Acute viral bronchiolitis in South Africa: Viral aetiology and clinical epidemiology

Bronchiolitis is a viral-induced lower respiratory tract infection that occurs predominantly in children <2 years of age, particularly infants. Many viruses have been proven or attributed to cause bronchiolitis, including and most commonly the respiratory syncytial virus (RSV) and rhinovirus. RSV is responsible for more severe disease and complications (including hospitalisation) in bronchiolitis patients. Whereas bronchiolitis is exclusively due to respiratory viral infections, with little evidence of bacterial co-infection, the former could nevertheless predispose to superimposed bacterial infections. Although data support an interaction between RSV and pneumococcal superimposed infections, it should be noted that this specifically refers to children who are hospitalised with RSV-associated pneumonia, and not to children with bronchiolitis or milder outpatient RSV-associated illness. As such, empiric antibiotic treatment against pneumococcus in children with RSV-associated pneumonia is only warranted in cases of hospitalisation and when the clinical syndrome is more in keeping with pneumonia than uncomplicated bronchiolitis. In South Africa, the peak in the RSV season varies only slightly by province, with onset in February, and lasting until June. The important implication of these new seasonality findings is that where prophylaxis is possible, as in the case of RSV, it should be commenced in January of each year.