Will exposure to anthrax harm my child?

Yes. Anthrax is a serious illness. See this site for more info. http://www.mayoclinic.com/health/anthrax/ds00422.
See a doctor. Anthrax commonly affects hoofed animals such as cows, but humans who come into contact with infected animals can get sick from anthrax, although I have not heard of an outbreak in the US in awhile. Cutaneous anthrax is not spread from person to person. If you or your child has been exposed to anthrax, see a doctor that specializes in infectious diseases.