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

Human bocaviruses were first described between 2005 and 2010, identified in respiratory and enteric tract samples of children. Screening studies have shown worldwide distribution. Based on phylogenetic analysis, they were classified into four genotypes (HBoV1-4). From a clinical perspective, human bocavirus 1 (HBoV1) is considered the most relevant, since it can cause upper and lower acute respiratory tract infection, mainly in infants, including common cold, bronchiolitis, and pneumonia, as well as wheezing in susceptible patients. However, the specific processes leading to structural, biochemical, and functional changes resulting in the different clinical presentations have not been elucidated yet. This review surveys the interactions between the virus and target cells that can potentially explain disease-causing mechanisms. It also summarises the clinical phenotype of cases, stressing the role of HBoV1 as an aetiological agent of lower acute respiratory infection in infants, together with laboratory tests for detection and diagnosis. By exploring the current knowledge on the epidemiology of HBoV1, insights into the complex scenario of paediatric respiratory infections are presented, as well as the potential effects that changes in the circulation can have on the dynamics of respiratory agents, spotlighting the benefits of comprehensively increase insights into incidence, interrelationships with co-circulating agents and potential control of HBoV1.

Measles and Rubella Seroprevalence Among Children and Adolescents of Córdoba, Argentina: A Cross-Section Study in the Context of the Elimination Program.

We determined anti-rubella and anti-measles immunoglobulin G (IgG) in 7- to 19-year-old children and adolescents with vaccine only-induced immunity of Córdoba, Argentina, during a 6-month period over 2021-2022. Of the 180 individuals studied, 92.2% and 88.3% were positive for anti-measles and anti-rubella IgG, respectively. No significant differences were found comparing anti-rubella IgG concentrations (p = 0.144) and anti-measles IgG concentrations (p = 0.105) of individuals classified by age, but anti-measles IgG and anti-rubella IgG levels were significantly higher among female individuals compared with males (p = 0.031 and p = 0.036, respectively). Female subjects in the younger age group had higher concentrations of anti-rubella IgG as well (p = 0.020), even when anti-measles IgG concentrations did not differ among female age-subgroups (p = 0.187). In contrast, age subgroups of male individuals did not have significantly different IgG concentrations for rubella (p = 0.745) or measles (p = 0.124). Among samples with discordant results (22/180, 12.6%), 9.1% were negative for rubella but positive for measles; 13.6% were equivocal for rubella and positive for measles; 22.7% were equivocal for rubella and negative for measles, while 54.5% were positive for rubella but negative for measles. The findings indicate a seroprevalence below recommended for preventing measles in the population studied, while they evidence the need for standardization of serological tests for rubella IgG.

Human parvovirus B19 infection in a pregnant patient resulting in severe hydrops, foetal death and persistent infection.

Human parvovirus B19 (B19V) is the aetiological agent of erythema infectiosum. Primary infection during pregnancy can be transmitted to the foetus and cause foetal abnormalities related to depletion of erythrocyte progenitor cells, including congenital anaemia, hydrops, and foetal death. In this paper we report the detection of B19V infection in a pregnant patient, which onset occurred without appreciable signs and symptoms until she developed inappropriate contractions for gestational age and fluid loss. B19V infection resulted in severe hydrops fetalis with a fatal course for the foetus, while persisted in the mother at least 12 months after foetal death. The objective of this report is to highlight the importance of optimizing B19V diagnosis through early suspicion and testing during pregnancy. Knowing the mother's immune status before or at the beginning of gestation can contribute, together with early diagnosis, to improve the management of patients at risk.

Diagnosis and clinical significance of Human bocavirus 1 in children hospitalized for lower acute respiratory infection: molecular detection in respiratory secretions and serum.

Introduction. Human bocavirus 1 (HBoV1) infection occurs with viral genome presence in respiratory secretions (RS) and serum, and therefore both samples can be used for diagnosis.Gap statement. The diagnostic sensitivity of HBoV1 DNA detection in serum and the duration of DNAaemia in severe clinical cases have not been elucidated.Aim. To determine HBoV1 DNA in serum and RS of paediatric patients hospitalized for lower acute respiratory infection (LARI) and to analyse the clinical-epidemiological features of positive cases.Methodology. This was a prospective, transverse study. Physicians selected the clinical situations and obtained paired clinical samples (RS and serum) that were tested by PCR/qPCR for HBoV1. Positive cases were analysed considering time of specimen collection, co-detection, clinical manifestations and viral load; statistical significant level was set at α=0.05.Results. HBoV1 was detected in 98 of 402 cases included (24 %); 18/98 (18 %) patients had the virus detectable in serum and 91/98 (93 %) in RS (P<0.001). Positivity rates were not significantly different in patients with RS and serum collected within or beyond 24 h of admission. Single HBoV1 infection was identified in 39/98 patients (40 %), three patients had HBoV1 in both clinical samples (3/39, 8 %) and 32 (32/39, 82 %) only in RS, 22 of them (69 %) with both clinical samples within 24 h of admission. Cough (P=0.001) and rhinitis (P=0.003) were significantly frequent among them and most patients were diagnosed with bronchiolitis (22/39, 56 %) and pneumonia (9/39, 23 %), which was more frequent compared to cases with co-infection (P=0.04). No significant differences were identified among patients with high, medium or low viral load of HBoV1 regarding rate of positivity in both clinical samples, the time of collection of RS and serum, co-detection, first episode of LARI, clinical manifestations, comorbidity or requirement for assisted ventilation. Intensive care unit (ICU) patients had a significantly higher frequency of detection (P<0.001) and co-detection (P=0.001) compared to patients on standard care.Conclusions. HBoV1 is prevalent among infant patients hospitalized for LARI and including it in the standard testing can add to the aetiological diagnosis in these cases, especially for patients admitted to the ICU. HBoV1 detection in serum did not contribute significantly to the diagnosis as compared to detection in respiratory secretions.