Lymphocytic choriomeningitis virus (LCMV) is an underdiagnosed fetal teratogen. This diagnosis should be considered for infants and children with unexplained hydrocephalus, micro- or macrocephaly, intracranial calcifications, chorioretinitis, and nonimmune hydrops. The immunofluorescent antibody test is the only reasonable, commercially available, screening diagnostic tool. The differential diagnosis of congenital LCMV infection includes toxoplasmosis, rubella, cytomegalovirus, herpes simplex virus, enteroviruses, human parvovirus B19 [corrected], and syphilis. The infection has also been misdiagnosed as various neurologic, ophthalmologic, and chromosomal syndromes. Further research, to determine the prevalence of this infection in human and rodent populations, and prospective studies, to delineate the clinical spectrum of congenital infection, are needed. The public and members of the medical profession should be made aware of the hazard that wild, pet, and laboratory rodents pose to pregnant women.
