Detection of human herpesvirus 7 infection in young children presenting with exanthema subitum

Area of Science:

• Virology
• Pediatrics
• Infectious Diseases

Background:

• Exanthematic diseases in young children are common, with diverse etiologies.
• Human herpesvirus-6 (HHV-6) is a known cause of exanthema subitum.
• The role of human herpesvirus-7 (HHV-7) in exanthematic disease requires further investigation.

Purpose of the Study:

• To assess the prevalence of HHV-7 DNA in children with exanthematic disease.
• To explore the association between HHV-7 and primary HHV-6 infections.
• To investigate the potential role of HHV-7 as an etiological agent of exanthema.

Main Methods:

• Serum samples from 141 children under four years with exanthematic disease were analyzed.
• HHV-6 infection status was determined using indirect immunofluorescence assay (IFA) for IgG and IgM antibodies.
• HHV-7 DNA was detected using nested polymerase chain reaction (PCR).

Main Results:

• HHV-7 DNA was detected in 1.7% of patients with recent primary HHV-6 infection and 5.8% with past HHV-6 infection.
• A significant proportion (25%) of samples with indeterminate HHV-6 diagnosis tested positive for HHV-7 DNA (p < 0.002).
• No association was found with measles, rubella, dengue fever, or parvovirus B19 infections.

Conclusions:

• HHV-7 DNA is present in young children with exanthematic disease in Rio de Janeiro, Brazil.
• A potential role for HHV-7 in causing exanthema is suggested, particularly in cases with indeterminate HHV-6 diagnosis.
• Careful interpretation is necessary to distinguish primary infection from virus-associated disease due to variable clinical manifestations.