Atypical presentation of human bocavirus: Severe respiratory tract infection complicated with encephalopathy

Human bocavirus (HBOV) has been reported as a worldwide distributed respiratory pathogen. It has also been associated with encephalitis recently by detection of the virus in cerebrospinal fluid (CSF) of patients presented with encephalitis. This retrospective study aimed to present clinical features of HBOV infections in children with respiratory symptoms and describe unexplained encephalopathy in a subgroup of these patients. Results of 1,143 pediatric nasal samples from mid-December 2013 to July 2014 were reviewed for detection of HBOV. A multiplex real time polymerase chain reaction assay was used for viral detection. Medical records of the patients were retrospectively analyzed. HBOV was detected in 30 patients (2.6%). Median age was 14 months (5-80). Clinical diagnoses were upper respiratory tract infection (n = 10), bronchopneumonia (n = 9), acute bronchiolitis (n = 5), pneumonia (n = 4), acute bronchitis (n = 1), and asthma execarbation (n = 1). Hospitalization was required in 16 (53.3%) patients and 10 (62.5%) of them admitted to pediatric intensive care unit (PICU). Noninvasive mechanical ventilation modalities was applied to four patients and mechanical ventilation to four patients. Intractable seizures developed in four patients while mechanically ventilated on the 2nd-3rd days of PICU admission. No specific reason for encephalopathy was found after a thorough investigation. No mortality was observed, but two patients were discharged with neurological sequela. HBOV may lead to respiratory infections in a wide spectrum of severity. This report indicates its potential to cause severe respiratory infections requiring PICU admission and highlights possible clinical association of HBOV and encephalopathy, which developed during severe respiratory infection.