Human bocavirus (HBoV) is a new parvovirus associated with acute respiratory tract infection (ARTI). In order to evaluate HBoV significance as an agent of acute respiratory disease, we screened 1,135 respiratory samples from children and adults with and without symptoms during two complete calendar years. HBoV1 prevalence in patients with ARTI was 6.33 % in 2011 and 11.64 % in 2012, including neonatal and adult patients. HBoV1 was also detected in 3.77 % of asymptomatic individuals. The co-detection rate was 78.1 %. Among children, 87 % were clinically diagnosed with lower respiratory infection (no significant differences between patients with and without coinfection), and 31 % exhibited comorbidities. Pediatric patients with comorbidities were significantly older than patients without comorbidities. Patients with ARTI had either high or low viral load, while controls had only low viral load, but there were no clinical differences between patients with high or low viral load. In conclusion, we present evidence of the pathogenic potential of HBoV1 in young children with ARTI. Since patients with HBoV1-single infection are not significantly different from those with coinfection with respect to clinical features, the virus can be as pathogenic by itself as other respiratory agents are. Furthermore, an association between high HBoV1 load and disease could not be demonstrated in this study, but all asymptomatic individuals had low viral loads. Also, children with comorbidities are susceptible to HBoV1 infection at older ages than previously healthy children. Thus, the clinical presentation of infection may occur depending on both viral load and the particular interaction between the HBoV1 and the host.

Human herpesvirus-8 (HHV-8) causes Kaposi's sarcoma (KS) and lymphoproliferative disorders in both HIV-infected and uninfected patients. HHV-8 has a worldwide occurrence but infection rates vary according to a combination of geographic and behavioral risks. The main transmission route seems to be sexual, nevertheless, nasal secretions, saliva, blood, and organ graft have been proposed. HHV-8 was postulated as a new infectious agent for screening in blood donors. The aim of this study was to evaluate the prevalence of antibodies against HHV-8 antigens in blood donors of South America. Serum samples from 2,470 blood donors from Argentina, Brazil, and Chile corresponding to five geographic regions were studied by indirect immunofluorescence assay (IFA). Seroprevalence rate was 3.7% (92/2,470; 95% CI 2.9-4.5) in the entire blood donor population distributed as follows: Argentina, 4.0% (Buenos Aires city, 4.3%; Bahia Blanca, 2.4%; and Córdoba, 4.0%), Campinas (Brazil), 2.8%; and Santiago de Chile, 3.0%. There was no difference (P>0.05) between men and women or age related, except in Brazil where positive cases were 30-49-year-old males. The present study, which includes different geographical areas of multiple countries from South America, has not been done before. The results show similar prevalence rates among the studied zones corresponding to low-prevalence regions. South America is a large sub-continent with a wide spectrum of population and geographical characteristics, thus, more HHV-8 prevalence studies should be necessary to establish possible regional differences.

A B S T R A C T Human bocavirus (HBoV) is a parvovirus whose association with respiratory disease is currently under investigation.Objective: To determine HBoV prevalence in children with lower acute respiratory infection. Results: The general prevalence of HBoV was 21.5% and the positive cases (HBoV+) were more frequent during winter and spring. The mean age of HBoV+ patients was 6.9 months, with 87.1% of the detections corresponding to infants less than 1 year old (among which the prevalence of HBoV was 26.3% in patients < 3 months of age, 22.1% in 3 to 6 months, 25.3% in 6 to 9 months, and 18.8% in 9 to 12 months). The sequence analysis of the NP1 coding region of 15 isolates showed that all isolates from Cordoba were HBoV1 which exhibited a homology of nearly 100% both among themselves and with the originally discovered virus from 2005. Conclusion:Overall, our results indicate that HBoV is a significant pathogen that contributes to acute respiratory infection both on its own and during coinfection with other viruses.

