New York, Sep 15 (IANS): Babies born to mothers who experience a bacterial infection severe enough to require hospitalisation during pregnancy may be at higher risk of developing autism, a study has found.

The study, conducted on mice, revealed that the composition of bacterial populations in the mother's digestive tract can influence whether maternal infection leads to repetitive behaviour and impaired sociability -- autistic-like behaviours in offspring.

Further, irregularities that the researchers call "patches" are most common in a part of the brain known as "S1DZ" and were responsible for the behavioural abnormalities seen in mice.

"We identified a very discrete brain region that seems to be modulating all the behaviours associated with this particular model of neurodevelopmental disorder," said Gloria Choi, Assistant Professor at Massachusetts Institute of Technology (MIT), in the paper appearing in the journal Nature.

A second study in the same jounal, revealed that not all mothers who experience severe infection end up having child with autism, and similarly not all the mice in the maternal inflammation model develop behavioural abnormalities.

"This suggests that inflammation during pregnancy is just one of the factors. It needs to work with additional factors to lead all the way to that outcome," Choi said.

Moreover, the researchers found that only the offspring of mice with one specific type of harmless bacteria, known as segmented filamentous bacteria, had behavioural abnormalities and cortical patches.

When the researchers killed those bacteria with antibiotics, the mice produced normal offspring.

If validated in human studies, the findings could offer a possible way to reduce the risk of autism, which would involve blocking the function of certain strains of bacteria found in the maternal gut, the researchers noted.