Health officials are warning people to take precautions against Lyme disease as warmer weather arrives.  Deer ticks can carry Lyme disease.  The bacterial illness can affect the heart, joints and nervous system if untreated.  The department advises undermining tick habitats by keeping grass cut short and clearing leaf litter.  People in wooded or grassy areas are also advised to wear long-sleeved shirts and long pants and to apply insect repellant.