Prevalence of serum antibodies to cytomegalovirus in pregnant women in Sapporo, Japan

Abstract

Human cytomegalovirus (CMV) is the most common cause of congenital and perinatal infections throughout the world. The prevalence of congenital CMV infection varies widely between different populations (0.2-3.0%). Less than 5% of infants with congenital CMV infection have typical cytomegalic inclusion disease, another 5% have atypical involvement, and the remainder (90%) are asymptomatic at the time of delivery.’ Even when asymptomatic at birth, 5--17% of infants with these asymptomatic congenital CMV infections will develop progressive sensorineural hearing loss or other neurodevelopmental difficulties within the first 4 years of life. We have studied the incidence of congenital CMV infection in Japan. Of 7995 Japanese neonates, 31(0.39%) were identified as having congenital CMV infections on the basis of viruria at birth. Three of 31 infants had clinically severe disease resulting in death during the neonatal period. Prospective studies of children born with asymptomatic congenital CMV infection have also revealed a wide but significant spectrum of neurologic complications. A decrease in the prevalence of serum antibodies against CMV has been seen in recent years as a consequence of improvements in the social and economic conditions in Japan in the last 20 years.* From January to December 1988, serum samples were collected from 173 Japanese pregnant women who visited a hospital in Sapporo, Japan, at 32-36 weeks of gestation. Serum samples were also obtained from 345 pregnant women who visited the same hospital at the same stage of gestation during January 1999 to June 2000. Informed consent was obtained from those participating. CMV PCS (pipetted control system) Medac IgG and IgM test kits, kindly supplied by Medac Diagnostika, Hamburg, Germany, were used to detect serum IgG and IgM antibodies against CMV. All serum samples, from both 1988 and 1999-2000, were tested at the same time. Testing and interpretation of the results were performed according to the manufacturer’s instructions. Two hundred and thirty-five of 345 (68.1%) Japanese pregnant women at 32-36 weeks of gestation had IgG and seven (2.0%) had IgM antibodies to CMV in the years 1999-2000 in Sapporo, Japan, by enzyme immunoassay. One hundred and forty-seven of 173 (85.0%) sera had IgG and one (0.6%) had IgM antibodies in 1988. One hundred and sixty-one of 354 sera (46.7%) from the years 1999-2000 showed optical density (OD) titers of IgG antibody of more than 1.000. On the other hand, only three (1.7%) of 173 sera from 1988 showed OD