Bronchiolitis in tropical south India
T. Cherian, E. A. Simoes, M. C. Steinhoff, K. Chitra, M. John, P. Raghupathy and T. J. John
Department of Virology, Christian Medical College and Hospital, Vellore, Tamilnadu, India.
In a prospective hospital-based study of 328 children under 5 years of age
with acute lower respiratory infections, 114 (35%) were diagnosed to have
acute bronchiolitis. Of them, 87 (76%) were less than 1 year and 107 (94%)
were less than 2 years of age. Signs of severe lower respiratory
infections, namely tachypnea (respiratory rate greater than 50/min) and
subcostal retraction, were present in 95% and 93%, respectively. Of 88
children of whom roentgenographs were taken, 30 (34%) had evidence of
pneumonia. No clinical signs discriminated between those with and without
pneumonia. By culture or immunofluorescence antigen detection, viruses were
found in 81 (71%) children with bronchiolitis; respiratory syncytial virus
was the most common agent, found in 65 (57%). Parainfluenza viruses were
the next most common, found in 12 (11%). Most cases of bronchiolitis
occurred in outbreaks during the rainy months of August through November,
coinciding with respiratory syncytial virus outbreaks. Although bacterial
culture of blood was done in 56 children, no respiratory pathogen was
isolated. In one child with bronchiolitis and consolidation, postmortem
lung aspirate yielded Staphylococcus aureus. Thus, bronchiolitis is
primarily a viral syndrome in this tropical region, just as it is in
temperate regions. Eight (7%) children died (all were infants); 5 had
roentgenographic pneumonia and the remaining had other abnormalities
contributing to death; all had been treated with antibiotics. Since one
third of lower respiratory infections are bronchiolitis, and among infants
under 1 year of age bronchiolitis comprises 47% of all lower respiratory
infection cases, criteria for antibiotic management must take into account
the availability of roentgenographic investigation.
