Adenoviruses are a group of common viruses that can infect individuals of all ages. They are a diverse family with over 50 types known to cause illness in humans. These viruses circulate year-round, unlike seasonal viruses like influenza. Infections can lead to a wide spectrum of illnesses, most of which are mild and resolve on their own. The resulting sickness can manifest in several different ways depending on the specific type of virus involved.
Common Illnesses Caused by Adenovirus
Respiratory Illnesses
The most frequent manifestation is respiratory illness, with symptoms mirroring the common cold or flu. These infections can affect the upper and lower respiratory tract. Symptoms include a sore throat, fever, and a runny nose. The virus can also lead to acute bronchitis, an inflammation of the lungs’ airways often called a “chest cold,” which causes a persistent cough.
In some cases, particularly in young children, adenoviruses can cause croup, an infection of the upper airway that obstructs breathing and causes a distinctive barking cough. For some individuals, the infection can progress into the lower respiratory system and cause pneumonia. These conditions can range from mild to severe enough to require medical attention.
Gastrointestinal Illnesses
Certain adenovirus types target the gastrointestinal system, causing acute gastroenteritis, an inflammation of the stomach and intestines. Primary symptoms are diarrhea and vomiting. Individuals may also experience stomach cramps and nausea.
Adenovirus-induced gastroenteritis is a common cause of diarrheal illness in young children. Symptoms appear a few days after exposure and can last for one to two weeks. Dehydration is a primary concern due to fluid loss from vomiting and diarrhea, making fluid replacement an important part of managing the condition at home.
Conjunctivitis
Adenovirus is a frequent cause of conjunctivitis (pink eye). This is an inflammation of the conjunctiva, the thin, transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. Adenoviral conjunctivitis is highly contagious and causes redness in one or both eyes.
Other symptoms include itchiness, a gritty feeling in the eye, and a watery discharge. A person with adenoviral conjunctivitis may also experience a sore throat and fever, a combination known as pharyngoconjunctival fever. The infection spreads easily from one eye to the other or to other people through contact with eye secretions.
Transmission and High-Risk Populations
Adenoviruses are highly contagious and spread through several common routes:
- Close personal contact, such as touching or shaking hands with an infected person.
- Airborne droplets released when an infected person coughs or sneezes.
- Touching a contaminated surface and then touching your mouth, nose, or eyes. Adenoviruses are resilient and can survive on surfaces for extended periods.
- Contact with contaminated water, such as in swimming pools, or an infected person’s stool.
Certain groups are at a higher risk of contracting an adenovirus. Young children, especially those in daycare or school settings, are susceptible due to frequent close contact and less developed immune systems. By age 10, most children have had at least one adenovirus infection.
Individuals with weakened immune systems are also at a higher risk. This includes people with conditions like HIV/AIDS, cancer patients undergoing chemotherapy, or organ transplant recipients. People with pre-existing cardiac or respiratory diseases also face an elevated risk.
Management and Prevention
No specific antiviral medications exist for treating adenovirus infections. Management, therefore, focuses on supportive care to relieve symptoms while the body’s immune system fights off the virus. Most infections are mild and can be managed at home.
Getting adequate rest and staying well-hydrated are fundamental to recovery. Over-the-counter medications can be used to manage symptoms like fever and pain. It is important to use these medications as directed and consult a healthcare provider with any concerns, especially when caring for children.
Preventing the spread of adenovirus involves straightforward hygiene practices. Frequent and thorough handwashing with soap and water is one of the most effective methods. It is also important to avoid touching the eyes, nose, and mouth, as this is a primary way the virus enters the body.
When a person is sick, they should stay home to avoid transmitting the virus to others in the community or workplace. Since adenoviruses can be resistant to some common disinfectants, cleaning surfaces with effective products is also a useful preventive measure.
Potential for Severe Disease
While most adenovirus infections are mild, severe disease can occur. Infants and individuals with compromised immune systems are at the greatest risk for complications. In these groups, the virus can lead to severe pneumonia or bronchitis that requires hospitalization.
Beyond respiratory complications, adenoviruses can, in rare instances, cause neurological diseases affecting the brain and spinal cord. Some people with weakened immune systems may experience ongoing, asymptomatic infections where they continue to shed the virus for weeks or longer.
Scientific investigations have explored a possible link between adenovirus type 41 and unexplained cases of acute hepatitis in children, though this is an area of active research. Seek medical attention if symptoms are severe, such as difficulty breathing, signs of dehydration, or a high fever that does not improve.