The lone star tick, Amblyomma americanum, can transmit the causative agent of human monocytic ehrlichiosis. This tick also has the potential to be the vector for other agents, including those that cause Lyme Disease, Rocky Mountain Spotted Fever, and tularemia.

The American dog tick, Dermacentor variabilis, is spread across most of the United States. In the eastern half of the country, it is the most common vector of the bacterium that causes Rocky Mountain Spotted Fever. In the western half of the United States, the wood tick more commonly transmits the infectious agent that causes the disease.

The black-legged deer tick, Lxodes scapularis, also known as the deer tick. This is the adult stage, not the smaller nymphal stage that is so difficult to detect and is responsible for the majority of transmissions of the agents of Lyme disease, human granulocytic ehrlichiosis (HGE), and babesiosis.