Type-specific clinical characteristics of adenovirus-associated influenza-like illness at five US military medical centers, 2009-2014.

BACKGROUND: Adenovirus is a recognized cause of influenza-like illness (ILI). The proportion of ILI attributable to adenovirus is not known. Moreover, knowledge gaps remain with respect to the epidemiologic, virologic, and clinical characteristics of adenovirus-associated ILI among otherwise healthy individuals. METHODS: An observational, longitudinal study of <65-year-old patients with febrile ILI at five medical centers was conducted from 2009 to 2014. Nasopharyngeal specimens obtained at enrollment were first tested by single-reaction PCR for adenovirus, then further evaluated by a multiplex PCR assay for other respiratory viral pathogens. Symptoms over a 28-day period were collected. RESULTS: We enrolled 1536 individuals, among whom 43 (2·8%) were positive for adenovirus. The median age of cases was 3·4 years (range: 4 months to 41 years). Three were hospitalized. Species and serotype information was available for 33 (76·7%) cases. Species C (n = 21) was the most common, followed by B3 (n = 9) and one each of E4a, D46, and A. Species C infections were more frequent in children (P < 0·01). Half of the cases were positive for at least one other respiratory viral pathogen. Symptoms were generally mild and most commonly included cough (90%), fatigue (79%), rhinorrhea (74%), loss of appetite (71%), and sore throat (64%). Children with non-C adenovirus infection were more likely to report sore throat (P = 0·05) and hoarseness (P = 0·06) than those with species C infection. CONCLUSIONS: Adenovirus is frequently detected with other respiratory viruses. Persons with non-C adenovirus infections reported more severe symptoms, suggesting there may be species-specific differences in virulence and/or host response to infection.

Epidemiology of multiple respiratory viruses in childcare attendees.

BACKGROUND: The identification of multiple viruses during respiratory illness is increasing with advances in rapid molecular testing; however, the epidemiology of respiratory viral coinfections is not well known. METHODS: In total, 225 childcare attendees were prospectively followed for up to 2 years. Nasal swabs were collected at respiratory illness onset and every 7-10 days until illness resolution. Swabs were tested by polymerase chain reaction for 15 respiratory viruses and subtypes. RESULTS: At least 1 virus was detected in 382 (84%) of 455 new-onset illnesses with multiple viruses identified in 212 (46%). The proportion of subject swabs with multiple viruses detected changed as respiratory illnesses progressed from week to week, as did the prevalence of individual viruses. Children with multiple viruses detected at the time of illness onset had less frequent fever (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35, 0.90), however, these children more often had illness symptoms lasting over 7 days (OR, 1.94; 95% CI, 1.20, 3.14). CONCLUSIONS: A high proportion of daycare attendees had multiple viruses detected during respiratory illnesses. Delay between onset of illness and viral detection varied by virus, indicating that some viruses may be underrepresented in studies of virus epidemiology that rely on only a single test at symptom onset.

Human Parechovirus and Other Enteric Viruses in Childcare Attendees in the Era of Rotavirus Vaccines.

OBJECTIVE: We studied the prevalence of enteric viruses, including rotavirus, enterovirus, norovirus, adenovirus, and human parechovirus (HPeV), in stool samples of childcare attendees. The prevalence of enteric viruses was described in children with and those without gastroenteritis. METHODS: Children aged 1-19 months were recruited from 2 childcare centers in Tacoma, Washington, from October 2008 through June 2009. Stool samples were obtained at enrollment and during diarrheal illnesses for enteric virus testing. A symptom diary was completed by parents. RESULTS: One hundred six children (mean age, 10 months) were followed for an average of 170 days. At enrollment, 78 asymptomatic children had stool samples available. Forty-eight illnesses with acute diarrhea (stool samples were available for 24 illnesses) occurred in 37 children. Rotavirus was not detected in samples from symptomatic or asymptomatic children. HPeV was present in 21% and adenovirus in 46% of symptomatic children. At least 1 virus was detected in 78% of samples from asymptomatic children, including HPeV in 27% and adenovirus in 55%. No differences were found in symptom prevalence between HPeV-positive and HPeV-negative diarrheal illnesses. Molecular analysis revealed a diversity of HPeV types. CONCLUSIONS: Our study highlights the high level of HPeV circulation in childcare. The lack of rotavirus detected in this study supports the impact of rotavirus vaccine and emphasizes the need for a greater focus on the epidemiology of non-rotavirus etiologies of gastroenteritis.

Epidemiology of viral respiratory tract infections in a prospective cohort of infants and toddlers attending daycare.

BACKGROUND: The epidemiology of respiratory tract infections (RTIs) in a daycare cohort has not been explored using molecular techniques. OBJECTIVES: (1) Determine the overall incidence of RTIs in a daycare cohort using real-time reverse transcriptase polymerase chain reaction (RT-PCR). (2) Determine the relative incidence and impact of specific respiratory viruses, and characterize and compare clinical features associated with these pathogens. STUDY DESIGN: In this prospective cohort study conducted from February 2006 to April 2008, nasal swabs were obtained from symptomatic children ages 0-30 months enrolled in fulltime daycare. RT-PCR was performed to detect respiratory syncytial virus (RSV), human metapneumovirus (MPV), influenza (Flu) viruses A and B, parainfluenza (PIV), adenovirus (AdV), human coronaviruses (CoV) and rhinovirus (RhV). Symptom diaries were completed for each illness. RESULTS: We followed 119 children (mean age 10 months; range 2-24 months) for 115 child years. The mean annual incidence of RTI per child was 4.2 the first year and 1.2 the second year of the study. At least 1 virus was identified in 67% RTIs. Co-infections were common (27% RTIs), with RhV, CoV, and AdV the most common co-pathogens. PIV was identified in 12% of RTIs with a high incidence of PIV4. The viruses with the greatest impact on our population were RSV, RhV and AdV. CONCLUSIONS: Using molecular techniques, viruses were identified in approximately twice as many RTIs as previously reported in a daycare cohort. Infections with newly identified viruses, such as HMPV and CoV subtypes were less frequent and severe than infections with RSV, AdV and RhV.