Deer ticks are much smaller than common dog and cattle ticks. In their larval and nymph stages, they are no bigger than a pinhead. Research indicates that ticks are most likely to transmit Lyme disease during the nymphal stage, probably because nymphs are more likely to feed on a person and are rarely noticed because of their small size. Thus, they have ample time to feed and transmit the infection, which usually requires two or more days of feeding. Ticks look for hosts from the tips of grasses and shrubs and transfer to animals or persons that brush against the vegetation.
Ticks feed by inserting their mouth parts into the skin of their host.
As they feed, their bodies slowly enlarge. The rash develops as a red circular patch which usually appears 3 days to 1 month after the bite of the infected tick. The patch then expands. The center of the patch may clear as it grows, creating a bulls-eye appearance. The rash is usually not painful.