Human betaherpesvirus 5

Human betaherpesvirus 5 (HHV-5), more commonly known as Cytomegalovirus (CMV), is a type of herpesvirus that infects humans. It is a widespread and ubiquitous virus that is found worldwide. CMV is a significant pathogen in immunocompromised individuals, such as HIV patients, organ transplant recipients, and newborns. The virus is also a major cause of congenital infections, which can lead to serious developmental disabilities and fetal death.

Transmission

CMV is transmitted through bodily fluids, including saliva, urine, blood, tears, semen, and breast milk. The virus can be spread through close personal contact, transfusion of infected blood, organ transplantation, and from mother to child during pregnancy, childbirth, or breastfeeding. In healthy individuals, CMV infection is often asymptomatic or may cause a mild illness resembling mononucleosis. However, in those with weakened immune systems, CMV infection can be severe, leading to a range of complications.

Clinical Manifestations

In immunocompromised patients, CMV can cause retinitis, pneumonia, hepatitis, and gastroenteritis, among other conditions. CMV retinitis is particularly concerning in AIDS patients, where it can lead to blindness. Congenital CMV infection can result in hearing loss, developmental delay, microcephaly, and cerebral palsy in affected infants.

Diagnosis

Diagnosis of CMV infection is typically made through the detection of the virus or its components in bodily fluids. Methods include polymerase chain reaction (PCR) testing, antigen detection, and serology tests to detect CMV antibodies.

Treatment

Treatment for CMV infection involves antiviral medications such as ganciclovir, valganciclovir, foscarnet, and cidofovir. These drugs can help control the virus but do not cure the infection. In cases of congenital CMV, treatment may improve hearing and developmental outcomes in some infants.

Prevention

Preventive measures include practicing good hygiene, such as handwashing, especially among pregnant women and individuals with weakened immune systems. For high-risk groups, such as organ transplant recipients, antiviral prophylaxis may be recommended. Research is ongoing for the development of a CMV vaccine, but as of now, no vaccine is available.

Epidemiology

CMV is one of the most common viral infections worldwide, with a seroprevalence ranging from 40% to 100% in adults, depending on geographic location and socioeconomic status. Most people are infected with CMV during childhood or early adulthood.

See Also

• Herpesviridae
• Mononucleosis
• Immunocompromised host
• Congenital infection