Photo Credit: Petty Officer 3rd Class MacKenzie Adams
In a recent study of a large Norwegian population, researchers have discovered a correlation between the infection of pregnant women with the herpes simplex virus type 2 (HSV-2) and the development of autism spectrum disorder (ASD) in the first few years of life.
The study does not show that the HSV-2 virus causes ASD, but it does suggest that the presence of HSV-2 in a pregnant mother may promote the onset of ASD in the child. The causes of ASD are not well understood, and the findings do not suggest that all mothers infected with HSV-2 will have children with autism.
In the study, 442 mothers of children with ASD were paired with 464 mothers of children without ASD. Their blood samples from mid-pregnancy to birth were made available and tested for antibodies for five different infections.
The presence of antibodies for HSV-1, HSV-2, Cytomegalovirus, Toxoplasma gondii, and/or Rubella would suggest that the mother was infected during, or a few weeks prior, to that point in pregnancy.
Mothers who exhibited high levels of antibodies for HSV-2 during mid-pregnancy were found to be twice as likely to give birth to a male that would be diagnosed with ASD. However, not enough female babies were born to draw conclusive evidence about girls. The four other infections tested did not produce similar discrepancies in the rate of ASD.
Some scientists remain skeptical that the inflammatory molecules that appear because of an HSV-2 infection are enough to cause ASD. Peter Hotez, a vaccine scientist and pediatrician at the Baylor College of Medicine, states, “The changes in the architecture of the neocortex in the brains of kids with autism are so profound that it’s hard to imagine how an inflammatory response, even in utero, is going to cause that.”
Many still believe there are significant genetic and environmental factors that must also be considered when assessing the risk of a child to be later diagnosed with autism. Future studies will focus on why the four other infections tested did not produce similar results and if similar rates of ASD will be seen in female children.
Sources: Wadman M. Herpes virus may be a trigger for autism. Science.