Instituto de Virología 'Dr J. M. Vanella', Facultad de Ciencias Mé dicas, Universidad Nacional de Có rdoba, ArgentinaHuman bocavirus (HBoV) is a parvovirus with a possible aetiological role in respiratory disease that is currently under investigation. We detected HBoV1 in children and adults hospitalized with acute disease of the lower respiratory tract. HBoV genome was detected by PCR in nasopharyngeal swabs collected from 75 patients aged 0-89 years during 2010. HBoV was found in 17/75 (22.7 %) patients, 64.7 % of them infants younger than 1 year old and 29.4 % adults older than 30 years [the bimodal age distribution among HBoV-positive (HBoV + ) patients was statistically significant, P,0.001]. Of all HBoV + cases, 35.3 % were co-infected; all coinfections occurred in children (¡13 years old) and 83.3 % of them were HBoV-respiratory syncytial virus (RSV) co-infections. Among infants younger than 1 year, 50 % HBoV + specimens were co-infected, all of them with RSV. The rate of co-infection in infants was significantly higher compared to the frequency of co-infection in the whole cohort (P50.003). The results suggest that HBoV1 is involved in acute respiratory disease. Interplay between HBoV1 and RSV cannot be discarded as a cause of elevated percentages of co-detections in infants. INTRODUCTIONHuman bocavirus (HBoV) is a parvovirus first identified in 2005 in nasopharyngeal aspirates of children with lower respiratory tract infection (Allander et al., 2005). Since then, it has been associated with upper and lower acute respiratory infection (ARI), a leading cause of acute illnesses worldwide and the most important cause of mortality in infants and young children and disabilityadjusted life-years lost in developing countries (Simoes et al., 2006; WHO, 2009). To date, four species of HBoV have been proposed, and the name human bocavirus 1 (HBoV1) was suggested for the originally discovered virus. HBoV1 is linked to respiratory disease, while it is believed that HBoV2-4 are associated with gastroenteritis (Kapoor et al., 2010). With a ubiquitous distribution, the presence of HBoV DNA has been reported mostly in children with ARI in a variable range from 1.5 to 19 % (Allander, 2008), although recently even higher prevalence (33 %) has been observed in ill children (Martin et al., 2010). Although the virus is associated with ARI, the elevated rates of coinfection with other respiratory viruses with well-established pathogenic potential (Kaplan et al., 2006;Allander et al., 2007;Fry et al., 2007; Gerna et al., 2007;Kleines et al., 2007; Christensen et al., 2008 Christensen et al., , 2010Cilla et al., 2008;Pilger et al., 2011), the detection in asymptomatic individuals (Christensen et al., 2010) and the possibility of a persistent infection (Martin et al., 2010) make it difficult to allocate a causative role for HBoV in respiratory disease. Not only is the aetiological capacity of HBoV under investigation, but the natural history of the infection is still unknown. In addition, the impact of HBoV on the global epid...

Human Metapneumovirus (hMPV) is responsible for acute respiratory infections in humans, with clinical and epidemiological relevance in pediatric, elderly, and immunocompromised populations. These features are largely unknown in Córdoba, Argentina and in adults in general. Hence, our goal was to broadly characterize hMPV infection in patients of all ages hospitalized with acute respiratory infections in Córdoba, Argentina, including epidemiology, clinical features and genetic diversity. Nasopharyngeal secretions were obtained from 795 patients during 2011–2013, 621 patients were 0–25 years old and 174 were 26–85 years old. HMPV was assayed by RT-PCR and other respiratory viruses by indirect immunofluorescence. Local strains were identified by sequence analysis. Human Metapneumovirus was detected in 20.3% (161/795) patients, 13.1% as single infections and 7.2% in co-infections, more frequently with Respiratory Syncytial Virus. HMPV circulated during late winter and spring in all age patients, but mainly in children under 4 years old in 71.4% (115/161) and adults between 26 and 59 years old in 12.4% (20/161). The most prevalent diagnosis was mild acute respiratory infection in 59.6% (96/161) and bronchiolitis in 9.3% (15/161). Local strains were clustered within A2 subtype; they presented 73–100% identities among them, showing a high degree of homology compared to isolations from neighboring countries. We demonstrate that hMPV circulated among all age patients with respiratory infection during 2011–2013 in Córdoba, contributing to the understanding of this virus, its diagnosis and patient handling in local health-care centers.

Overall, our results indicate that HBoV is a significant pathogen that contributes to acute respiratory infection both on its own and during coinfection with other viruses.

SUMMARYThis work presents the results of the detection of antibodies (immunoglobulin G) for subtypes I and VI of VEE viruses complex (Togaviridae family) in people from the General Belgrano island, Formosa province (Argentina). The prevalence of neutralizing (NT) antibodies for subtype VI was from 30% to 70% and the prevalence of antibodies inhibitory of hemagglutination (HI) was of 0% in the first and second inquiry respectively. For the subtype IAB the prevalence of NT antibodies was from 13% to 3.6%, similar to the prevalence total for both subtypes. HI antibodies were not detected in any inquiries for any subtype. It was observed that both subtypes circulate simultaneously, while subtype VI remains constant with some peaks, subtype I was found in low level.

The neuroinvasiveness of Junin virus depends on the viral strain, animal species, and age. The role of infected blood cells in hematogenous Junin virus spread to the central nervous system (CNS) was studied by determining the growth in pheripheral mononuclear cells and brain tissue of Candid 1 and XJCL3 laboratory strains, in Calomys musculinus and guinea pigs. The present study demonstrated that Junin virus replicates in circulating peripheral lymphocytes and macrophages of 11-day-old guinea pigs and 6 +/- 1-day-old Calomys musculinus. Moreover, the observation that mononuclear phagocyte depletion did block Junin virus neuroinvasion firmly indicates that the cellular viremia (circulating monocytes) is one of the mechanisms of Junin virus attenuated strains spread to the CNS in animal hosts.