Human bocavirus infection in children with gastroenteritis, Brazil

Prevalence, Molecular Epidemiology, and Clinical Characteristics of Human Bocavirus Among Patients with Acute Gastroenteritis in Northern Brazil During 2017-2022

Acute gastroenteritis (AG) is a major illness in early childhood. Recent studies suggest a potential association between human bocavirus (HBoV) and AG. HBoV, a non-enveloped virus with a single-strand DNA genome, belongs to the Parvoviridae family. This study aimed to describe the frequency of HBoV in Northern Brazil using samples from patients with AG collected between 2017 and 2022. Fecal samples obtained from the viral gastroenteritis surveillance network at the Evandro Chagas Institute (IEC) were analyzed. Fecal suspensions (20%) were prepared, and the viral genome was extracted. PCR and nested-PCR were employed to detect HBoV, followed by nucleotide sequencing to identify viral types. Out of 692 samples, HBoV positivity was detected in 9.2% of cases (64/692). Genotypes HBoV-1, HBoV-2, HBoV-3, and HBoV-4 were found in 42.5% (17/40), 22.5% (9/40), 32.5% (13/40), and 2.5% (1/40) of the specimens, respectively. Co-infections with HBoV and other enteric viruses occurred in 48.3% (31/64) of cases, with RVA being the most frequent (31.2%, 20/64). The study results underscore the importance of continuous monitoring and further research to better understand the seasonality, coinfection patterns, and genetic variability of HBoV.

Human Bocavirus Circulating in Patients with Acute Gastroenteritis in Taiwan, 2018-2022

Human bocavirus (HBoV) has been identified as a viral agent with a global presence, especially in young patients with gastrointestinal infections. In this study, we aimed to evaluate the epidemiological patterns of the HBoVs associated with acute gastroenteritis (AGE) in Taiwan. A total of 2994 AGE fecal samples from several diarrhea outbreaks from 2018 to 2022 were analyzed. From the samples, 73 positive samples were detected in three different bocaviruses: 30 (41.1%) were from HBoV1; 37 (50.7%) were from HBoV2; and 6 (8.2%) were from HBoV3, revealing the respective prevalences in AGE of 1%, 1.2%, and 0.2%. HBoV1 and HBoV2 were the two major epidemic agents of HBoVs in Taiwan during this study period and have seasonal distinct patterns with an epidemic peak from October to the following March. Phylogeny reconstruction and evaluation were implemented in Mega X; the results revealed that most HBoV1 strains in Taiwan appeared to be closely related to those strains from other Asian countries. The HBoV2 exhibited substantial genetic diversity and the HBoV3 genes showed discordance of groups.

Bocaparvovirus in infants hospitalized in a neonatal intensive care unit in Midwest Brazil during the COVID-19 pandemic (2021-2022)

Human bocaparvoviruses (HBoVs) belong to the Parvoviridae family, being currently classified into four species (HBoV1-4). These viruses have been found in association with respiratory and gastroenteric symptoms, as well as in asymptomatic individuals. This study aimed to investigate the occurrence of HBoVs in infants under 5 months old admitted to a Neonatal Intensive Care Unit (NICU) during the COVID-19 pandemic (between March 2021 and March 2022). Clinical samples (nasopharyngeal swab, serum, stool, and urine) were screened by qPCR TaqMan. The HBoV was detected in samples of 31.6% (12/38) of participants. The most frequent alteration among the HBoV-positive neonates was the chest X-ray with interstitial infiltrate, followed by tachycardia and vomiting. Viral DNA was detected in more than one type of clinical sample in three of the participants in association with respiratory symptoms. Two participants had positive stool samples with or without enteric symptoms. HBoV intermittent and continuous positivity patterns were observed. The present study stands out for the prospective evaluation of positivity for HBoV in different types of clinical samples from a population of hospitalized infants. Our data supports circulation of HBoV in nosocomial environment during the COVID-19 pandemic.

Human Bocavirus: Detection, Quantification and Molecular Characterization in Sewage and Surface Waters in Uruguay

Human bocavirus (HBoV) infections are related to respiratory and gastroenteric diseases. The aim of this study was to investigate the presence of HBoV in both sewage and surface waters in Uruguay. Sixty-eight sewage samples from the cities of Salto, Paysandú, Bella Unión, Fray Bentos, Treinta y Tres and Melo and 36 surface water samples from the cities of Salto, Florida and Santa Lucía were studied. HBoV was screened by multiplex qPCR for the detection of the four subtypes, followed by monoplex qPCRs for the independent quantification of each subtype. A qualitative PCR followed by DNA sequencing and phylogenetic analysis was carried out for molecular characterization of HBoV strains. HBoV was present in a high frequency (69%) in sewage and only one positive sample (3%) was found in surface water. Concerning sewage samples, HBoV1 was detected in 11 (23%) out of the 47 positives samples, with a mean concentration of 8.2 × 10⁴ genomic copies/Liter (gc/L), HBoV3 was detected in 35 (74%) of the positive samples with a mean concentration of 4.1 × 10⁶ gc/L and subtypes 2 and/or 4 were detected in 39 (83%) of the positive samples with a mean concentration of 7.8 × 10⁶ gc/L. After the phylogenetic analysis performed by a Bayesian approach, the four HBoV subtypes were confirmed. This is the first study determining a high frequency of HBoV and the presence of the four HBoV subtypes in aquatic matrices in Latin America, mainly in sewage. Although HBoV was scarcely detected in surface water, a waterborne transmission is likely to occur if people enter in contact with polluted surface waters for recreational activities such as fishing or swimming since an elevated frequency of HBoV was detected in raw sewage which is usually directly discharged into surface waters.

A prospective study on Aeromonas in outpatients with diarrhea in the central region of Rio Grande do Sul State

Aeromonas spp. were identified in five (2,7%) of 182 diarrheal stool cultures, A. caviae was predominant, resistant mainly to ampicillin and cephalotin. This is the first study showing the presence of Aeromonas spp. in diarrheal stools of outpatients in the central region of Rio Grande do Sul State, Brazil.