Human Bocavirus in Brazil: Molecular Epidemiology, Viral Load and Co-Infections

Area of Science:

• Virology
• Pediatric Infectious Diseases
• Public Health Microbiology

Background:

• Human bocavirus (HBoV) is an emerging pathogen increasingly detected globally, particularly in children with respiratory and gastrointestinal symptoms.
• Understanding HBoV prevalence, genetic diversity, and shedding patterns is crucial for managing pediatric infections.

Purpose of the Study:

• To determine the prevalence, genotypes, and DNA shedding of HBoV in stool samples from young children in Brazil.
• To investigate co-infections with other enteric viruses and analyze HBoV viral load in different infection scenarios.

Main Methods:

• Analysis of 886 acute gastroenteritis stool samples from Brazilian children (2016-2017) using TaqMan-based qPCR for HBoV detection and quantification.
• Genotyping of positive samples via VP1/2 overlap region sequencing, followed by phylogenetic analysis.
• Screening for co-infections with other common gastroenteric viruses.

Main Results:

• HBoV was detected in 12.4% (110/886) of samples, with viral loads ranging from 1.6 x 10^2 to 1.2 x 10^9 genome copies/gram.
• Co-infections were prevalent (79.1%), and HBoV showed significantly lower viral loads compared to rotavirus, norovirus, and adenovirus in dual infections (p < 0.05).
• HBoV-1 (38%), HBoV-2 (40%), and HBoV-3 (22%) were the circulating genotypes, with no significant differences in HBoV viral load based on genotype or age.

Conclusions:

• HBoV is a common finding in Brazilian children with acute gastroenteritis, with multiple genotypes circulating.
• The high rate of co-infections suggests complex interactions, and HBoV may play a role in gastroenteritis, especially when other common viruses are absent.
• Continuous HBoV monitoring is essential to fully elucidate its clinical significance in diarrheal diseases.