Viruses as teratogens

There is nothing unique about rubella viruses or cytomegaloviruses. They are classic teratogens and, in this respect, not only follow but exemplify most of the principles of human teratology.

Viral disease of the labyrinth. I. Review of the literature and discussion of the role of cytomegalovirus in congenital deafness

Review of the literature concerning the histopathology of viral induced deafness indicates two general patterns of viral infection of the inner ear: 1) An endolymphatic labyrinthitis secondary to viremia via the stria vascularis is described in rubella, mumps, rubeola, and cytomegalovirus. 2) A perilymphatic infection secondary to meningeal, perineural, or endoneural spread is seen in varicella-zoster. Pathologic changes of degeneration and atrophy are due to inflammation and seem to be constant no matter if the infection is prenatal or postnatal. Two published reports of prenatal and perinatal cytomegalovirus infection show endolymphatic labyrinthitis similar to that casued by the other viruses. Subsequent clinical studies indicate the presence of hearing loss in mildly symptomatic and/or asymptomatic children with cytomegalovirus infections. Cytomegalovirus infection may prove to be the most significant cause of congenital and/or viral induced deafness in the future as the number of children infected with rubella, rubeola, and mumps decreases due to the use of appropriate vaccines.