Rohini,
Until you have a real risk ( Unprotected anal/vaginal, sharing needle, transfusion of infected blood) you are not at a risk
Please take your time to read about HIV transmission, since you're always near them it shall help you to rule out the myths about HIV.
http://www.cdc.gov/hiv/pubs/facts/transmission.htm
Just avoid exposures to blood, everything else carries negligible risk.
NO, you are not at risk and there is no way to put yourself at risk. HIV is a sexually transmitted disease and by sharing needles.