Many Israelis today still maintain kosher lifestyle. The kosher diet forbids the eating of swine and other foods that have been deemed unclean. There have been studies done to confirm that a poor maternal diet can lead to Autism. It is possible that poor dietary has an effect on pregnant women to cause autism.
Fewer environmental toxins
If a mother is exposed to toxins in the environment during her pregnancy, her growing child could be at an increased risk for developing autism. Is it because Israel has far fewer environmental toxins and that could be another possible explanation for the lower autism rates.