Human bocavirus-1 infections in Australian children aged < 2 years: a birth cohort study

Abstract

To determine human bocavirus-1 (HBoV1) infection characteristics in young Australian children. Data were from the Observational Research in Childhood Infectious Diseases (ORChID) study, a Brisbane, Australia–based birth cohort of healthy, term, newborns followed prospectively for 2 years. Parents recorded daily symptoms, maintained an illness-burden diary, and collected weekly nasal swabs, which were tested for 17 respiratory viruses, including HBoV1, by real-time polymerase chain reaction (PCR) assays. Main outcomes measured were infection incidence, risk factors, symptoms, and healthcare use. One hundred fifty-eight children in the ORChID cohort provided 11,126 weekly swabs, of which 157 swabs were HBoV1 positive involving 107 incident episodes. Co-detections were observed in 65/157 (41.4%) HBoV1-positive swabs (or 41/107 [38.3%] infection episodes), principally with rhinovirus. Shedding duration was 1 week in 64.5% of episodes. The incidence of HBoV1 infections in the first 2 years of life was 0.58 episodes per child-year (95% confidence interval [CI] 0.47–0.71), including 0.38 episodes per child-year (95% CI 0.30–0.49) associated with respiratory symptoms. Recurrent episodes occurred in 18/87 (20.7%) children following their primary infection. In the first 2 years of life, incidence of HBoV1 episodes increased with age, during winter and with childcare attendance. Overall, 64.2% of HBoV1 episodes were symptomatic, with 26.4% having healthcare contact. Viral load estimates were higher when children were symptomatic than when asymptomatic (mean difference = 3.4; 95% CI 1.0–5.7 PCR cycle threshold units). After age 6 months, HBoV1 is detected frequently in the first 2 years of life, especially during winter. Symptoms are usually mild and associated with higher viral loads. Supplementary Information The online version contains supplementary material available at 10.1007/s10096-022-04529-x.

A Review on Human Metapneumovirus and Human Bocavirus Associated with Acute Respiratory Tract Infections

“…The EIA of IgG avidity has been developed to identify primary HBoV infection and immune activation [89]. ELISA techniques can find HBoV antibodies in serum using VLPs of VP1 and VP2 viruses [90,91]. Detecting HBoV infections can be made possible by immunofluorescence assays that look for IgG antibodies and biomarker-based assays [92][93][94].…”

Human bocavirus respiratory infection: Tracing the path from viral replication and virus‐cell interactions to diagnostic methods

“…But approximately 40% cases of primary infection have <1 � 10 4 gc/mL during the initial phase of the symptomatic period and it has been observed that in some patients there is not correlation between high viral load in respiratory secretions (>10 6 gc/mL) and active infection (mRNA negative). 43,44,52,54,68,117,118 Detection of HBoV1 RNA in paediatric patients, rather than high viral load, has been associated with wheezing and pneumonia, thus it could be useful to identify active infection. 117,[119][120][121][122] An alternative for diagnosis in clinical practice could also be direct testing by antigen detection (immunofluorescence), 88 along with the respiratory panel.…”

“…Some authors suggest that 1 × 10 4 –1 × 10 8 genome copies (gc) per mL of respiratory secretion indicate acute stage of infection. But approximately 40% cases of primary infection have <1 × 10 4 gc/mL during the initial phase of the symptomatic period and it has been observed that in some patients there is not correlation between high viral load in respiratory secretions (>10 6 gc/mL) and active infection (mRNA negative) 43,44,52,54,68,117,118 …”

Human Bocavirus in Childhood: A True Respiratory Pathogen or a “Passenger” Virus? A Comprehensive Review

“…Most literature reported HBoV infection as prevalent in children between 6 months and 2 years with the highest detection rate during the second year [ 4 , 6 , 10 , 12 , 13 , 14 ], while it is rare (<5%) during the first 6 months of life [ 15 , 16 ]. Only in the study by Wang et al were children > 5 years the most affected, followed by children < 2 years and infants [ 1 , 15 , 16 ].…”

“…Although HBoV 2–4 variants have also been found in respiratory tract samples at lower frequencies, their role in the pathogenesis of respiratory infections is unclear. Moreover, HBoVs have been detected in urine [ 8 ], saliva [ 9 ], blood [ 10 , 11 ], tonsils [ 12 , 13 ], cerebrospinal fluid [ 14 ], and in environmental samples such as river water [ 15 ], sewage [ 16 , 17 ], and shellfish [ 18 ] with uncertain clinical significance.…”