Detection of human herpesvirus 7 (HHV-7) DNA in breast milk by polymerase chain reaction and prevalence of HHV-7 antibody in breast-fed and bottle-fed children

Abstract

Twenty-nine breast milk mononuclear cell samples were analyzed for human herpesvirus 7 (HHV-7) DNA, human herpesvirus 6 (HHV-6) DNA, and human cytomegalovirus (HCMV) DNA by polymerase chain reaction (PCR). In addition, peripheral blood mononuclear cell samples from 13 puerperants were analyzed for HHV-7 DNA by PCR, and seropositivity of HHV-7 was also analyzed in breast-fed and bottle-fed children. HHV-7 DNA was detected in 3 of 29 breast milk samples. HCMV DNA was also detected in 3 of 29 breast milk samples, but HHV-6 DNA was not detected. HHV-7 DNA was detected in 11 of 13 samples of peripheral blood mononuclear cells. Though the seropositivity rate for HHV-7 in breast-fed children was slightly higher than that in bottle-fed children at 18 and 24 months old, the difference was not statistically significant. From these results, we speculate that breast-feeding may be one of the transmission routes of HHV-7, although this is not the main route.

Characteristics and Acquisition of Human Herpesvirus (HHV)–7 Infections in Relation to Infection with HHV‐6

“…Indeed, HHV-7 is shed from saliva in up to 90% or more of adults [3][4][5][6]17]. Furthermore, HHV-7 DNA, but not HHV-6 DNA, has been detected in breast milk samples [4,18,19]. A child's early exposure to HHV-7, therefore, would be expected to be more likely than exposure to HHV-6.…”

Congenital infections with human herpesvirus 6 (HHV6) and human herpesvirus 7 (HHV7)

“…4,[6][7][8][9][10]15,18,24 Indeed, HHV7 is shed more frequently (in $95% of adults) than HHV6 in the saliva, 6 and in contrast to HHV6, HHV7 has been detected in 10% of breast milk samples. 26 Furthermore, HHV7 may maintain a steady state of low-level reactivation or persistence in these sites. 27 Passive antibody to both viruses, therefore, as shown in our study, is uniformly present in the cord blood and at similar titers.…”

Human Herpesviruses 6 and 7 and Central Nervous System Infection in Children1

“…Infections in newborns have been previously described. Although horizontal transmission through saliva is postulated to be the most common method of transmission of HHV-6 and HHV-7 (27–29), infection in neonates as well as detection of HHV-6 DNA in aborted fetuses' cord blood and in the female genital tract suggest that transplacental or perinatal transmission is possible (30–33). …”