarrhea in infants and young children worldwide. Early diagnosis is essentialfor effective patient treatment. The latex agglutination (LA) assays for rotavirus diagnosis are rapid, inexpensive, and the most widely used to screen specimens. The performance of the LA Rotagen (Biokit S.A., Barcelona, Spain) was evaluated for rotavirus detection infecal samples of outpatients with acute gastroenteritis. This assay was compared with the enzyme immunoassay (EIA) EIARA (Bio-Manguinhos, Rio de Janeiro, Brazil). From January to October 2000, 285 fecal specimens were analyzed. Forty-four samples (15.4%) were reactive, 214 (75.4%) were nonreactive, and 27 (9.5%) were indeterminate by LA. All LA-positive samples were positive by EIA, and 2 LA-negative samples were positive by EIA. Of specimens indeterminate by LA, 67% were positive by EIA. The sensitivity, specificity, and accuracy of LA were 69%, 100%, and 93%, respectively. These results indicate that assay is as sensitive and specific as the EIA, and it could be applied on a large scale for screening stool specimens in suspected rotavirus diarrhea. However, the indeterminate results must be confirmed by other methods, such as EIA.