What are the other Names for this Condition? (Also known as/Synonyms)

• Infection by Adenovirus

What is Adenovirus Infection? (Definition/Background Information)

• Adenovirus is a small infectious agent that causes upper respiratory tract infections, conjunctivitis (eye infection), and other infections in humans. It generally affects the membranes of the respiratory tract, eyes, intestines, and urinary tract
• Adenoviruses are responsible for about 10% of the respiratory infections in kids and are one of the common reasons for diarrhea. The infection is highly contagious and spreads from one individual to another through physical contact
• Infection by Adenovirus can occur anytime throughout the year, but certain illnesses caused by adenovirus, occur only during certain times of the year and mostly affects children of a particular age
• The common signs and symptoms exhibited by Adenovirus Infection would include fever, sore throat, runny nose, headaches, cough, skin rashes, diarrhea, and urinary symptoms
• A supportive and symptomatic treatment may be provided. Mild infections tend to last for a week, while severe infections may last for a couple of weeks. The prognosis of Adenovirus Infection depends on the severity of its signs and symptoms

Who gets Adenovirus Infection? (Age and Sex Distribution)

• Any individual irrespective of age, gender, race, ethnicity, or geographical location can be affected by Adenovirus Infection
• Nevertheless, the infection is normally seen in children - from infants to school age, although children of any age can be affected, including neonates
• Most children would have had an occurrence of Adenovirus Infection, at least once before they are 10 years old
• Young adults in close contact settings, such as military camps and dormitories, are also likely to be easily infected
• Adenovirus Infection can occur at any time during the year, though:
  • Respiratory tract infections caused by adenovirus are more common in the winter, spring, and early summer
  • Conjunctivitis and pharyngoconjunctival fever (conjunctivitis with sore throat) caused by adenovirus mostly occur in older kids, during summer

What are the Risk Factors for Adenovirus Infection? (Predisposing Factors)

The risk factors for Adenovirus Infection include:

• Age:
  • Babies and young children are more commonly affected by adenovirus and it mostly infects children in their first year of life
  • Digestive tract infection caused by adenoviruses occurs mostly in children under the age of 4 years             
• Season:
  • Certain diseases caused by adenovirus occur in some seasons, such as acute respiratory disease (fever and sore throat), occurs mainly in early summer, winter, and spring
  • Conjunctivitis and pharyngoconjunctival fever caused by adenovirus mostly occur in older kids during summer  
• Immunosuppressed individuals: The infection can easily affect individuals with poor immune systems such as:
  • HIV/AIDS patients
  • Patients taking chemotherapy drugs for cancer treatment
  • Patients under immunosuppressant medications after organ transplantation  
• People living in close quarters and confined spaces, such as schools, summer camps, hostels, prisons, and military camps, are at a high risk for acquiring Adenovirus Infection, because it is a highly contagious viral infection

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Adenovirus Infection? (Etiology)

• Adenovirus is a small DNA virus that causes a variety of infections in humans. The most common infection caused by adenovirus is respiratory tract infection
• But depending upon the infecting serotype, they may also cause various other infections such as adenovirus gastroenteritis (infection of the food pipe), adenovirus conjunctivitis (eye infection with red eyes), adenovirus cystitis (infection of the urinary bladder) and adenovirus rashes

Adenovirus Infection spreads from one individual to another through physical contact such as:

• Respiratory secretions (sneezing, coughing, and even spitting)
• Fecal contaminations via
  • Contaminated water
  • Eating food contaminated by houseflies
  • Poor hand washing habits
  • The infection can also spread by drinking contaminated water             
• Indirect transmission can also occur through
  • Exposure to contaminated surfaces of furniture and other objects
  • By touching the eyes/nose/mouth with contaminated hands that has not been washed properly
  • Adenovirus causing pink eye is transmitted by water in lakes and swimming pools, and also by sharing contaminated objects such as towels, toys, etc             

Adenovirus Infection is very contagious during the first few days of symptoms. In certain cases, the infected individuals can be potentially contagious for a longer period of time (sometimes even for months).

What are the Signs and Symptoms of Adenovirus Infection?

