Mental development scores for one-year-old babies with congenital herpes are similar to those of babies exposed to lead or cocaine in the womb.
A new study, which assessed 299 newborns over their first year of life, shows that babies with congenital infection scored several points lower than those without the infection.
“It’s not a lot. They were all within the normal range,” says Mary Caserta, professor of pediatrics and infectious disease at University of Rochester Medical Center. “But it’s similar to what you see with exposure to other toxins.
“Will that difference go away as they get older? Maybe. Will it get worse as they get older? Maybe. It’s worth looking into.”
HHV-6 is one of eight herpes viruses that infect humans. Every human is infected with HHV-6, usually in the first two years of life, and the infection often presents with fever, sometimes accompanied by roseola-like symptoms.
But for a small portion of the population, the virus is integrated into a person’s genetic chromosomes, which causes a mother to transmit it to the baby in the womb. About one percent of newborns have already been infected with the virus congenitally.
The infants in the new study, published in the journal Pediatrics, were given three intelligence tests.
For the first two—the Fagan Test of Infant Intelligence and the Visual Expectation Paradigm—there was no difference in scores between the infected infants and the uninfected infants. But for the third, a comprehensive test called the Bayley Scales of Infant Development II, the infected infants scored four points lower than their counterparts.
Caserta says she would like to test older children who have been identified with learning or cognitive disabilities to see if their rate of congenital HHV-6 infection is higher than the rest of the population.
“If children with learning disabilities have a 5 percent rate of congenital infection with HHV-6, while the rest of the population is at 1 percent, then that could be a signal that these infants do continue to have progressive developmental difficulties as they get older,” Caserta says.
“We’ve got some preliminary data that says these differences do exist, and now, we need to take the next step.”
Source: University of Rochester