For Dr. Mark Schleiss, finding out what causes developmental problems in children has been almost a lifelong pursuit.

“I had two siblings, a brother and a sister, who were mentally retarded,” he said.

While he had always been interested in understanding the origins of mental retardation, it was not until he treated a month-old infant who died from cytomegalovirus or CMV in the late 1980s that Schleiss found his focus – developing a cure for the virus.

“I remember being really frustrated by the fact that we had really nothing to offer,” he said.

After that, the University’s American Legion endowed professor of pediatrics began his search to solve the problem of CMV, a common but little known disease that is relatively harmless to most people, causing flu-like symptoms, but can prove devastating to newborns, potentially resulting in deafness, mental retardation or even death.

And after almost 20 years of research, Schleiss is on the cusp of achieving his goal.

Last week, University researchers, led by Schleiss, announced that they have developed an experimental vaccine to treat the virus.

The scientists injected pregnant guinea pigs with the vaccine, Schleiss said. The results: The pigs with the medication gave birth to fewer dead pups and were less likely to transmit CMV to their offspring.

Although it will probably be several years before a working vaccine can be administered to people, the next step, Schleiss said, will be to develop human clinical trials.

Within the next year, he said he hopes to set up a study giving shots to toddlers in daycare, a group prone to developing CMV.

If successful in developing a vaccine for humans, Schleiss said, pregnant women could be immunized, thus preventing unborn babies from ever developing the disease. Presently, CMV has no cure.

“It’s particularly gratifying to imagine that a vaccine, that if effective, wouldn’t just protect an infant from a disease that lasts a few days, but from a lifetime of disability,” he said.

Children with mental retardation often face numerous challenges in interacting with others and with overall development, said educational psychology professor Frank Symons.

Although he approaches the problem from a different perspective than medical doctors, Symons said it would be great if this vaccine could help prevent CMV and its effects.

At the University’s children’s hospital, doctors see rare cases of newborns with CMV, said Dr. Catherine Bendel, a neonatologist and pediatrics professor.

“Exposure to CMV is common. Severe illness with CMV is less common,” she said.

Bendel said there are roughly 70,000 babies born in Minnesota each year, and of those, about 700 are probably exposed to CMV.

Only about 10 percent of those exposed exhibit symptoms right away, and half of the infants with symptoms get really sick, she said. About 25 to 30 babies in the state are significantly affected each year.

Bendel said she still remembers the case of a pair of twins born prematurely. The boy was infected with CMV from his mother’s breast milk, though his sister was spared.

“We weren’t even sure he was going to make it for a while because he got so sick,” she said.

Despite CMV’s overall rare occurrence, Bendel said it’s sad when babies are diagnosed because it often can’t be predicted, and treatment options are limited.

“We can try and help them get through it, but there’s nothing we can do for damage that’s already occurred,” she said. “We don’t really have anything we can do to help prevent things from getting worse before they get better.”