High human bocavirus viral load is associated with disease severity in children under five years of age

Area of Science:

• Virology
• Pediatric Infectious Diseases
• Respiratory Medicine

Background:

• Human bocavirus (HBoV) is a parvovirus implicated in lower respiratory tract infections (LRTIs).
• Its pathogenic role in respiratory illness is debated due to frequent co-infections with other respiratory viruses.
• Understanding HBoV prevalence and its contribution to disease severity is crucial for pediatric respiratory health.

Purpose of the Study:

• To investigate the prevalence of HBoV infection in children under five with LRTIs in Shanghai.
• To determine the correlation between HBoV infection and disease severity.
• To analyze HBoV viral loads and co-infection patterns.

Main Methods:

• A 3-year prospective study involving healthy controls, outpatients, and inpatients diagnosed with LRTIs.
• Real-time PCR was used to detect HBoV subtypes 1-4 and other common respiratory viruses in nasopharyngeal aspirates and swabs.
• Quantitative real-time PCR determined viral loads in all HBoV-positive samples.

Main Results:

• HBoV1 was detected in 7.0% of inpatients, with varying annual rates from 2010-2012.
• Respiratory syncytial virus (RSV) subtype A was the most common co-infection; HBoV1 and RSVA showed similar seasonal patterns.
• High HBoV viral loads (>10^6 copies/ml) were significantly more prevalent in patients with LRTIs than in healthy controls.
• A direct correlation was observed between high viral load and increased disease severity in co-infected patients.

Conclusions:

• HBoV1 is a significant cause of LRTIs in young children.
• Symptomatic HBoV infection is associated with high viral loads, particularly in cases of co-infection.
• These findings highlight the importance of viral load assessment in determining HBoV's pathogenic role in respiratory infections.