Cytomegalovirus, often called as CMV, is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Monkeys and human beings serve as natural hosts which play an important role in CMV’s life cycle. As we know, human CMV (HCMV, human herpesvirus 5, HHV-5) is the most studied of all cytomegaloviruses because this species infect humans and associate with different diseases including pneumonia and glandular fever.
CMV belongs to the Betaherpesvirinae subfamily of Herpesviridae. It is related to other herpesviruses within the subfamilies of Alphaherpesvirinae that includes herpes simplex viruses (HSV)-1 and -2 and varicella-zoster virus (VZV), and the Gammaherpesvirinae subfamily that includes Epstein–Barr virus. Figure 1 shows the schematic of Cytomegalovirus:
Fig. 1 Model of Cytomegalovirus
Cytomegalovirus is a double-strand DNA virus, with icosahedral, Spherical to pleomorphic, and Round geometries, and T=16 symmetry. Figure 2 indicates that CMV enveloped with an outer membrane, different proteins including glycoprotein 116, 58 and 86 chimerized in it. Those glycoprotein conduct the infection or release of genetic substance of virus.
Fig. 2 Inter Structure of Cytomegalovirus
Cytomegalovirus’ or CMV’s replication is nuclear and lysogenic. Virus gets through the cell membrane by using its viral glycoproteins to capture the host receptors which located in the surface of host cells. Those receptors mediate a process of endocytosis, and after CMV gets into cells, it will start a replication of double-strand DNA in a bidirectional copy model: DNA templated transcription, accompanying some alternative splicing mechanism is the method of transcription. Translation takes place by leaky scanning. The virus exits the host cell by nuclear egress, and budding.
Although CMV spreads directly through contacting of body fluids, such as blood, saliva, urine, vaginal fluids, and breast milk, most healthy people don’t undergo any symptoms when infected with CMV and it doesn’t experience a serious health concern. Most adults have antibodies against CMV after them recovering from past infection.