What Is Adenovirus?

Overview

A runny or stuffy nose, sore throat, cough, and body aches are some flu-related signs and symptoms, but having these symptoms does not always indicate having the flu. Some viral infections, like adenovirus, coronavirus, and the common cold, can also cause flu-like symptoms, which makes it difficult for people to differentiate between these infections and flu, especially during flu season or a pandemic. 

Adenoviruses are a group of widespread viruses that cause a range of illnesses in humans, including respiratory infections, conjunctivitis (pink eye), and gastrointestinal infections. Adenovirus can affect people of all ages but are more common in young children and infants. These viruses do not have a season like other viruses, so infections can occur at any time of the year, and good hygiene practices can help to prevent the spread of the viral infection.¹ 

Causes of adenovirus

Over 50 different types of adenoviruses have been identified by researchers. Certain types are associated with specific illnesses, such as the adenovirus types 3 and 7 cause conjunctivitis, types 4 and 7 cause respiratory tract illness, while types 40 and 41 are associated with gastroenteritis.^2,3 Adenoviruses are primarily spread through close contact with an infected person, respiratory droplets (during sneezing and coughing), contact with contaminated objects, and poor personal hygiene.⁴ Certain populations are more susceptible to adenovirus infections, including young children, people with weakened immune systems, and military recruits living in close quarters. 

Signs and symptoms of adenovirus

The signs and symptoms of adenovirus vary according to the type of virus involved and the part of the body that is infected. The virus most commonly infects the respiratory system, where it causes symptoms similar to the flu or common cold. In some cases, adenovirus infections may not cause any symptoms, while; in other cases, the infections can be severe and may require medical attention.⁵ Here are some of the common signs and symptoms of adenovirus infection:

• Respiratory symptoms: Coughing, congestion, runny nose, sore throat, and fever. In severe cases, pneumonia or bronchitis may develop^5,6,7  
• Eye infections: Conjunctivitis (red or pink colour in the white part of the eye), which can cause redness, irritation, and discharge from the eyes^4,6
• Gastrointestinal symptoms: Abdominal pain, diarrhoea, nausea, and vomiting^6,8

In rare cases, adenoviruses can affect the bladder or nervous system, causing urinary tract infections or neurological symptoms such as meningitis and encephalitis.⁹

Management and treatment for adenovirus

There are no specific treatments or antiviral medicines available for people infected with adenovirus. Most adenovirus infections do not require treatment because of the mild and self-limiting nature of the symptoms. Therefore, symptoms can be managed with rest, hydration (drinking plenty of water), control of nasal secretions with saline washes, over-the-counter fever-reducing medication and pain relievers, in addition to good hygiene to prevent the spread of the infection.¹⁰ However, in severe cases, hospitalisation might be necessary for supportive care, such as IV fluids, oxygen therapy, and treatment with an antiviral medication like cidofovir.¹¹

FAQs

How is adenovirus diagnosed?

Adenovirus can be diagnosed primarily by clinical evaluation of the person's symptoms. Sometimes, doctors request chest X-rays, blood tests, stool cultures, or nasal swabs to confirm the diagnosis.¹⁰ In addition, molecular detection of adenovirus is often performed through laboratory tests, like polymerase chain reaction (PCR) and serology tests. The PCR test uses a sample of body fluid (blood, urine, or respiratory secretions) to detect the genetic material of the virus, while the serology test involves measuring the levels of antibodies to adenovirus in the blood, which helps to determine if someone has been infected with adenovirus in the past or is currently infected. In addition, adenovirus can be isolated by taking a sample of body fluid and growing the virus in a laboratory dish.^12,13

How can I prevent adenovirus?

There are several measures you can take to reduce your risk of infection and spreading the virus to others:⁴

• Practice good hygiene: Frequent hand washing with soap for at least 20 seconds or use hand sanitiser, avoid touching your face with uncleaned hands, cleaning of personal items like utensils, cups, towels, and disposal of contaminated facial tissue.
• Avoid close contact with sick people: Adenovirus can spread through respiratory secretions, so avoid close contact with people having respiratory symptoms such as coughing and sneezing.
• Stay home when you feel unwell: If you have symptoms of adenovirus infection, stay home until you are no longer contagious to prevent the spread of infection.
• Keep surfaces clean: Use a disinfectant to clean surfaces that might be contaminated with adenoviruses, such as doorknobs, counters, and phones.
• Boost your immune system: Maintaining a healthy immune system through regular exercise, a balanced diet, and adequate fluids and sleep can help reduce your risk of getting adenovirus or other infections.     

Who is at risk of adenovirus?

Adenovirus can infect anyone and develop symptoms; however, certain populations may be at higher risk for severe infection, including people with weakened immune systems, people with underlying medical conditions such as asthma, chronic obstructive pulmonary disease (COPD), or heart disease, and infants and young children. In fact, adenovirus infections are more common in children under 5 years old than in adults. Young children are particularly susceptible to adenovirus because their immune systems are not yet fully developed, making it easier for the virus to infect their cells. In addition, children at this age are more likely to put toys into their mouths, come into contact with infected children, and are less likely to practice good hand washing.^1,3,14 

How common is adenovirus?

Adenovirus infections are most common during the late winter, spring, and early summer months.¹⁵ Infections occur worldwide and affect people of all ages. However, the incidence of adenovirus infection increases in crowded situations such as military recruits, nursing homes, schools, children’s daycare facilities, prisons, and swimming pools.^4,16

Is adenovirus contagious?

Adenovirus is highly contagious and can readily spread from person to person, especially during the first few days of the symptoms. Infected people are most contagious when they have symptoms, but they can also spread the virus before symptoms appear and after symptoms have resolved.⁴

When should I see a doctor?

Although adenovirus infections are usually mild and resolve on their own without medical treatment, you should see a doctor if you have a weakened immune system or are experiencing any of the following symptoms:

• Difficulty breathing or shortness of breath
• Chest pain or pressure
• High fever
• Severe headache or neck pain
• Persistent vomiting or diarrhoea
• Dehydration
• Worsening of the symptoms after an initial improvement
• Symptoms that last more than 10 days

Summary

Adenovirus is a common virus that causes a range of illnesses, from mild respiratory symptoms to severe infections such as pneumonia and meningitis. The virus is highly contagious and can readily spread from person to person. Babies, young children, people with weakened immune systems, and people with underlying medical conditions are at higher risk for severe adenovirus infection. Mild cases can typically be managed at home with rest and over-the-counter medications, while severe cases may require hospitalization. To prevent the spread of adenovirus, practice good hygiene, such as washing your hands frequently, covering your mouth and nose when coughing or sneezing, avoiding close contact with sick people, and keeping surfaces clean.