Can LCMV do serious damage to newborn? I see some fresh rodent droppings in my back yard where I store things. I worry if any dust from these droppings can attach to my cloth when I go there and then get to my baby when I nurse.

Lymphocytic chorio- meningitis is not a commonly reported infection in humans. Fortunately most infections are mild and often never diagnosed. However 1-5% of the US population has antibodies to this virus indicating prior infection. It seems to be more dangerous to a fetus in utero, not a newborn. Do everything you can to reduce exposure to rodents/rodent excrement by eradicating them inside and around your home.