Clinical and epidemiologic profile of lower respiratory tract infections associated with human bocavirus

Acute viral bronchiolitis (AVB) remains the leading cause of lower respiratory tract infection (LRTI) in infants under 2 years of age. Advances in molecular methods for virus detection have led to the identification of new infectious agents implicated in the development of AVB, such as human bocavirus (HBoV).

To ascertain the frequency, seasonality, and clinical behavior of HBoV detection in a series of episodes of LRTI.

The frequency of HBoV was assessed in children with LRTI episodes, aged 1-24 months, seen at the emergency department of Hospital da Criança Santo Antônio, Porto Alegre, Brazil, between May 2007 and July 2008. Virus-specific polymerase chain reaction was used for detection.

A total of 455 nasal secretion samples were collected from 433 patients over a 14-month period. Of these, 60 were positive for HBoV (13.2%). Mean age was 7.9 months and 55% of patients were male. Just over half of patients were under 6 months of age (53.3%). Wheezing was the presenting respiratory complaint in 51.7%. Of the 60 patients, 80% were admitted to a pediatric ward. Diarrhea was present in nine patients (18%). Co-detection was a frequent finding in our sample, occurring in 95% of cases. In our series, the distribution of HBoV was clearly seasonal and was influenced by temperature, relative humidity, and precipitation.

We conclude that HBoV detection in infants with AVB and recurrent wheezing of viral etiology in Brazil is similar to that reported in other countries. The clinical course of HBoV detection is no different from that of other respiratory viruses commonly found in this age range.