Adenoviruses are a group of common viruses that can cause a variety of illnesses in humans. They are known to lead to respiratory infections, conjunctivitis (pink eye), and gastroenteritis. These viruses are highly contagious and can spread through respiratory droplets, direct contact, or contaminated surfaces. Infections caused by adenoviruses can affect people of all ages, but they are particularly common in children. Symptoms may include fever, sore throat, cough, and diarrhea. While most adenovirus infections are mild and resolve on their own, some cases can lead to more severe illness, especially in individuals with weakened immune systems.