The signs and symptoms of Adenovirus Infection start appearing at different times for the different types of illnesses, caused by the virus:

• For airway infection, the symptoms will show within 2-14 days after exposure to the virus
• For intestinal infection, the symptoms start appearing within 3-10 days after exposure to the virus

The signs and symptoms will also differ depending upon the illness caused by the virus:

• Respiratory tract infection signs and symptoms include:
  • Runny nose
  • Sore throat, cough
  • Fever, headache
  • Swollen lymph nodes
  • General uneasiness          
• Intestinal tract infection signs and symptoms include:
  • Watery diarrhea
  • Fever
  • Abdominal pain and tenderness
• Genitourinary tract infection signs and symptoms include:
  • Frequent urination, burning pain while urinating
  • Blood in urine, also termed as hemorrhagic cystitis             
• Eye infection (pink eye or conjunctivitis) signs and symptoms include:
  • Redness  of the eyes, eye irritation
  • Discharge from the eyes             
• Pharyngoconjunctival fever signs and symptoms include:
  • Very red eyes
  • Severe sore throat
  • Low-grade fever
  • Rhinitis (nasal congestion and runny nose)
  • Swollen lymph nodes

• The signs and symptoms of keratoconjunctivitis (infection that involves both the conjunctiva and the cornea of the eyes) include:

  • Red eyes
  • Photophobia: Difficulty when bright light is flashed
  • Blurred vision
  • Discharge from the eyes, pain in the eyes       

How is Adenovirus Infection Diagnosed?

The diagnosis of Adenovirus Infection may include:

• Complete evaluation of medical history along with a thorough physical exam, with special emphasis on the lung and eye
• The following tests can be done to detect the presence of adenovirus:
  • Adenovirus antigen detection test
  • Adenovirus polymerase chain reaction assay
  • Adenovirus isolation through viral cultures
• The family physician will recommend the testing of:
  • Respiratory secretions
  • Conjunctival secretions
  • Stool specimens
  • Blood and urine samples             

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Adenovirus Infection?

Complications due to Adenovirus Infection could include:

• Severe pneumonia, which can be life-threatening
• Bronchiolitis obliterans: An inflammatory process in which the small airways are replaced by scar tissues that may lead to reduction in the lung volume and decreased lung compliance
• Otitis media (middle ear infection)
• Meningitis: Infection of the brain coverings
• Individuals with weak immune system are likely to be affected by severe infections
• Intussusception: A medical condition in which one part of the intestine slides over the other, causing blockage of the intestine with severe abdominal pain

How is Adenovirus Infection Treated?

Currently, only supportive and symptomatic treatment is available for Adenovirus Infection, with no specific treatment against the virus. Besides, these viral infections are mostly mild in nature and they can resolve on their own without requiring any treatment.

• Supportive and symptomatic treatment measures include:
  • Adequate bed rest and plenty of fluids
  • Infected individuals are kept isolated from others to prevent the spread of the disease, until there is a complete recovery
  • Over-the-counter medicines, such as acetaminophen and paracetamol, for relieving fever, may be given upon the physician’s recommendation
  • Aspirin is not recommended in children due to the risk of Reye syndrome, which is a life-threatening condition             
• Severe nose blockages and running nose can be relieved by using:
  • Cool mist humidifiers
  • Airway dilator medicines
  • Nasal saline drops and bulb syringe can be used to clear the nose in infants, less than 6 months old
• For severe diarrhea and vomiting:
  • The patients are advised to take lots of fluids
  • Oral rehydration solution may be recommended             
• For pink eye or conjunctivitis:
  • Warm compresses may relieve the symptoms
  • Topical eye ointment and drops can be used to minimize the effects of the symptoms  

How can Adenovirus Infection be Prevented?

Currently there are no preventive methods available to prevent Adenovirus Infection. However, the following measures may be beneficial:

• Implementation of good and effective infection control practices
• Maintaining adequate level of chlorine in the swimming pools and lakes
• Frequent hand washing especially:
  • Before and after using the toilet
  • Before preparing food
  • Before eating
  • After handling dirty diapers          
• Good health habits should be followed such as:
  • Covering the mouth and nose while sneezing or coughing
  • Using an alcohol-based hand sanitizer
  • Avoiding touching the eyes, nose, and mouth with contaminated (unclean) hands

  • Close contact with infected people should be avoided (this applies particularly for small children and elderly adults with weak immunity)

• The infected individual needs to be isolated from other healthy individuals to prevent the spread of the disease
• Avoid sharing spaces and items of infected individuals

What is the Prognosis of Adenovirus Infection? (Outcomes/Resolutions)

• Most immune competent individuals with Adenovirus Infection recover fully, within a few days even without any treatment; though, cough and eye infection may persist for a longer time period
• It is only those individuals with weak immune system who are likely to develop complications, such as pneumonia, respiratory failure, multiple organ failure, which may result in death
• Some individuals can carry the virus in their tonsils, adenoids, and intestines for months and even years, without the presence of any symptoms

Additional and Relevant Useful Information for Adenovirus Infection:

In the year 1971, adenovirus vaccine which was safe and effective in controlling the effects of adenovirus serotypes 4, 7 (that cause acute respiratory disease) was implemented among military recruits. This vaccine helped in controlling outbreaks of the disease. But, due to economic non-feasibility, the production of this vaccine was stopped in 1996. This led to an increase in the incidence of acute respiratory disease caused by adenoviruses.