adenovirus

introduction

human adenoviruses are a group of common viruses with a wide range of clinical manifestations
it is also an important pathogen in immunocompromised patients such as post-transplant
there are 51 serotypes currently recognized, classified into 6 species (A-F)
pattern of illness tends to be species and/or serotype specific
can be rapidly spread in closed environments through respiratory secretions and potentially through contaminated surfaces
80% of patients with HAdV infection are younger than 5 years but it often infects adults as well, especially the elderly and the immunocompromised
Almost all humans are infected at least once by the time they complete their sixth year of life. These infections, especially with HAdV A and D, are mild or asymptomatic. Such infections comprise a tenth of childhood respiratory infections, mostly due to HAdV types 1-7.

mainly adenovirus types 1, 2, 4, 5, and 6; occasionally, 3 and 7
50% are subclinical
highly contagious as secretions or saliva contain very high concentrations of viral particles and in non-immune persons only 5 particles may be needed to start infection
usually presents as coryza lasting 3-5 days
may present as acute bronchitis - bronchitis with conjunctivitis suggests adenoviral infection
may cause prolonged fevers, raised CRP
uncommonly causes encephalitis, hepatitis, and myocarditis
rarely causes pneumonia - may be fatal in neonates - usually with serotypes 3, 7, 14, 21, and 30

is suspected to be due to the coinfection of HAdV and adeno-associated virus (AAV), the latter being the actual pathogenic agent in this case

mainly serotypes 3, 4, and 7
usually school aged children, often on summer school camps or in military trainees where swimming in lakes or dams may be mode of spread
acute conjunctivitis occurs with or without pharyngitis or a respiratory syndrome
incubation period is 5 days
self-limited to 5 days
may also develop exanthem, diarrhoea and rarely, encephalitis