Cytomegalovirus (CMV) is a member of the
Herpesviridae family, which includes other viruses such as Herpes Simplex Virus and Varicella-Zoster Virus. CMV is a ubiquitous virus, meaning it is found worldwide and can infect individuals of all ages. Once infected, the virus remains latent within the host's body for life.
CMV transmission occurs through direct contact with infectious body fluids such as saliva, urine, blood, and breast milk. It can also be transmitted via organ transplantation and blood transfusions. Congenital CMV infection occurs when the virus is transmitted from an infected mother to her fetus during pregnancy.
Histological Features of CMV Infection
In histological sections, CMV infection is characterized by the presence of enlarged cells, known as
cytomegaly, with enlarged nuclei. These nuclei often contain intranuclear inclusions, giving them a distinctive "owl's eye" appearance. Additionally, CMV can cause cytoplasmic inclusions, which are dense, basophilic areas within the cytoplasm.
Common Sites of CMV Infection in Tissues
CMV can infect a wide range of tissues, but it commonly affects the
salivary glands,
liver,
lungs, and the
gastrointestinal tract. In the salivary glands, CMV infection leads to sialadenitis, characterized by inflammation and the presence of CMV-infected cells. In the liver, CMV can cause hepatitis with hepatocyte ballooning and inclusions.
Diagnostic Techniques in Histology
The diagnosis of CMV infection in histological samples can be confirmed by immunohistochemistry, which detects CMV antigens within infected cells. Another technique is in situ hybridization, which identifies CMV DNA within tissue sections. These techniques are more specific compared to routine H&E staining, which might not distinguish CMV inclusions from other viral inclusions.
Clinical Significance of CMV in Histology
CMV infection can lead to significant morbidity, especially in immunocompromised individuals such as organ transplant recipients and patients with HIV/AIDS. In these patients, CMV can cause severe diseases like pneumonitis, colitis, and retinitis. In histology, identifying CMV infection is crucial for guiding appropriate antiviral therapy and managing the patient's condition.
Prevention and Treatment
Preventing CMV infection involves practicing good hygiene, such as handwashing and avoiding contact with infected body fluids. For high-risk individuals, antiviral medications like ganciclovir and valganciclovir are used to treat and prevent CMV infections. Early detection through histological examination and appropriate treatment can significantly improve clinical outcomes.
