Cytomegalovirus (CMV) infections are caused by a common herpesvirus known as Human Cytomegalovirus (HCMV). This virus infects people of all ages, and while it often produces mild or asymptomatic symptoms in healthy individuals, it can pose serious risks to those with weakened immune systems. CMV is primarily transmitted through bodily fluids such as saliva, urine, blood, and breast milk. In healthy individuals, the immune system can usually control the infection, leading to a latent phase where the virus remains dormant. However, in immunocompromised individuals, such as those with HIV/AIDS or organ transplant recipients, CMV can cause severe complications, including pneumonia, retinitis, and gastrointestinal issues. Additionally, CMV infections during pregnancy may lead to congenital disabilities in newborns. Diagnostic methods include polymerase chain reaction (PCR) tests and serological assays, while antiviral medications like ganciclovir and valganciclovir are commonly used for treatment.