Yes, adenovirus can be spread to others only if the infected person has symptoms. The symptoms of adenovirus include fever, sore throat, cough, runny nose, and conjunctivitis (pink eye). These symptoms can be contagious, so if an infected person has them, then they can spread the virus to others.
Adenovirus is spread through direct contact with the saliva, mucus, or stool of an infected person. It can also be spread through contact with objects that have been contaminated, such as doorknobs, toys, or other surfaces. When an infected person coughs or sneezes, the virus is released into the air and can be inhaled by others nearby.
In addition, adenovirus can be spread through blood or organ transplantation, and through contact with contaminated food or water. In some cases, the virus can even be spread through swimming in public pools.
It's important to remember that adenovirus is highly contagious and can spread quickly, even if the infected person does not show any symptoms. To prevent the spread of adenovirus, it is important to practice good hygiene, such as washing hands frequently and avoiding close contact with those who are infected.