to herpes simplex virus-2 (HSV-2) during pregnancy increases the risk of
autism spectrum disorder (ASD) in the offspring.
risk of ASD was higher if exposure to infection occurred during early
pregnancy when the fetal nervous system undergoes rapid development.
leads to activation of the maternal immune system, which is associated
with long-term developmental and behavioral problems in offspring.
actively infected with genital herpes during early pregnancy had two-fold
increased odds of giving birth to a child later diagnosed with autism spectrum disorder
findings are according to a study by scientists at the Center for Infection and
Immunity at Columbia University's Mailman School of Public Health and the
Norwegian Institute of Public Health.
‘Women who had active genital herpes during pregnancy had twice the odds of giving birth to offspring with autism spectrum disorder.’
study is the first to report an association between maternal anti-herpes
simplex virus-2 (HSV-2) antibodies and risk for ASD in offspring and to provide
immunological evidence on the role of gestational infection in autism.
believe the mother's immune response to HSV-2 could be disrupting fetal central
nervous system development, raising risk for autism," says lead author
Milada Mahic, a post-doctoral research scientist with the Center for Infection
and Immunity and the Norwegian Institute of Public Health.
risk is not due to direct infection of the fetus because such infections are
primary or reactivation of infection in mothers with inflammation in close
proximity to the womb, leads to neuro-developmental outcomes in children.
Link Between Pregnancy and Risk for
scientists wanted to examine the link between maternal infection and risk for
autism, focusing on five pathogens known collectively as ToRCH agents- Toxoplasma gondii, rubella virus, cytomegalovirus, and
herpes simplex viruses type 1 and 2.
to these agents during pregnancy can result in miscarriage and birth defects.
samples were collected from 412 mothers of children diagnosed with ASD and 463
mothers of children without ASD enrolled in the Autism Birth Cohort (ABC) Study
overseen by the Norwegian Institute of Public Health.
were collected twice, at around week 18 of pregnancy and at birth. It was
analyzed for levels of antibodies to each of the ToRCH agents.
Findings of the Study
results showed that the risk for ASD was related to high levels of antibodies
link was only evident in samples of blood taken at 18 weeks of pregnancy and
not at birth, indicating that the
risk is higher if exposure to infection occurs during early pregnancy when the
fetal nervous system undergoes rapid development.
13% of mothers in the study tested positive for anti-HSV-2 antibodies at
mid-pregnancy. Among them, only 12% reported having HSV lesions before
pregnancy or during the first trimester. This indicated that most infections
research had indicated that activation of the maternal immune system due to
infection, during early-to-mid-pregnancy is associated with long-term
developmental and behavioral problems in offspring.
the study, the effect of anti-HSV-2 antibodies on risk for ASD was only seen in
females, not males.
could be because the number of females with ASD in the ABC Study is small and
although autism is more common in males, there is a lack of evidence to
conclude that the effect is sex-specific.
research will explore the importance of screening and suppression of HSV-2
infection during pregnancy.
"The cause or causes of most cases of autism are
unknown," says senior author W. Ian Lipkin, director of the Center for
Infection and Immunity. "But evidence suggests a role for both genetic and
environmental factors. Our work suggests that inflammation and immune
activation may contribute to risk. Herpes simplex virus-2 could be one of any
number of infectious agents involved."
findings appear in mSphere
, a journal of the American
Society for Microbiology.
infection can be due to either herpes simplex virus type 1 (HSV-1) or herpes
simplex virus type 2 (HSV-2).
is also known as oral herpes, which is mainly transmitted by oral to oral
contact and it causes infection in or around the mouth.
also known as genital herpes
is a highly contagious and lifelong
infection usually spread through sex. It causes infection in the genital or
America, 1 in 5 women carries the infection and 1 in 6 people aged 14-49 years
have genital herpes.
HSV-2 virus lies dormant in nerve cells after an initial outbreak. As the body
develops resistance to the virus, the frequency of flare-ups diminishes.
417 million people aged 15-49 (11%) worldwide have a HSV-2 infection.
had the highest prevalence of HSV-2 infection at 31.5%, followed by the
Americas at 14.4%.
are more prone to infection with HSV-2 than men as sexual transmission of HSV
is more efficient from men to women than from women to men. In 2012, it was estimated
that 267 million women and 150 million men were living with the infection.
infection is often asymptomatic, or has mild symptoms that go unrecognized.
symptoms include one or more genital or anal blisters or open sores called
ulcers, fever, body aches, and swollen lymph nodes.
- Herpes simplex virus - (http://www.who.int/mediacentre/factsheets/fs400/en/)
- Genital Herpes - (https://www.cdc.gov/std/herpes/)
- Genital Herpes - CDC Fact Sheet - (https://www.cdc.gov/std/herpes/stdfact-herpes.htm)