 The fetus and infant are especially vulnerable to mercury exposures with special interest in the development of the CNS since it can easily cross across the placental barrier, accumulate within the placenta and fetus as the fetus cannot eliminate mercury and have a negative effect on the fetus even if the mother does not show symptoms.Mercury causes damage to the nervous system resulting from prenatal or early postnatal exposure and is very likely to be permanent.It is a organophosphate insecticide which acts on the nervous system of insects by inhibiting acetylcholinesterase but are moderately toxic to humans.