Adenovirus (AdV) can cause severe respiratory infections in children and immunocompromised patients, but less is known about severe AdV pneumonia in immunocompetent adults. In this retrospective study, we compared respiratory tract infections and pneumonia caused by AdV in immunocompromised and immunocompetent adult patients regarding clinical presentation and severity of infection. The results show that AdV can cause severe infections in both immunocompetent and immunocompromised patients, and the clinical presentation and need for hospitalisation, mechanical ventilation and antiviral treatment were equal in both groups. No underlying risk factors for severe AdV infection in healthy individuals were identified.

Adenoviruses are found everywhere in the environment, and cause various health problems including symptoms of enteric illness, and respiratory illness. Despite their significance to public health, few studies have addressed the health risks associated with exposure to adenovirus. Human challenge studies have been published for a few adenoviruses, which involved exposure through oral ingestion, inhalation, intranasal and intraocular droplet inoculation. Nothwithstanding the different symptoms resulting from such exposures, infection can be defined as colonization of a corresponding mucosa. A two-level dose-response model was developed to describe the distributions of infectivity and pathogenicity in various challenge studies of adenovirus, incorporating differences in inoculation route as shift in average infectivity and pathogenicity. This dose-response model can be used to make predictions for the infectivity of adenovirus, specific to any of the four studied inoculation methods. The generalized adenovirus dose-response relationship for infection and acute illness takes into account variation in infectivity and/or pathogenicity across adenovirus types, as well as uncertainty due to limited data.

Human adenoviruses (HAdVs) are important respiratory pathogens, found in 2–27% of acute respiratory infection (ARI) cases. Few studies have analysed the diversity of species and types of HAdVs associated with ARI in Brazil. The purpose of this study was to determine the circulation patterns of the different HAdV species and respective types associated with ARI in children in the city of Fortaleza, northeastern Brazil. HAdVs were screened by an indirect immunofluorescence assay, and subsequently identified as species and types by PCR and sequencing of the hexon gene (HVR1–HVR6). Between 2001 and 2013, a total of 290 HAdV strains were detected, 190 of which were identified as belonging to the HAdV-B, -C and -E species. Seven types of HAdVs circulated in the studied population during the analysed period, with HAdV-3 being predominant.

In response to an alert due to epidemic gastroenteritis in children in a kindergarten, an outbreak investigation was carried out in a Portuguese municipality. The objectives were to establish an aetiological diagnosis, assess vaccine efficacy if possible, and to take corrective measures if necessary. The warden at the kindergarten was interviewed, and we visited the premises. The overall attack rate was 11·4% and most cases were mild. Stool samples from three symptomatic children were collected and screened for the presence of noroviruses, rotaviruses and adenoviruses. High vaccination coverage against rotaviruses was recorded in children aged <2 years. We initially thought that noroviruses and rotaviruses were more likely to have been the aetiological cause of the disease, but the outbreak was caused by infection with adenovirus 41. These viruses should not be overlooked in the laboratory protocol in the study of acute gastroenteritis outbreaks.