Frequent Detection and Genetic Diversity of Human Bocavirus in Urban Sewage Samples

Abstract

The prevalence and genetic diversity of human bocaviruses (HBoVs) in sewage water samples are largely unknown. In this study, 134 raw sewage samples from 25 wastewater treatment plants (WTPs) in Italy were analyzed by nested PCR and sequencing using species-specific primer pairs and broad-range primer pairs targeting the capsid proteins VP1/VP2. A large number of samples (106, 79.1 %) were positive for HBoV. Out of these, 49 were classified as HBoV species 2, and 27 as species 3. For the remaining 30 samples, sequencing results showed mixed electropherograms. By cloning PCR amplicons and sequencing, we confirmed the copresence of species 2 and 3 in 29 samples and species 2 and 4 in only one sample. A real-time PCR assay was also performed, using a newly designed TaqMan assay, for quantification of HBoVs in sewage water samples. Viral load quantification ranged from 5.51E+03 to 1.84E+05 GC/L (mean value 4.70E+04 GC/L) for bocavirus 2 and from 1.89E+03 to 1.02E+05 GC/L (mean value 2.27E+04 GC/L) for bocavirus 3. The wide distribution of HBoV in sewages suggests that this virus is common in the population, and the most prevalent are the species 2 and 3. HBoV-4 was also found, representing the first detection of this species in Italy. Although there is no indication of waterborne transmission for HBoV, the significant presence in sewage waters suggests that HBoV may spread to other water environments, and therefore, a potential role of water in the HBoV transmission should not be neglected.

The impact of anthropogenic pressure on the virological quality of water from the Tiber River, Italy

“…Both species 2 and 3 of HBoV were detected, confirming results obtained in urban wastewaters (Iaconelli et al . ).…”

“…In Italy, a recent study revealed a significant presence HBoV (subtypes 2, 3, and 4) in 79% of wastewater samples (Iaconelli et al . ), suggesting that this virus can contaminate surface waters that are impacted by effluent discharges. Interestingly, HBoV was the most frequently detected virus in our river water samples, exceeding even AdV, a pathogen previously proposed as an indicator for the monitoring of human faecal contamination of surface waters (Bofill‐Mas et al .…”

“…We therefore used, in parallel with the hollow fibre ultrafiltration, an adsorption/elution method, one of the most commonly employed methods for the concentration of viruses from water samples, which we had previously used successfully to concentrate river waters (Iaconelli et al . , ). We found that the adsorption/elution method gave a higher number of positive samples, compared with ultrafiltration method.…”

“…Human Bocavirus (HBoV) was also investigated, in light of its recent detection in the vast majority of urban wastewater samples in Italy (Iaconelli et al . ), suggesting that the virus could spread to surface waters affected by discharge effluents.…”

Regional, age and respiratory-secretion-specific prevalence of respiratory viruses associated with asthma exacerbation: a literature review

“…For RSV, apart from the greater likelihood of initial infection of the nasopharyngeal mucosa, followed by spreading of the virus to the lower airways [20], the extensive use of nasal swabs, but not spontaneous or induced sputum for sample collection from children might also have resulted in a higher apparent prevalence in upper airway secretions. Furthermore, the higher prevalence of BoV and EnV detected in upper airway secretions might be associated with fecalto-oral transmission [21] or transmission from oral mucosa or salivary glands [22], which would be detected more frequently in infants and toddlers.…”