A little-known virus is spreading steadily across different parts of the world, prompting growing concern among health experts. Often described as “untreatable” because there is no targeted antiviral medicine available, adenovirus is drawing attention due to how tough it is and how quickly it can pass from person to person. Eric Sachinwalla, medical director of infection prevention and control at Jefferson Health, has cautioned that while most healthy individuals develop only mild illness, people in high-risk groups may face more serious health problems. This raises an important question: just how contagious is this mystery illness that is spreading?Adenovirus: How Contagious Is It?Yes, adenovirus is highly contagious and spreads with ease in several ways. It can pass through respiratory droplets released during coughing or sneezing, close physical contact such as hugging or shaking hands, and contact with contaminated surfaces like toys and towels. It can also spread through fecal matter, particularly during diaper changes, and in some cases through water. According to the CDC, the virus spreads quickly in crowded settings such as schools and daycare centres and can survive for long periods on surfaces, making good hygiene especially important for young children and people with weakened immune systems.Who Do Adenoviruses Affect Most?Adenoviruses can infect people of all age groups, but they are most commonly seen in children under the age of five. In babies and young children, the virus often spreads in daycare environments where close contact is common. Children are also more likely to put shared objects in their mouths and may not wash their hands as regularly.Among adults, adenoviruses tend to spread in crowded living conditions. People staying in dormitories or military housing may have a higher risk of infection. The virus is also known to circulate in hospitals and nursing homes, as per CDC.Those with weakened immune systems are more likely to become seriously ill from an adenovirus infection. This includes people who have undergone organ or stem cell transplants, as well as those living with cancer or HIV/AIDS. Individuals with existing heart or lung conditions may also face a higher risk of severe illness.Adenovirus: What Are The Symptoms Of An Adenovirus Infection?The symptoms of an adenovirus infection depend on the part of the body affected. Most commonly, the virus targets the respiratory system. When it infects the airways, it can cause symptoms similar to a cold or the flu. These may include:Cough.Fever.Runny nose.Sore throat (pharyngitis).Pink eye (conjunctivitis).Ear infection (otitis media).Swollen lymph nodes.Chest cold (bronchitis).Pneumonia.Adenoviruses can also infect the digestive system. When this happens, diarrhea may occur, along with gastroenteritis. Gastroenteritis is inflammation of the stomach or intestines and can lead to stomach pain, diarrhea, nausea, and vomiting.In rarer cases, adenoviruses can affect the bladder or the nervous system. Infection of the bladder may result in urinary tract infections. When the nervous system is involved, it can lead to serious conditions affecting the brain, including encephalitis and meningitis.