NUI Maynooth is leading an EU study into a virus that can cause foetal loss in pregnant women, writes Dick Ahlstrom, Science Editor
Dog owners are familiar with the parvovirus, which kills young dogs unless they are vaccinated against it. There is a much less well-known and unrelated human parvovirus that poses a particular threat to unborn children.
The human parvovirus B19 was discovered comparatively recently, but it is a major killer. It affects between 2,500 and 5,000 pregnancies a year across the EU, including an estimated 50 in the Republic, says Dr Sean Doyle, who is a senior lecturer in biotechnology at NUI Maynooth.
"You can't get parvovirus B19 from a dog," he says. "Same name, different virus." The organism is widespread and easily transmitted from person to person, however. "Most of us have been exposed to the virus, perhaps 70 per cent. It was discovered in 1975. Really, until the end of the 1980s the ability to diagnose the infection was limited."
It has little effect on healthy children and adults but is a particular danger to women during pregnancy and to patients just after transplant operations and those with weakened immune systems.
If a woman is infected during pregnancy, there is a 10 to 20 per cent risk of foetal loss, particularly if the infection occurs during the second trimester.
Symptoms include a rash on the face or trunk, hence the disease's common name, slapped-cheek syndrome. It is also sometimes called fifth disease, an addition to the better-known childhood diseases of measles, mumps, rubella and chickenpox.
"It is in daycare centres and schools where the virus is most readily transmitted," he says. It moves through young children who do not have immunity. They experience no long-term effect, but the background of infection can put teachers who might be pregnant or pregnant mothers at risk.
Dr Doyle leads a three-year, €1.5 million EU research initiative to develop diagnostic and treatment methods against the virus.
The consortium includes researchers from Germany, France, Finland and Sweden, as well as a second Irish partner, the biotechnology company Biotrin.
Dr Doyle headed research and development at the firm until 1997, helping to develop the first test for the parvovirus to be cleared by the US Food and Drug Administration.
After moving to Maynooth, he continued his research into B19. He wanted to look more closely at the biology of the virus and decided to make a bid for EU funding. "I essentially got everybody together and put together a work plan to bring improvements in diagnosis and to look at useful therapies."
Research funding for preliminary work came from the Health Research Board and Enterprise Ireland via the strategic research grants scheme and the Irish-American Partnership MSc programme.
The HRB funding supported research done in collaboration with Drs Bernard Mahon and Amanda Corcoran of Maynooth.
There is no vaccine for B19, so quick diagnosis through better clinical awareness is important. Current treatment involves either foetal blood transfusions, in rare cases, or treatment of the pregnant mother or immunosuppressed patient with antibodies that can target B19.
The production of a recombinant protein from the virus is what allowed the original Biotrin test to be developed, Dr Doyle says. "That essentially revolutionised the diagnosis of the disease."
He has divided the B19 research programme into several key areas. The first looks at what makes the virus so infectious and why there is so much variability in symptoms. "We want to try to find out if the virus causes this effect or if it has something to do with a person's immune response."
The team will look at cellular immunity and the way the immune system responds to the virus. "Nobody knows with the parvovirus with certainty whether past infection confers immunity, nor how much virus you need to get infected."
Ways to improve diagnosis are also on the programme, including faster antibody detection and a method of looking for viral particles very early after infection.
"Maynooth will principally be involved in the cellular side of things and the development of improved diagnostic methods," he says.
Biotrin will examine improved diagnostics and, as the only commercial company involved in the consortium, provide the group with "validated raw materials" for research purposes.
"We hope by improving awareness in the general public and with medical practitioners, they may become aware of the dangers and possible treatments."