Torque Teno Virus (TTV) is a nonpathogenic and ubiquitous ssDNA virus, a member of the Anelloviridae family. TTV has been postulated as a biomarker in transplant patients. This study aimed to determine the TTV species diversity and variability in renal transplant recipients and to associate species diversity with the corresponding TTV viral load. From 27 recipients, 30 plasma samples were selected. Viral load was determined using two real-time PCR assays, followed by RCA-NGS and ORF1 phylogenetic analysis. The TTV diversity was determined in all samples. Variability was determined in three patients with two sequential samples (pre- and post-transplantation). Most of the samples presented multiple TTV species, up to 15 different species were detected. In the pre-transplant samples (n = 12), the most prevalent species were TTV3 (75%) and TTV13 (75%), and the median number of species per sample was 5 (IQR: 4–7.5). TTV3 was also the most prevalent (56%) in the post-transplant samples (n = 18), and the median number of species was 2 (IQR: 1.8–5.5). No significant correlation between the number of species and viral load was found. The number and type of TTV species showed total variability over time. We report high TTV species diversity in Argentinian recipients, especially in pre-transplant period, with total intra-host variability. However, we found no significant correlation between this high diversity and TTV viral load.

Acute respiratory infection (ARI) is one of the principal causes of morbidity worldwide, with respiratory viruses being common etiological agents. Among them, endemic human coronaviruses (hCoVs) including CoV-229E, CoV-OC43, CoV-NL63, and CoV-HKU1 can cause mild ARI but are usually not evaluated in the clinical setting. The aim of this work was to determine the prevalence of all respiratory pathogens, with the focus placed on endemic hCoVs in the pre-pandemic period. Circulating species, clinical associations and coinfections with other respiratory pathogens were evaluated in 510 immunocompetent patients (children and adults) with ARI using the FilmArray® Respiratory Panel (BioFire/bioMérieux). A total of 399 children (252 outpatients and 147 hospitalized) and 111 adult outpatients were enrolled in the pre-pandemic period (2008-2010 and 2016). Endemic hCoVs were the third and fifth more frequently detected viruses among adults and outpatient children, respectively, with an overall frequency close to 10%. The most prevalent species were CoV-OC43 (42.8%) and CoV-HKU1 (40.5%), followed by CoV-NL63 (19.0%) and CoV-229E (4.8%). Tachypnea, wheezing and chest indrawing were more frequent in hospitalized children compared to outpatients. All adult patients presented with symptoms of a common cold. Endemic hCoVs were detected year-round, primarily between June and November. Our results highlight their clinical relevance, and the need to include endemic hCoVs in routine screening. In the post-pandemic period, further long-term surveillance is needed for understanding the epidemiology of endemic hCoVs and their evolution, as a tool to anticipate the possible emergence of new species.