wetter winter could be contributing to the larger numbers of mice they like to feed on, and more ticks means more tick-borne illnesses like lyme disease. the c.d.c.'s most recent data shows cases in 48 states with nearly half a million americans being treated for it every year. >> so they're looking for blood, basically. they can be as small as a poppy seed. >> reporter: parish was infected seven years ago on the beach in new jersey. at one point, she went into heart failure. >> within five month of that tick bite, i lost every part of who i was. >> reporter: scientists say it's not the sand sun bathers need to worry about, but, rather, the walk to it. these are things people in california don't think about when they're going to the beach. >> i hope that this study will bring light to the fact that it is here. >> reporter: finding ticks early support key to avoiding lyme disease, so check when you get home. and then take a hot shower. finally, put your clothes in a hot dryer, and that will kill off any stragglers you may have brought with you. norah. >> o'donnell: carter evans with