Viruses of the genus Mastadenovirus affects mammals, causing upper respiratory tract infections. There are human, bovine, canine, caprine, equine, murine, ovine, porcine and simian adenoviruses; also one specific to tree shrews.
Adenovirus infections in humans are endemic, particularly among children, but also may cause epidemics of pharyngoconjunctival fever, keratoconjunctivitis, gastroenteritis, and acute respiratory disease (ARD) among military trainees.
Adenoviral infections affect infants and young children much more frequently than adults. Studies have indicated that adenovirus accounts for 3% to 5% of acute respiratory infections in children and is a frequent cause of diarrhea. Although these infections can occur at any time of the year, they are more prevalent in colder months, when children spend more time indoors. Child care centers and schools sometimes experience multiple cases of respiratory infections and diarrhea that are caused by adenovirus.
Febrile respiratory disease, which is an infection of the respiratory tract that includes a fever, is the most common result of adenoviral infection in children. Symptoms include pharyngitis (inflammation of the pharynx, or sore throat), rhinitis (inflammation of nasal membranes, or a congested, runny nose), cough, swollen lymph nodes ("glands"), and flu-like illness. The infection can also cause bronchitis, which is an infection of the mucous membrane linings of the bronchi, or air passages, in the lungs. Sometimes the respiratory infection leads to acute otitis media, infection of the middle ear. In children under age 3, adenovirus often affects the lower respiratory tract as well, causing bronchiolitis, croup, or viral pneumonia, which is less common but can cause serious illness in infants.
Conjunctivitis and pharyngoconjunctival fever caused by adenovirus tend to affect older children in the summer, when they are swimming in pools and lakes. Keratoconjunctivitis is a more severe infection that involves both the conjunctiva and cornea (the transparent front part of the eye). These types of adenoviral infection occur most often in older children and young adults, who may also have a sore throat at the same time. Pharyngoconjunctival fever occurs when adenovirus affects both the lining of the eye and the respiratory tract. Symptoms include very red eyes and a severe sore throat, sometimes accompanied by low-grade fever, rhinitis, and swollen lymph nodes.
Gastroenteritis is inflammation of the stomach and the small and large intestines. Symptoms include watery diarrhea, vomiting, headache, fever, and abdominal cramps. Adenovirus has also been linked to urinary tract infections, which can cause urinary frequency, burning, pain, and blood in the urine.