Cytomegalovirus (CMV) is a common virus related to the herpes virus that spreads by direct contact of body fluids, such as saliva, blood, urine, semen, vaginal fluids, congenital infection, and breast milk.

Once infected, the body retains the virus for life. Most people don’t know they have CMV because it rarely causes problems in healthy people. However, it can cause concern for pregnant women and/or people with a compromised immune system. Women who develop an active CMV infection during pregnancy can pass the virus to their babies, who might then experience symptoms.

For people who have weakened immune systems, especially people who have had an organ, stem cell or bone marrow transplant, CMV infection can be fatal (Goldman L, et al., eds. Cytomegalovirus. In Goldman-Cecil Medicine. 26th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Jan. 22, 2020).

Incidence

Women infected for the first time during pregnancy are especially likely to transmit CMV to their fetuses. More children suffer serious disabilities caused by congenital CMV than by several better-known childhood maladies such as Down syndrome or fetal alcohol (Fernando; Colugnati; Staras, & Cannon. Infectious Diseases volume 7, Article number: 71. 2007).

Amongst the United States population ages 12–49 the force of infection was 1.6 infections per 100 susceptible persons per year (95% confidence interval: 1.2, 2.4). The associated basic reproductive rate of 1.7 indicates that, on average, an infected person transmits CMV to nearly two susceptible people. The average age of CMV infection was 28.6 years (1998-2020 Mayo Foundation for Medical Education and Research (MFMER).

According to Demmler-Harrison (2009) most recent studies in South Africa report lower transmission rates in early pregnancy (in comparison to later gestation) (52–58), with maternal primary infection leading to infection in 30 to 35% of fetuses and non-primary infection having a transmission rate of 1.4% in study populations predominantly from industrialised countries (1.1 to 1.7%). (Congenital cytomegalovirus: public health action towards awareness, prevention, and treatment. J. Clin. Virol. 46 (Suppl. 4)

Prevention

According to the U.S. Department of Human Health and Services: National Institute for Health, congenital CMV is a prime target for prevention not only because of its substantial disease burden but also because the biology and epidemiology of CMV suggest that there are ways to reduce viral transmission.

Because exposure to the saliva or urine of young children is a major cause of CMV infection amongst pregnant women, it is likely that good personal hygiene, especially hand washing, can reduce the risk of CMV acquisition. Experts agree that such measures are likely to be efficacious (i.e., they will work if consistently followed) and the American College of Obstetricians and Gynaecologists recommends that physicians counsel pregnant women about preventing CMV acquisition through careful attention to hygiene. However, because of concerns about effectiveness (i.e., Will women consistently follow hygienic practices as the result of interventions?), the medical and public health communities appear reluctant to embrace primary CMV prevention via improved hygienic practices, and educational interventions are rare. Current data on the effectiveness of such measures in preventing CMV infection are promising, but limited.

Perhaps no single cause of birth defects and developmental disabilities in the United States currently provides greater opportunity for improved outcomes in more children than congenital CMV. Each year in the United States, an estimated 40 000 children are born with congenital CMV infection, causing an estimated 400 deaths and leaving approximately 8 000 children with permanent disabilities such as hearing or vision loss, or mental retardation. Institute of Medicine (U.S.) Committee to Study Priorities for Vaccine Development: Vaccines for the 21st Century: A Tool for Decision making. 2000, Washington D.C., National Academy Press).

Unfortunately, the author was not able to find an updated resource regarding congenital birth defects and disabilities in South Africa.