Roseola virus behind one-third of febrile seizures in young children

By Helen Albert

Researchers have discovered that infection with two of the roseola viruses (human herpes viruses [HHV] 6B and 7), which are responsible for a common childhood rash, appear to increase a child's risk for prolonged seizures and fever and may increase future temporal lobe epilepsy risk.

Febrile or fever-related seizures occur in 2-5% of young children, of whom many recover completely and have no further symptoms. However, less is known about outcomes in children with HHV-6B or HHV-7 infection and prolonged febrile seizures.

Leon Epstein (Northwestern University, Chicago, Illinois, USA) and team found that 32% (n=54) of 169 young children with prolonged seizures and fever were infected with HHV-6B and 7.1% (n=12) of the same group with HHV-7. Two children were infected with both HHV viruses.

The Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study included children between the age of 1 month and 5 years who were diagnosed with febrile status epilepticus (FSE) and enrolled to the study within 72 hours. All the children were tested for the presence of HHV-6B and HHV-7 in their blood.

No differences in age, characteristics of illness or fever, seizure type, or the proportion of acute electroencephalography or imaging abnormalities were seen between the children with and without infection.

The researchers say that their findings, which are published in Epilepsia, are consistent with those of previous research showing a link between HHV-6B and mesial temporal lobe epilepsy.

When asked whether children infected with the two HHV viruses were more likely to develop full-blown epilepsy at a later date, Epstein told the press: "It is possible that these patients harbor latent virus in the brain tissue that reactivates later in response to unknown triggers."

The authors explain that antivirals are not currently given to such children as testing for HHV-6B and HHV-7 is not carried out as standard, but say that clinical trials are likely to be carried out soon as more evidence is gathered.

Co-author Shlomo Shinnar (Albert Einstein College of Medicine, Bronx, New York) explained that there is some evidence for the benefits of anti-inflammatory treatment in those infected with HHV-6B.

The infection "can cause a strong cytokine response, and there is emerging data that inflammatory mechanisms may be involved in developing epilepsy after an insult such as a prolonged seizure."

He added that "it is possible that anti-inflammatory treatment could benefit these patients whether or not HHV-6B is the cause of the prolonged seizure. This is an area that needs further research."

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