RSV:

RSV is caused by the Respiratory Syncitial Virus and it causes respiratory tract infections in all persons. RSV is the major cause of lower respiratory tract infections in infants and children. RSV infection typically occurs during the winter months. Nearly all children between the ages of 2 and 3 have been infected with RSV. In most people symptoms of RSV are mild and no different than the common cold, however, in small infants and children it can lead to bronchilolitis and pneumonia. In this population symptoms include: listlessness, poor appetite, wheezing, and fever.