Adenovirus Infections and How They Are Treated
Medically reviewed by Jane Kim, MD
Adenoviruses commonly cause cold or flu-like symptoms in humans. Infections tend to be mild and adenoviruses usually don't require treatment.
Adenoviruses can be transmitted from person to person year-round, in people of all ages. They may cause cold-like symptoms such as fever, sore throat, but they can also cause other symptoms such as diarrhea or conjunctivitis (pink eye). In rare cases, they can lead to bronchitis or even pneumonia.
This article discusses adenoviruses, how they spread, what symptoms they cause, and whether or not they require treatment.
Types of Adenoviruses
More than 50 different types of adenoviruses have been identified. The Centers for Disease Control and Protection (CDC) categorizes adenoviruses according to those that can cause outbreaks:
Adenovirus types 3, 4, and 7 are commonly responsible for acute (short-lived) and occasionally severe respiratory infections. Adenovirus types 4 and 7 are known to spread fast in water and have caused outbreaks of febrile disease as well as conjunctivitis in pools that are not adequately treated with chlorine. Adenovirus type 7 has been linked with more severe symptoms and conditions (including death) than any of the other adenoviruses in the U.S.
Adenovirus type 14 has been responsible for outbreaks of acute respiratory illness among military recruits (as well as in the public).
Adenovirus types 8, 19, 37, 53, and 54 cause epidemic keratoconjunctivitis, an eye infection that affects the conjunctivae (the white area of the eye) and the cornea (the clear coating of the eye).
Enteric adenoviruses, types 40 and 41, are known to cause gastroenteritis (an inflammation of the stomach and intestines), particularly in children.
While animals also host types of adenoviruses, humans do not usually contract these from animals.
Explainer
Statistics on the incidence of adenovirus infections are somewhat skewed because these illnesses are not required to be reported to the CDC.
How Adenoviruses Spread
An adenovirus is a very small infectious agent. It can only multiply within the live cells of a host. Adenoviruses are very resilient. They can live for long periods of time outside of the host.
Adenoviruses spread from one infected person to another. These viruses can result in mild illness (such as a respiratory infection), or, less commonly, severe illness (such as meningitis).
People most at risk of getting sick from exposure to an adenovirus are those with a weakened immune system (such as seniors or young children), people with respiratory disorders such as asthma or chronic obstructive pulmonary disease (COPD), and those with heart disease.
There are several common ways to become infected with adenovirus:
Close personal contact (touching or handshakes)
Coughing or sneezing
Touching the nose, mouth, or eyes (without washing your hands) after contact with objects that an infected person has touched or after direct contact with a person infected with the virus
Direct contact with an infected person’s stool (such as when changing a diaper)
Adenoviruses are resistant to many types of cleaners and disinfectants and can live on inanimate objects for long periods of time. If there is an adenovirus case in your household or an outbreak in a facility such as a school or nursing home, it’s important to use a disinfectant known to kill adenoviruses, such as a bleach-based solution.
Adenoviruses in Children
Late winter, spring, and early summer are the most common seasons for adenovirus infections, but they can occur anytime during the year. Children can spread adenoviruses in a few different ways:
Respiratory infections are spread when fluid from the mouth, throat, or lungs that contains the virus is ejected via coughing or sneezing on another person.
Adenoviruses can be spread by touching objects contaminated by an adenovirus (such as toys) and then touching the nose, mouth, or eyes without washing one’s hands. Adenoviruses can live for many hours on toys, countertops, doorknobs, and other inanimate objects.
Digestive tract infections are spread by oral-fecal transmission (not washing hands properly after using the bathroom or eating or drinking food or water that has been contaminated).
Children ages 6 months to 2 years of age who are in childcare facilities on a regular basis are the most likely to contract adenovirus infections. In children under age 5, adenovirus infections most commonly affect the digestive tract. By age 10, most children have had one or more infections caused by an adenovirus.
Adenovirus Symptoms
Adenoviruses can cause various illnesses with a wide range of symptoms.
Common cold and flu symptoms:
Fever or chills
Sore throat
Cough
Shortness of breath or difficulty breathing
Fatigue (tiredness)
Runny or stuffy nose
Body aches or muscle pain
Headache
Acute bronchitis or bronchiolitis (inflammation of the airways of the lungs, sometimes referred to as a “chest cold”) symptoms:
Cough
Mucus production (which could be white, yellowish-gray, or greenish-colored)
Fatigue
Shortness of breath
Low-grade fever and chills
Chest discomfort
Pneumonia symptoms:
Cough (which may be productive, involving yellow or greenish mucus production)
Fever with chills and/or sweating
Shortness of breath (rapid, shallow breathing)
Pain in the chest that is stabbing or sharp and worsens when breathing deep
Fatigue (loss of energy)
Loss of appetite
Conjunctivitis symptoms:
Irritation of the eye or eyes
Photophobia (sensitivity to light)
Watery discharge from the eye or eyes
Sensation of having a foreign body in the eye (due to the involvement of the cornea)
Corneal inflammation
Corneal opacities (loss of normal transparency of the eye due to infection or other causes)
Decreased vision (blurred or hazy) in severe cases
Acute gastritis (inflammation of the stomach or intestines) symptoms:
Nausea and vomiting
Diarrhea
Stomach cramps or discomfort
Symptoms in Children
Adenoviruses commonly cause several types of infections in children, including:
Respiratory conditions
Conjunctivitis
Croup (inflammation and swelling in the area of the vocal cords)
Bronchiolitis (inflammation of the small airways in the lungs)
Pneumonia
Most commonly, children get respiratory conditions from adenoviruses (such as colds, croup, bronchiolitis, and pneumonia), but occasionally they can get infections of the digestive tract (gastroenteritis).
