Adenoviruses are a group of viruses that can infect the membranes (tissue linings) of the respiratory tract, the eyes, the intestines, and urinary tract. The signs and symptoms of adenoviral infections vary depending on which part of the body is affected.
- 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 (or pinkeye) is an inflammation of the conjunctiva (membranes that cover the eye and inner surfaces of the eyelids). Symptoms include red eyes, a discharge, tearing, and the feeling that there is something in the eye. 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.
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.
However, conjunctivitis and pharyngoconjunctival fever caused by adenovirus tend to affect older children in the summer, when they are swimming in pools and lakes.
Once a child is exposed to adenovirus, symptoms can develop from 2 days to 2 weeks later.
Most adenoviral infections last from a few days to a week. Severe respiratory infections may last longer and cause lingering symptoms, such as a cough. Pneumonia can last anywhere from 2 to 4 weeks. In cases of pharyngoconjunctival fever, sore throat and fever may disappear within a week, but conjunctivitis can persist for another several days to a week.
Adenovirus is highly contagious, as indicated by the occurrence of multiple cases in situations where close contact is common, such as child care centers, schools, hospitals, and summer camps. The types of adenovirus that cause respiratory and intestinal infections spread from person to person through respiratory secretions (coughs or sneezes) or fecal contamination. A child also might pick up the virus by holding hands or sharing a toy with an infected person. Indirect transmission can occur through exposure to the contaminated surfaces of furniture and other objects.
The types of adenovirus causing conjunctivitis are often transmitted by water (in lakes and swimming pools), by sharing contaminated objects (such as towels or toys), or by touch.
There is no way to completely prevent adenoviral infections in children. To reduce the risk of transmission, parents and other caregivers should encourage frequent hand washing, keep shared surfaces such as countertops and toys clean, and remove children with infections from group settings until symptoms subside.