Hard ticks and soft ticks have different life cycles, growing larger and changing. Of the 700 species of hard ticks and 200 species of soft ticks found throughout the world, only a few are known to bite and transmit disease to humans. Remember, that just because the tick test is positive does not mean that germs were transmitted. There are two families of ticks found in the United States: Ixodidae (hard ticks) and Argasidae (soft ticks).
Tick testing is not a substitute for physician diagnosis of disease but it can be a useful aid in deciding whether or not to treat in the absence of disease symptoms. For peace of mind and for guiding next steps, you may want to test those ticks, too. If you’ve encountered another type of tick, like the Lone Star tick, American dog tick, wood tick, Gulf Coast tick, or Pacific Coast tick, they may be infected with their own associated pathogens but they do not transmit Lyme disease bacteria. Infection prevalence for these other pathogens (Anaplasma, Babesia, Borrelia miyamotoi, Powassan virus) are typically lower and vary by region. Western blacklegged ticks also transmit the Lyme germ along with several other bacteria and parasites that can make you sick but typically <5% of those ticks are carrying germs.
For blacklegged ticks ( Ixodes scapularis) in the northeastern and upper mid-western regions, generally, 15-20% of nymphs and 50% or more of adult females are infected with Lyme disease spirochetes and risk for infection increases the longer the tick is attached and feeding.