These common symptoms of adenovirus infections in children may begin two to 14 days after exposure:
Cough
Fever
Runny nose
Sore throat
Headache
Swollen glands
Symptoms of conjunctivitis (pink eye)
Vomiting
Diarrhea that becomes watery and starts suddenly
Abdominal cramps
Takeaway
If your child has symptoms of an adenovirus infection, consult with your pediatrician or other healthcare provider as soon as possible for a diagnosis.
Rare Symptoms
Less common symptoms of adenovirus infections could include bladder infections or nervous system infections.
Symptoms of a bladder infection:
Frequent urination
Burning or pain when urinating
Blood in the urine
Symptoms of infection of the brain or spinal cord (such as meningitis and encephalitis):
Nausea and vomiting
Fever
Headache
Stiffness of the neck
Diagnosis
Usually, the healthcare provider will do an examination, take a history of the current symptoms, and make a diagnosis based on this information. If an adenovirus infection causes a sore throat, it’s common for a strep test to be obtained to rule out other underlying causes of the infection.
Special diagnostic tests can be done to detect and identify specific viruses (including adenoviruses) but these tests are expensive. Because there is currently no proven medical treatment for adenovirus infection, it is often considered a waste of time and expense, in addition to the discomfort of obtaining specimens for diagnostic purposes.
On the other hand, if a person is very ill, the healthcare provider may obtain samples from various regions of the body (such as the eyes, throat, stool, blood, or urine) to identify the presence of adenoviruses.
Respiratory Infections
If a test is ordered to evaluate the underlying pathogen (germ) causing a respiratory infection, a specimen will be obtained by swabbing the back of the throat via the nose or the mouth. The swab is sent to the lab for testing.
If a specimen is taken from the nose, the method of testing is referred to as a nasopharyngeal swab. This involves using a special cotton swab to collect a specimen inside both sides of the nose by swabbing for approximately 15 seconds.
An oropharyngeal (throat) specimen may be collected; this involves vigorously swabbing the area around the tonsils and the back of the mouth and throat. The swab is rotated several times.
When a lower respiratory infection (such as viral pneumonia) is suspected, the healthcare provider may ask for a sputum specimen. This involves coughing up some mucus for lab evaluation. A blood specimen could also be ordered to diagnose adenoviruses under some circumstances.
Adenoviral Eye Infections
If there is clinical evidence of conjunctivitis or a corneal eye infection, your healthcare provider may obtain a conjunctival swab specimen for lab evaluation. This is done by using a wood-tipped applicator with a topical numbing agent and normal saline for moisturization.
Takeaway
Specimens for diagnosis of adenoviruses should be collected within seven days of the onset of symptoms.
Adenovirus Treatment
There are no drugs that treat adenovirus, and no specific medical treatment can help clear the infection. Adenovirus can't be treated with antibiotics since it is a virus and not a bacteria.
Most adenovirus infections aren't serious and require minimal intervention to relieve symptoms and prevent complications (such as drinking plenty of fluids to prevent dehydration). Most cases of adenovirus go away within a few days to a couple of weeks.
Treatment of Adenovirus Symptoms in Children
There are some things you can do to help your child feel better while preventing serious complications from the infection. These interventions depend on your child’s age, symptoms, and general health.
Encourage fluids: Water, formula, breast milk, or electrolyte-containing fluids are recommended for rehydration for children. Avoid giving young children sugars, soda, juices, or sports drinks to rehydrate. A child who is unable to drink or hold down fluids is at risk for dehydration and may need to be hospitalized; in this instance, it’s important to consult with a healthcare provider as soon as possible. If needed, intravenous fluids will be given via an IV line (which is administered in a clinical setting). The IV therapy will ensure your child has enough fluids and electrolytes to prevent severe complications, such as dehydration.
Encourage healthy solid foods as tolerated: If your child has diarrhea, consult with the healthcare provider about which types of foods are best.
Give medications as ordered by the healthcare provider: These treat symptoms, such as inhalers (bronchodilators) to help open airways and improve the flow of oxygen in the lungs. Bronchodilators can also be given via a mini nebulizer, which is a machine that delivers a fine mist of medication through a mask placed over the child’s face.
Administer supplemental oxygen if ordered by the healthcare provider: This can be given through a mask, nasal prongs, or an oxygen tent.
Prevention
There is a vaccine for certain types of adenoviruses, but the vaccine is only available to the military. It is not given to the general population because it has not been adequately studied in those with weakened immune systems, infants, children, or people who are pregnant or breastfeeding.
There are some common ways to help to prevent getting ill from the virus:
Meticulous handwashing (Scrub with soap for at least 20 seconds, then rinse with water as hot as can be tolerated.)
Avoiding touching your face, eyes, nose, or mouth (unless you have just washed your hands)
Avoiding close contact with those who are ill
Teaching your children how to adequately wash their hands (the 20-second rule)
Staying home when ill, covering your mouth when you cough or sneeze, and avoiding sharing cups or eating utensils (to help protect others from the infection)
Related: Simple Tips to Prevent Spreading Viruses
Summary
Adenoviruses can cause outbreaks at any time of year. The most common illnesses caused include respiratory illness and viral conjunctivitis.
Adenoviruses spread through close, personal contact, coughing and sneezing, and by contact with infected surfaces or stool.
Adenovirus can cause respiratory symptoms, gastrointestinal symptoms, or eye-related symptoms. There is no specific treatment for adenovirus. Most cases resolve without medical intervention, but sometimes more serious infections such as pneumonia can develop.
