A quarterly publication of the Autism Research Institute
Winter, 2017 | Number 1, Volume 31
Women who are actively infected with genital herpes during early pregnancy have double the typical odds of having a child with autism spectrum disorder (ASD) if the child is male, according to a new study.
Milada Mahic and colleagues examined blood samples from 412 mothers of children with ASD and 463 mothers of neurotypical children. The samples were taken when the women were approximately 18 weeks pregnant and again at birth. The researchers analyzed the samples for levels of antibodies to Toxoplasma gondii, rubella, cytomegalovirus, and herpes simplex viruses type 1 and 2.
The researchers found that high levels of antibodies to herpes simplex virus 2 (HSV-2), but none of the other viruses, correlated with ASD risk. The association was detected only in the samples taken during early pregnancy.
Mahic says, “We believe the mother’s immune response to HSV-2 could be disrupting fetal central nervous system development, raising risk for autism.” She and her colleagues believe that the risk stems not from direct infection of the fetus but from inflammation in the mother.
The researchers say, “Our findings are consistent with experimental data from mouse models of gestational infection wherein vulnerability of offspring to neurodevelopmental damage depends on timing of the infection of the maternal host and associated activation of the prenatal innate immune system. Epidemiological data suggest that activation of the maternal immune system during early to mid-pregnancy is associated with long-term developmental brain and behavioral abnormality in the offspring.”
The association between maternal HSV-2 infection and ASD was seen only for male children. However, the researchers note that the number of females with ASD in their study was small.
The researchers say that 13% of the mothers in the study tested positive for antiHSV-2 antibodies at mid-pregnancy. Of this subgroup, only 12% had herpes lesions before pregnancy or during the first trimester, indicating that the majority were asymptomatic.
“Maternal immunoreactivity to herpes simplex virus 2 and risk of autism spectrum disorder in male offspring,” Milada Mahic, Siri Mjaaland, Hege Marie Bøvelstad, Nina Gunnes, Ezra Susser, Michaeline Bresnahan, Anne-Siri Øyen, Bruce Levin, Xiaoyu Che, Deborah Hirtz, Ted Reichborn-Kjennerud, Synnve Schjølberg, Christine Roth, Per Magnus, Camilla Stoltenberg, Pål Surén, Mady Hornig, and W. Ian Lipkin, mSphere, Volume 2, No. 1, January/February 2017 (free online). Address: W. Ian Lipkin, [email protected].
—and—
“Autism risk linked to herpes infection during pregnancy,” news release, Mailman School of Public Health, February 22, 2017.
