Human herpesvirus-7 as a cause of exanthematous ilnesses in Bel�m, Par�, Brazil

ABSTRACT

We screened sera from 370 patients suffering from exanthematous illnesses in Bel�m, North Brazil, for the presence of human herpesvirus-7 (HHV-7) IgM and IgG antibodies. Samples were obtained from January 1996 to December 2002 and were processed by a HHV-7-specific indirect immunofluorescence assay (IFA). HHV-7-specific IgM and/or IgG antibodies were found in 190 (51.4 per cent) of these patients, with similar prevalence rates (IgM+ and IgG+ subgroups taken together) for female and male subjects: 52.5 per cent and 50.3 percent, respectively. Serological status as defined by IgG was identified in 135 (36.5 per cent) patients. In 55 (14.9 per cent) of the patients HHV-7 IgM antibodies were detected. HHV-7 IgM- and- IgG antibody rates were similar (p > 0.05) when male and female subjects are compared 14.4 per cent versus 15.3 per cent and 38.1per cent versus 35.0 per cent, respectively. Statistically significant difference (p = 0.003) was noted when HHV-7-IgM-positive female and male patients aged 5-8 months are compared. Prevalence rates ranging from 4.6 per cent (female, 5-8 months of age) to 93.3 per cent (female, > 10 years of age) and 12.2 per cent (male, 5-8 months) to 80.0 per cent (male, 8-10 years of age) were noted in the IgG- positive subgroups. A subgroup (n = 131) of patients with IgM or IgG HHV-7 antibodies were examined for the presence of DNA using a polymerase chain reaction/nested PCR. Recent/active HHV-7 infection occurred at a rate of 11.0 per cent (6/55) among patients whose samples presented IgM+ specific antibodies. In a subgroup (n = 76) of patients with high HHV-7-IgG antibody levels (titre > 1160) DNA could not be detected in sera examined by PCR/nested PCR. Of the six recent/active infections, four subjects with less than 1 year and two with 3 and 6 years of age, presented typical exanthem subitum (E.S), as defined by higher fever (> 38.0 �C) with duration of 24 to 72 hours, followed by a maculopapular skin rash. Our results underscore the need for searching HHV-7 infection in patients with exanthematous diseases, particularly those presenting with typical E.S. HHV-7 appears therefore to emerge as a newly recognized pathogen of exanthem in our region...(AU)