Cytomegalovirus (CMV) infections are caused by the cytomegalovirus, a common virus that belongs to the herpesvirus family. Most people are infected with CMV during their lifetime, often without showing any symptoms. However, it can cause serious health issues in individuals with weakened immune systems, such as those with HIV/AIDS or organ transplant recipients. In healthy individuals, CMV usually remains dormant after the initial infection. In some cases, it can reactivate, leading to mild symptoms like fever and fatigue. Pregnant women are also at risk, as CMV can be transmitted to the fetus, potentially causing congenital CMV infection, which may result in developmental issues.