Adenoviruses are respiratory pathogens, widespread in nature, infecting birds (aviadenoviruses) and many mammals including man (mastadenoviruses). They are highly species-specific. They can can infect the membranes (tissue linings) of the respiratory tract, the eyes, the intestines and urinary tract. Infections can range from asymptomatic to fatal.
In humans, adenoviral infections are a frequent cause of acute upper respiratory tract (URT) infections, i.e. "colds". In addition, they also cause a number of other types of infection including pharyngitis, pneumonia, gastroenteritis, conjunctivitis ("pink-eye") and keratoconjunctivitis in infants and young people, and more rarely acute haemorrhagic cystitis and hepatitis, mainly in infants or in the latter case those with liver disease.
5% of acute respiratory disease in children under 5 years of age is caused by adenoviruses and 10% of the pneumonias. Adenoviral infections are difficult to distinguish from influenza, parainfluenza and RSV. Conjunctivitis can occur with respiratory illness in such cases the disease is called pharyngoconjunctival fever.
Acute respiratory disease (ARD) is commonly seen in military recruits probably due to fatigue and crowding in barracks. Two types of adenovirus (known as 4 and 7) are responsible for these outbreaks and a vaccine is available.
Eye infections characterized by a mild conjunctivitis "swimming pool conjunctivitis" are caused by adenoviruses and have been linked to transmission in contaminated swimming pools.
Adenoviral types 8 and 37 can cause a more severe illness known as epidemic keratoconjunctivitis (EKC). Corneal opacity with concomitant vision loss in 10% of cases.